SUBARU Body Repair Technical Skills Handbook

SUBARU Body Repair Technical Skills Handbook
SUBARU
Body Repair Technical Skills Handbook
Introduction
This manual sets out know-how required to carry out auto body repair for those wanting to acquire
auto body repair skills through to those already engaged in repair work in the course of their
jobs.
It goes without saying that knowledge, a sense for the work and practical know-how acquired
through practical experience are important when acquiring expertise in body repair. However, at
a time when advances to the quality of materials, construction and assembly precision used in
vehicles are improving at an almost daily rate, gaining a firm understanding of basic knowledge
is essential for carrying out effective and reliable repairs of a quality that will meet with customer
satisfaction.
This handbook will first describe basic knowledge of health and safety, vehicle body construction,
and then cover the basic procedure step by step from external panel repairs and underframe
repairs, to the replacement of welded panels, providing general examples.
Table of Contents
Subaru · Body Repair
Technical Skills Handbook
Health and safety measures
1
Body construction
2
Body materials
3
Repair procedures
4
External panel repair
5
Sheet metal treatment
6
Damage analysis
7
Removal and fitting of parts
8
Repair of the underframe
9
Handling of welding equipment
10
Replacement of welded panels
11
Repairing aluminum alloy and plastic panels
12
Quality inspection
13
Appendices
FUJI HEAVY INDUSTRIES LTD.
Health and safety measures 1 - 1
Chapter 1 Health and safety measures
Contents
1. Safety measures at work ............................................................................................................................... 2
2. Use of protective gear ................................................................................................................................... 2
(1) Clothing ..................................................................................................................................................... 2
(2) Head gear .................................................................................................................................................. 2
(3) Safety boots .............................................................................................................................................. 2
(4) Safety glasses ........................................................................................................................................... 2
(5) Dust mask .................................................................................................................................................. 3
(6) Face shield ................................................................................................................................................. 3
(7) Welding helmet (auto-darkening helmet)................................................................................................ 3
(8) Ear plugs (ear muffs)................................................................................................................................. 4
(9) Gloves: Work gloves (heavy cotton), welding gloves, gloves for handling solvents,
high voltage insulating gloves................................................................................................................. 4
3. Precautions ..................................................................................................................................................... 5
(1) Protecting bodywork and interior and exterior fittings . ........................................................................ 5
(2) Preventing fires and explosions .............................................................................................................. 6
(3) Health and safety related to body repair ................................................................................................ 7
(4) Health and safety related to painting work . ........................................................................................... 8
4. Maintaining a tidy workshop . ...................................................................................................................... 9
Health and safety measures 1 - 2
1. Safety measures at work
Various kinds of machinery, equipment, tools and materials are used in body repair work. Body repair involves
highly dangerous work, including the generation of intense heat and strong light when welding and fusing, dust
and fires during sanding, and the handling of panels and parts with sharp edges. To protect oneself and prevent
accidents, it is important to learn about safety measures and to wear protective gear suitable for each task.
À Follow the prescribed methods for using equipment, machine tools and materials.
Á Use the correct equipment, machine tools and materials for each task, and do not use equipment for tasks
for which they are not designed.
 Regular maintenance of equipment and machine tools and maintenance after use, depending on what
they are used for, must be carried out (checks, cleaning, lubrication as necessary, etc)
à Maintain a suitable body posture and use necessary supports.
2. Use of protective gear
The following protective gear is used when carrying out panel work.
(1) Clothing
When engaged in welding work where sparks are generated, wear a welding apron and arm and leg protectors.
Do not wear short-sleeve summer clothing when welding.
(2) Head gear
Head gear must be worn at all times for protection from sparks, iron powder, dust, etc. If the visor gets in the way
due to the site you are working on or because of other protective gear you are wearing, don't remove your head
gear but wear it backwards.
It is recommended that helmets be worn when doing body work.
(3) Safety boots
Safety boots prevent slipping, the thick soles protect the soles of your feet from sharp objects, and the steel caps
protect toes from heavy objects. The surface is resistant to sparks and other hazards.
(4) Safety glasses
There are safety glasses that prevent dust from getting into the eyes and auto-darkening helmets worn when
welding. Safety glasses protect the eyes not only from paint and body filler dust, but also from metal powder
when cutting panels and from sputters when stud or spot welding. The rim adheres to the skin, thus preventing
dust and other matter from getting inside.
When MIG welding while making body repairs, use a welding helmet and not an auto-darkening helmet.
Health and safety measures 1 - 3
(5) Dust masks
Wear a dust mark so you don't breathe in paint, dust particles, metal power or welding fumes.
Dust masks are mainly worn when using body filler following panel work. There are masks that contain activated
carbon.
Replace with a new one when use reaches the time limit for use.
(6) Face shields
Faces shields protect the face from metal power and from sputters when welding. Although safety glasses seal
tightly, dust can get into the eyes through gaps. This risk is lowered by using a face shield and safety glasses
together.
Some face shields also serve as welding masks.
(7) Welding helmets (auto-darkening helmets)
Welding helmets protect the eyes and face from strong light and ultraviolet light when MIG welding. There is a
hand-held type and a type worn on the head.
There are also auto-darkening welding helmets that use a liquid crystal filter.
Health and safety measures 1 - 4
(8) Ear plugs (ear muffs)
Ears should be protected from loud noise, such as the noise of hammering, the setting and re-setting of equipment, and cutting noise when using air tools to cut panels. If ear protection is not used when engaged in repair
work for long periods, noise and wavelengths not audible to the human ear can harm hearing, and in some
causes cause deafness.
There are ear plugs that are easily inserted into the ears, and ear muffs that cover the ears.
(9) Gloves: Work gloves (heavy cotton), welding gloves, gloves for handling
solvents, high voltage insulating gloves
Wear gloves appropriate for the particular task. Use heavy cotton gloves when performing general tasks. There
are slip-prevention cotton gloves that have a rubber coating on the palm side, and high-strength gloves that use
Kevlar protection.
Avoid using cotton gloves when drilling because the tips can get caught.
Gloves made from animal skin are suitable when welding or repairing the underframe.
There are also solvent resistant gloves for use when handling degreasing agents and paint, and special rubber
gloves for use when working on high voltage sites.
n Use of protective equipment
Head gear
Safety glasses
Cap
Ear plugs
Dust mask
Various types
of gloves
Safety boots
Face shields
Welding
helmets
Health and safety measures 1 - 5
3. Precautions
(1) Protect bodywork and interior and exterior fittings
Bodywork can be smudged and scratched during body repair work. Prevent this by protecting the area around
the work site. Use a sheet or a special protective cover.
1) Prevent dust when sanding using a sander, etc.
Prevent areas beside the repair site from being dirtied by dust generated when sanding paint or body filler. Be
particularly careful with regard to the passenger compartment and engine bay. Protect the surrounding area using sheets, covers and masking materials.
2) Prevent interior fittings from getting dirty
Prevent dust from adhering to the seats, steering wheel and other parts of the passenger compartment by protecting them with plastic sheets and covers.
3) Prevent sparks during welding
Protect the vehicle body from sputters and sparks during welding by covering it with fire-proof sheets (cloth and
paper).
4) Protect the surrounding area when making body repairs and treating the substrate.
When making body repairs or treating the substrate, protect the surrounding area by attaching masking tape or
plastic tape so that the sander does not damage the pinstripe or other nearby parts.
Health and safety measures 1 - 6
(2) Prevent fires and explosions
Many pieces of equipment used for body repair can easily catch fire or explode. Be extremely careful when handling such items.
1) Gasoline
When siphoning gasoline, be sure to comply with fire regulations. Work in an area with good air flow and warn
nearby workers. Do not use a plastic pump or tank that generates static electricity when siphoning or for storage.
Store the siphoned gasoline in a specified safe storage place.
If gasoline leaks onto the floor of the workshop, do not leave it but wipe it up straightaway.
2) Paints
With the exception of water-based paints, most paints are flammable. Store them in a specified place and do not
leave them lying around elsewhere. As an environmental protection measure, always secure lids and caps to
prevent the evaporation of volatile organic compounds.
Also be careful when disposing of leftover body filler, cloths containing organic solvent-based degreasing agents
and used paint cans, as there is the risk of spontaneous combustion.
* Volatile Organic Compounds
3) Gas cylinder
Be careful when handling acetylene gas, oxygen gas, carbon dioxide gas, argon gas, etc used when welding and
also watch out for hose deterioration and the aging of equipment.
4) Naked flames and other fire sources strictly prohibited
Welding sparks can cause flammable gases to explode when gases reach a specified concentration within an
enclosed space. Therefore, do not bring any fire sources into the workshop, except those required for work.
Smoking is prohibited while working. Use a specified smoking area.
n Many pieces of equipment used for work are highly dangerous
Paint
Carbon
dioxide gas
Gasoline
Acetylene
gas
Health and safety measures 1 - 7
(3) Health and safety related to body repair
1) Body repair work
Body repair and welding work are highly dangerous tasks.
Body repair work can cause serious damage or injury due to the heavy items and large force handled. Pay attention to the following to prevent serious damage or injury.
À Securely fasten bolts, nuts etc on repair equipment and check they are not loose.
Á When pulling, be prepared in case the clamp should come off by staying out of the area where the chain
or clamp is likely to land. Attach a safety wire so that the clamp is restrained if it comes off.
 Follow instructions for the use of jacks and hoists carefully, and when going under a vehicle always
support the vehicle securely with rigid racks, etc.
2) Using jacks
When jacking up a vehicle or supporting a vehicle with rigid racks, follow the instructions and weight limits in the
service manual.
Check carefully to see whether the vehicle is stable or not.
When jacking only the front or rear, make sure that the wheels are locked.
Do not leave a vehicle in a jacked up position.
n Vehicle is jacked using rigid racks
3) Welding work
Providing that there is nothing wrong with a welder it will not cause electric shocks or catch fire. However, regular
checks are essential.
Pay attention to the following when welding.
À Gas produced when welding is toxic so wear a protective mask.
Á Looking directly at a flame when welding can, at worst, lead to the risk of blindness. Always wear a
welding helmet or safety glasses.
 When using an oxygen or acetylene gas welder, check there are no flammable items in the surrounding
area, as these welders produce naked flames.
Health and safety measures 1 - 8
4) Electrical work
When doing wiring or other electrical work, make sure the ignition switch is turned off and remove the connector
to the negative terminal on the battery.
If there is a risk of the generation of static electricity, do not touch the control unit, connector or other similar
parts. Either use an anti-static electric cord or start work after removing the static electricity by touching earthed
metal.
n Remove the connector from the negative terminal on the battery before starting work
(4) Health and safety related to painting work
1) Body filler
Coming into contact with sanding dust produced when applying body filler after body repair harms respiratory
function, causing pneumoconiosis etc. Use a dust mask when applying body filler. Also use a sander that collects
dust. However, since the use of a dust-collection sander alone will not completely take care of the body filler dust,
work in a place with a dust collection system that suctions dust from the floor and wall surfaces.
When cleaning after sanding, wear a dust mask and lower the pressure of the duster gun used for blowing so that
the dust does not scatter over a wide area.
n Be careful with dust when using body filler
Dust mask
Dustcollection
sander
Dust-collection hose
Grating of dust-collection device
Health and safety measures 1 - 9
4. Maintaining a tidy workshop
A tidy workshop is the first rule of safety. All equipment, tools and materials should be stored in a pre-determined
place, and returned to their original places after use. Leaving machine tools and materials on the workshop floor
is very dangerous, as you can easily trip over them.
Arrange the items you will need in a tool cart beforehand, place the cart near the vehicle you are working on and
take the items from the cart and put them back while working. This prevents machine tools from cluttering up the
floor. It also makes for more efficient work.
n Being tidy prevents dangerous situations
Maintaining a tidy
workshop
It's easy to trip over tools left lying on the floor
Health and safety measures 1 - 10
Body construction 2 - 1
Chapter 2 Body construction
Contents
1. Passenger Vehicle Frames ............................................................................................................................. 2
(1) Ladder-type frame ..................................................................................................................................... 2
(2) Platform frame .......................................................................................................................................... 2
(3) Space frame .............................................................................................................................................. 2
(4) Backbone frame ........................................................................................................................................ 2
2. Characteristics of the unitized body ............................................................................................................ 3
3. Rigid and truss structures ............................................................................................................................. 4
4. Characteristics of the crash safety body ...................................................................................................... 5
5. Structure of body sections ............................................................................................................................ 6
(1) Front body ................................................................................................................................................ 6
(2) Center body ............................................................................................................................................... 8
(3) Rear body ................................................................................................................................................ 10
Body construction 2 - 2
1. Passenger Vehicle Frames
A monocoque body structure is adopted in passenger vehicles, where there is a single frame that supports the
body, engine and suspension and absorbs force while the vehicle is in motion.
There are other frames with a variety of structures besides the monocoque body. They are broadly divided into
the following.
(1) Ladder-type frame
Two parallel rails are joined by cross members, and as the
name suggests it is a simple structure in the shape of a ladder. This frame is used for trucks and 4-wheel drive vehicles.
This is also called a ladder frame.
They are mainly used in passenger vehicles because they
allow a large passenger compartment and have a low perimeter frame.
(2) Platform frame
This frame's structure has robust floor panels that serve as
the frame.
(3) Space frame
This frame is made up of pieces of tubing. With a shape like
that of a motorbike frame, the complex structure is not suited to mass produced vehicles.
(4) Backbone frame
With a spine in the center, like the space frame this backbone
frame is suited to small production sports cars.
Body construction 2 - 3
2. Characteristics of the unitized body
An egg is an example of a shell-type structure, which can withstand a considerable amount of force when applying force using a finger on the top or bottom. This is because the force is not concentrated but is absorbed by the
entire exterior of the shell. Called stressed skin construction, it is used in the design of aircraft.
Like an egg shell, the outer skin made of a uniform material spreads force applied to one part across the entire
body, thus maintaining strength.
Because a vehicle body has opening parts like doors and the engine bay, pillars and members are used to ensure
strength. Since the amount of force received differs from site to site, strictly speaking this can't be called a unitized structure.
In Japan this is referred to as a "monocoque" body, whereas overseas it is called a unitized body or frameless
body.
In a unitized body the underframe is made of closed section members and the heavy engine, suspension, steering, etc are attached directly to the underframe. One notable feature of this type of construction is that it allows
the use of panels that are thinner than a frame. This is a good structure from the point of view of its light weight,
impact safety, and mass producibility.
n Egg shell has a stressed skin structure. The force is absorbed by the entire
exterior of the shell.
n A vehicle is not really like an egg, as it has many opening parts.
Body construction 2 - 4
3. Rigid and truss structures
The frames of ordinary buildings have a rigid structure and a truss structure. Beams and perpendicular members
form a quadrangle, which form a house or building when supported by pillars. In a rigid structure, the contact
points have rigid joints.
A rigid joint is a joint that has been welded so that it can't move.
A truss structure has a triangular shape like that seen in steel bridges. In a truss structure, the contact points are
sliding joints. Sliding joints are joints that move and slide, and reinforced braces are inserted on the diagonal to
ensure safety. This creates triangular layers like those in steel bridges.
As a two-dimensional flat surface, when strong force is applied from above, the four corners not only deform
outward on the rigid joints of the rigid structure, but the right and left members also deform. However, in a truss
structure that is connected with sliding joints, only the upper members deform and absorb the force.
The body of a vehicle is not a closed external wall like an aircraft with a shell structure, as the underframe is made
up of a combination of panels with many opening parts. The passenger compartment in the middle has a rigid
structure, as well as a shell structure in which the entire frame can distribute the absorption of external force.
The front and the rear each have a rigid structure, and building on top of this forms the body's (chassis) unitized
structure.
n Rigid structure
n Truss construction
Structure assembled by fixing (rigid joints) members
Structure assembled (flexible joints) so that members can rotate
Example: Buildings Example: Steel bridges
n A vehicle body is a series of rigid structures
Body construction 2 - 5
4. Features of the crash safety body
A vehicle body does not only have to be strong, but when it receives an impact in an accident, for example, its
structure must be such that as much as the impact force as possible is not transmitted to the passengers. Bodies
designed taking this in account are called impact absorption structures and crash safety bodies.
Special design features are included in an impact safety body.
One is disintegration of the part that receives the impact as a means of absorbing the force. Of course, this does
mean that the structure is such that the entire body simply disintegrates. Sections that concentrate stress are put
in the underframe structure at the front and rear of the body. The structure has sharp curves, a crinkle pattern,
and open punch holes. These "impact zones" disintegrate as they were designed to do when the body receives
an impact.
n Structure absorbs energy from the front
Torque box
Floor cross
member
Side sill
n Structure absorbs energy from the side
Floor rear cross
member
Side door beam
Front side member
Floor cross
member
Floor side member
Floor rear cross member
Body construction 2 - 6
5. Structure of body sections
(1) Front body
Heavy parts integral to vehicle motion, such as the engine and transmission, are found in the front body. They
must support the force received from the front wheels via the suspension. In front-wheel drive vehicles, the front
body also takes the weight and drive force of the differential gear and drive shaft. Consequently, members and
reinforcements have a dual hanging rack structure, and the various joints also have a robust structure made by
adding reinforcement. The underframe members of front-wheel drive vehicles are thicker than those of rearwheel drive vehicles, and sometimes the toeboard joints have complex shapes.
The role of the front side frame is to absorb and distribute energy upon impact.
The front end has a significant amount of open space for the mounting of the radiator and headlamps. Cross
members are fitted underneath and rather detailed upper members above the front end.
At the sides there are lower side members underneath that support the engine and suspension, and from the
wheel apron it is covered by the suspension brackets, which are fitted above the shock absorbers. The upper
member is incorporated and reinforced above the apron parallel to the upper member.
There is a toeboard connected to the floor on the passenger compartment side of the front body. Members and
reinforcements are welded and take up a large area, and are combined with reinforcing materials. In front-wheel
drive vehicles, attachment rigidity is enhanced by placing side members from the bottom of the toeboard to the
floor. In some cases a sandwich structure using asphalt sheets is used to effectively absorb engine noise and
vibration.
The bolted on hood and front fender have minimal effect on strength. However, the shape and structure of the
hood have changed recently to protect pedestrians when collisions occur.
Body construction 2 - 7
n Front body structure and parts
36
11
10
6
9
8
1
6
10
7
3
11
13
3
2
33
33
15
14
35
13
12
4
31
17
17
37
27
28
25
5
22
21
32
7
26
16
34
29
35
18
18
30
25
19
28
26
24
22
23
23
18
18
24
17
17
16
19
31
20
High tension steel
1.
Upper radiator member
14. Left front wheel apron
27.
2.
Hood lock stay
15. Left fender bracket
28. Toeboard side cross member
3.
Radiator side stays
16. Front side front member
29. Pitching stopper bracket
4.
Lower radiator panel member
17.
30. Toeboard center cross member
5.
Lower radiator member
18. Spacer
31. Side member
6.
Front suspension bracket
19. Front member gusset
32. Front panel and duct
7.
Closing plate
20. Front of front member blade
33. Front panel
8.
Right fender bracket
21. Plate A
34. Toeboard
9.
Right front wheel apron
22. Plate B
35. Gusset
10. Upper front wheel apron
23. Hook pipe
36. Hood
11.
24. Front member gusset C
37.
Upper side member
Front bumper bracket
12. Battery bracket
25. Rear front side member
13. Front tie-down
26. Toeboard reinforcement
Front floor cross member
Front fender
Body construction 2 - 8
(2) Center body
The center body is the passenger compartment used for passengers and goods. The interior space is like an
empty box, as there are no structures that have to be installed transversely from right to left or top to bottom.
With doors and windows, a large area of the center body opens.
As a result, there are pillars that extend vertically from the floor panel to support the roof panel. The number of
pillars is determined by the number of doors. There is a raised floor tunnel running from front to back in the center and a box-section side sill on both sides that supports the weight of the passengers and cargo.
The sides are the same thickness as the doors. It is not possible to construct an impact absorbing structure like
that used at the front or rear. As a result, each pillar has a closed cross section structure with and outer and inner
panel, and a three-layer structure is created by disposing reinforcements between the panels. Reinforced panels
are used to provide a robust structure for hard top bodies and convertibles that do not have a center pillar.
Mechanisms to raise and lower the windows and to lock the door are contained inside the doors, and side door
beams are adopted to enhance impact safety when a side impact occurs. This reduces the amount of deformation
when the door receives impact.
Body construction 2 - 9
n Center body structure and parts
3
5
1
4
2
13
6
18
24
12
12
20
21
14
21
19
25
11
15
23
10
7
26
17
16
8
22
9
34
36
36
32
33
33
31
37
37
40
38
34
39
29
35
32
27
31
28
High tension steel
29
30
1.
Roof panel
17.
Front pillar outer
2.
Front roof rail
18. Center pillar outer
34. Side sill inner
3.
Rear roof rail
19. Rear quarter outer
35. Front pillar lower inner
4.
Roof center brace
20. D-pillar extension
36. Front seat rear cross member
5.
T-stud plate
21. Rear quarter end
37.
6.
Side rail inner
22. Side sill outer
38. Hand brake reinforcement
7.
Front pillar upper inner
23. Front pillar door reinforcement
39. Front door
8.
Front pillar center inner
24. Side rail reinforcement
40. Rear door
9.
Side sill reinforcement inner
25. Center pillar reinforcement
10. Center pillar inner
26. Side sill reinforcement outer
11.
27.
Rear quarter inner
Instrument panel bracket
12. D-pillar reinforcement assembly
28. Floor center cross member
13. D-pillar inner
29. Front floor front member
14. D-pillar reinforcement
30. Floor rear cross member
15. Rear quarter center reinforcement
31. Toeboard upper reinforcement
16. Rear arch inner
32. Front floor rear frame
33. Front floor pan
Front seat front cross member
Body construction 2 - 10
(3) Rear body
The structure of the rear body differs according to whether or not there is a trunk lid. Although the structure is
similar to the structure of the front body, there is a floor panel covering the bottom. It incorporates the same impact absorption structure as the front.
Because it is difficult to ensure strength in cabover wagons or vans, a member rather similar to a ladder frame is
welded to the floor.
Somewhat different rear body structures are used for models with a separate trunk, hatchbacks and vans. Basically, there are quarter panels that incorporate the rear pillars at the side, a rear skirt at the back-end, a rear floor
pan that serves as the floor to the trunk, and rear side frames welded to the other side of the floor pan. In models
that have a trunk a panel separates the passenger compartment and the trunk.
Quarter panels are constructed with an inner and outer panel, and the inner side is joined to the rear arch which
forms the wheel housing.
The rear floor pan is joined directly to the passenger compartment floor. The rear side frame on the other side is
thinner and smaller than the front side frame. This is because it does not require the same strength as the front.
Body construction 2 - 11
n Rear body structure and parts
4
8
5
6
2
7
3
17
17
55
4
9
13
12
12
10
12
12
11
3
13
21
14
1
15
9
10
16
11
High tension steel
1.
Rear floor front pan
7.
Spare tire bracket
13. Rear floor side
2.
Rear floor rear pan
8.
Rear skirt
14. Rear floor cross member C
3.
Front side upper member
9.
Front floor side member
15. Rear floor cross member B
4.
Rear side upper member
10. Rear suspension bracket
16. Rear floor cross member A
5.
Rear of rear side upper member
11.
17.
6.
Spare tire reinforcement
12. Rear floor side member
Rear side sill inner
* Refer to the diagram of the center body for a drawing of the side panels.
Tail gate
Body construction 2 - 12
Body materials 3 - 1
Chapter 3 Body materials
Contents
1. Types of materials .......................................................................................................................................... 2
2. Properties of metal ....................................................................................................................................... 3
(1) Common properties . ................................................................................................................................ 3
(2) Mechanical properties .............................................................................................................................. 4
3. From iron to steel . ......................................................................................................................................... 4
(1) Sheet metal manufacturing process ....................................................................................................... 5
4. Type of sheet metal ........................................................................................................................................ 6
(1) Hot-rolled sheet metal and cold-rolled sheet metal . ............................................................................. 6
(2) Corrosion-resistant sheets ....................................................................................................................... 7
(3) High tensile strength sheet metal . .......................................................................................................... 8
(4) High-damping sheet metal . ..................................................................................................................... 8
5. Properties of sheet steel . .............................................................................................................................. 9
(1) Plasticity and elasticity ............................................................................................................................. 9
(2) Work hardening ......................................................................................................................................... 9
(3) Work hardening of panels....................................................................................................................... 10
(4) Tensile strength ....................................................................................................................................... 11
6. Aluminum alloys........................................................................................................................................... 12
(1) Types and characteristics ........................................................................................................................ 12
7. Plastic ............................................................................................................................................................ 13
(1) Types and characteristics ........................................................................................................................ 13
(2) Plastic body parts and materials . .......................................................................................................... 14
8. Glass ............................................................................................................................................................. 16
(1) Safety glass ............................................................................................................................................. 16
(2) Special glass . .......................................................................................................................................... 17
(3) How to distinguish types of glass ......................................................................................................... 17
Body materials 3 - 2
1. Types of materials
Sheet metal is the main material used in body panels. A variety of elements are added to iron, and flat stretched
sheets used as exterior panels are 0.6 – 0.8 mm thick and those used for pillars and frames (members) are 0.8 –
1.4 mm thick.
Corrosive resistant sheets are used for sites where rust prevention is important, and high tensile strength sheets
are used for sites requiring high strength. Corrosive-resistant sheetmetal is normally zinc plated on both sides.
Repairing corrosive-resistant sheets sometimes requires special treatment before applying putty or primer
surfacer before painting.
Because high tensile strength sheets can have the same strength as standard sheetmetal even though they are
thinner, they were initially adopted for large flat panels, such as the hood and doors, as a means of reducing
weight. Today, however, they have a wide range of uses, including frames (members), pillars and reinforcements.
Some exhibit slightly different properties compared with standard sheetmetal with respect to the way they deform
when damaged and when they are repaired.
Aluminum alloys and plastic are two other materials used for vehicle bodies. Aluminum alloys with the same
strength as sheetmetal is lighter, and so are used to reduce the weight of vehicles. Because the properties of
aluminum alloys are different from steel, they require different handling for body repair, welding and painting.
Although plastic is mainly used for bumpers, the front grille, moldings, and interior components, plastic is also
used for body panels. Repair methods vary depending on the type of plastic, and can require special tools and
materials.
n Body materials
Steel
Aluminum
Standard sheetmetal
Thin standard sheetmetal ranging in thickness from 0.6 mm to
0.8 mm are used depending on the section.
high tension steel
high tension steel with the same thickness as standard sheets
have higher strength.
Corrosive-resistant
sheetmetal
Sheets are made rust-resistant by zinc plating either one side or
both sides.
Aluminum alloys used
for body panels
Aluminum alloy panels that weigh approximately half as much
as sheetmetal have the same strength.
ABS
Acrylonitrile butadiene styrene
BMC
Bulk molding compound
Plastic
PA
Polyimide = nylon
PC
Polycarbonate
PE
Polyethylene
PP
Polypropylene
PUR
Polyurethane
PVC
Polyvinyl chloride
SMC
Sheet molding compound
FRP
Fiber-reinforced plastic = fiberglass-reinforced plastic
Other types
Body materials 3 - 3
2. Properties of metal
(1) Common properties
Iron and aluminum used to form shapes are called metals.
Metals have the following common characteristics. They:
• Shine when polished (metallic gloss)
• Are solid at room temperature (mercury is an exception)
• Have a crystalline structure when solid
• Are opaque
• Are very hard
• Have high tensile strength
• Have plasticity
• Are forgeable
• Are resistant to fatigue
• Have a positive atomic value (on their own they have positive ions)
• Have good heat conductivity
Specific gravity: Metals have a high specific gravity
Melting point: Although they are solid at room temperature (excepting mercury), they expand and melt when
heated. They turn into liquids. Melting point is the temperature at which this occurs.
Thermal conductivity: They conduct heat easily.
Conduction: They conduct electricity easily. Silver > Steel > Gold
Specific gravity
Melting point
°C
Thermal conductivity
0°C
Unit W·m-1·K-1
Electrical
conduction
0°C
Cu =100
Fe
7.86
1536
83.5
17.4
Aluminum
Al
2.70
660.37
236
62.0
Zinc
Zn
7.13
419.6
117
28.1
Copper
Cu
8.95
1084.5
403
100
Silver
Ag
10.49
961.93
428
103.4
Gold
Au
19.32
1064.43
319
76.0
Lead
Pb
11.36
327.5
36
8.1
Nickel
Ni
8.90
1455
94
24.8
Tin
Sn
7.30
231.9681
68
15.5
Metal
Chemical
symbol
Iron
* Values differ slightly depending on the source.
Body materials 3 - 4
(2) Mechanical properties
When metals are used for body materials their mechanical properties are checked.
1) Strength and hardness
Strong metals are those that have high resistance when pulled, compressed and bent. The surface of a hard metal
is not damaged when load is localized. Steel is the strongest metal, lead is the weakest.
2) Ductility and malleability
Ductility is a metal's ability to be drawn or stretched, and malleability is a metal's ability to be shaped or bent.
Together ductility and malleability are called forgeability. This is also called plasticity. Steel, aluminum, copper
and nickel have this property.
3) Brittleness and toughness
A brittle material bends and breaks easily. A tough material is strong. Cast iron is brittle and steel is tough.
3. From iron to steel
Sheetmetal is made by rolling steel into thin sheets. Steel is made by melting iron ore, the raw material, and
removing or adding elements after the iron is separated. Iron itself is hard to use as it is brittle when hard.
Steels with a variety of characteristics can be made by adjusting elements besides iron. Carbon is an important
element, and the more carbon is added the harder the material. There are different categories of carbon steel
depending on the amount of carbon added, such as soft steel and hard steel.
Other elements added to steel besides carbon (C) are silicon (Si), manganese (Mn), potassium (P), and sulfur
(S). Although they are added in small quantities, they make a difference to the properties of steel. They generally
increase strength, but steel can become brittle if large quantities are added.
n Iron and steel
n Types of steel
Carbon content
Carbon content
Iron
to 0.035 %
Soft steel
0.12 – 0.20 %
Steel
0.035 – 1.7 %
Hard steel
0.50 – 0.80 %
Cast iron
From 1.7 %
Tool steel
Over 0.5 %
Low-carbon steel
Less than 0.3 %
High-carbon steel
OVer 0.6 %
Body materials 3 - 5
(1) Sheetmetal manufacturing process
Steel is an alloy made by adding carbon to iron. It is easier to mass produce compared with other metal materials,
is inexpensive, and steels with a variety of properties can be made by adjusting the content of other elements and
by heat treatment. Steel that has been rolled into sheetmetal is highly formable and because it is inexpensive it
is used in a wide variety of fields in addition to automobiles.
Sheetmetal is produced by the following process.
n Sheet steel manufacturing process
Iron ore
Limestone
Coke
Ingot
Shaft
furnace
Iron
manufacture
Slab
Steel-making
Heating furnace
Ingot making
Hot rolled
sheetmetal
Hot rolling
Blooming
Cold rolled
sheetmetal
Cold rolling
1) Iron manufacture
Iron is removed from iron ore. Iron does not exist on its own, but is found in compounds, such as ferric hydroxide
(red rust Fe203) and triiron tetroxide (black rust Fe304 = magnetic iron ore). Only iron is separated by removing the
oxygen and others from iron ore which has a high iron content. Steel is produced by removing other impurities
as well.
2) Steel-making
Raw iron has many impurities, and because it is hard and brittle it is not used very much. Steel with various
properties is produced by removing impurities from the iron and adding necessary elements.
3) Ingot making/Blooming
Steel is cast by pouring melted steel into casts (ingot making) and rolling it into thick sheets (100 – 300 mm thick,
blooming) while it is being heated. These sheets are called slabs.
4) Hot rolling
The slabs are heated, ferric oxide is removed from the surface, and the slab is rolled once into a thickness of 25 –
40 mm, the surface is cleaned once more and the steel is rolled into the required thickness. This is how hot rolled
sheetmetal is made.
5) Acid cleaning
Ferric oxide is removed from the surface of hot-rolled sheetmetal by washing it off with acid.
Body materials 3 - 6
6) Cold rolling
Cold rolled sheets are made by rolling steel to the required thickness at room temperature.
7) Annealing
The structure within the steel which changes during rolling is heated to between 650 ˚C and 700 ˚C to get rid of
distortion.
8) Temper rolling
Surface finishing is done by lightly rolling the surface. This completes the steel sheet manufacturing process.
4. Types of sheetmetal
(1) Hot-rolled and cold-rolled sheetmetal
Sheetmetal rolled at temperatures between 800 – 900 ˚C is called hot-rolled sheetmetal. Hot-rolled sheets that are
rolled once again into thinner sheets at room temperature is called cold-rolled sheetmetal. Most sheetmetal used
in automobiles is cold-rolled. This is because compared with hot-rolled sheetmetal, À it can be rolled to thinner
thicknesses, Á it has a clean surface, Â and has good workability.
n Types of sheetmetal
Hot rolled sheetmetal
Sheetmetal for
automobile use
Cold rolled sheetmetal
Classification according to
manufacturing method
General sheetmetal
High tensile
strength sheetmetal
Classification according to strength
In the Japanese domestic market, sheetmetal is classified according to the following categories under Japan
Industrial Standards. Please refer to the corresponding standards for each country as required.
1) Hot-rolled sheetmetal
JIS No.
Name
Code
Remarks
G3113
Hot-rolled sheetmetal for use in
automobile structures
SHPH310/370/400/440
Sheet thickness 1.6 – 14 mm
G3134
Workable hot-rolled high tension
steel for automobile use
SPFH490/540/590
SAPH540Y/590Y
For forming
* Figures denote tensile strength. 310 is a minimum strength of 310 MPa.
2) Cold-rolled sheetmetal
JIS No.
Name
Code
G3141
Cold-rolled sheetmetal
SPCC, SPCD, SPCE
G3135
Workable cold-rolled high tension
steel for automobile use
SPFC340/370/SPFC390/440/490/540/590
SPFC490Y/540Y/590Y/780Y/980Y
SPFC340H
Remarks
C is for ordinary use
D is for drawing
E is for deep drawing
For drawing and forming
For forming
Low yield ratio type
Bake hardening type
* SPCD and SPCE have a minimum tensile strength of 270 MPa, and they are stretched 34 – 43 % depending on the thickness of the
sheet. As a general rule, SPCC is not tested for tensile strength unless a request is made by the customer.
* The figures for high tension steel denote tensile strength. 340 is a minimum strength of 340 MPa.
Body materials 3 - 7
(2) Corrosion resistant sheetmetal
When iron is left on its own, it combines with the oxygen in the air, forming rust (ferric oxide) on the surface.
When it is left even longer, the rust gets into the inside, making it brittle. It is for this reason that sheetmetal
resistant to rust is made by zinc plating the surface.
Different types from a wide range are used depending on the model and part of a vehicle. The main types are
shown below.
1) Hot-dipped sheetmetal
Sheetmetal is plated by dipping it in molten zinc. This is
called hot-dipped sheetmetal. By immersing the sheetmetal
n Dual layer alloyed hot-dipped zinc-plated
sheetmetal
in molten zinc, a zinc layer adheres to the surface.
Rather than a zinc layer on the surface that has high purity,
dual layer alloyed zinc-plated sheetmetal that has two
layers of a zinc and iron alloy is most commonly used. This
is because it has superior weldability and paintability.
Making an alloy that contains iron by making an alloy
layer that is 90 % zinc and 10 % and overlaying it with an
Double-sided specification
alloy layer that is 80 % or more iron enhances paintability.
Both paintability and corrosion resistance are provided by
creating a zinc-plated layer containing a lot of iron and an
inside with a lot of zinc.
Some corrosion-resistant sheetmetal is zinc-plated on one
side only, while some is zinc-plated on both sides. When
using sheetmetal plated on one side only, it is usual for the
plated surface to be facing the inside of the body.
2) Corrosion resistance and handling
Sheetmetal is made corrosion-resistant by first covering it
with a layer of zinc-plating, which prevents direct contact
with the air, thus making it difficult for rust to form.
n Uses of zinc-plated sheetmetal
Next, if zinc and iron are present under the same conditions,
the zinc will rust while the iron will not. Zinc rust does
not penetrate as deeply as iron rust, and because it stops
after forming a thin layer on the surface the rust will not
penetrate the sheetmetal.
Zinc and paint have poor adhesion.
When the paint layer is removed by sanding when making
repairs, the zinc-plated layer also comes off, exposing the
surface of the sheetmetal. This renders the sheetmetal the
same as untreated sheetmetal. But there are occasions
when paint adhesion can deteriorate because the plated
layer remains on feather-edged areas. However, paint
used for repairs today is made to cope with zinc-plated
sheetmetal so repair work can proceed as normal.
However, the removal of the zinc-plated layer means that a
vehicle no longer has the corrosion resistance it had when
new. Consequently, meticulous rustproofing should be
done prior to painting.
Sheetmetal on which
both sides are zinc-plated
Body materials 3 - 8
(3) High tension steel
Sheetmetal usually has a tensile strength of between 275 to 294 MPa (28 – 30 kg/mm2). Sheetmetal that has a
much higher tensile strength is called high tension steel. It has a tensile strength of between 390 to 490 MPa
(approx. 40 – 50 kg/mm2), or higher. High tension steel with a strength of 980 MPa (100 kg /mm2) is not unusual.
Sheets with a strength of 780 MPa or higher are called ultra-high tension steel.
High tension steel is made by adding minute quantities of other elements to standard sheetmetal. There are
various types depending on the elements and production methods used.
1) Solid solution-strengthened sheetmetal
The sheetmetal is strengthened by adding carbon (C), silicon (Si), manganese (Mn), phosphorus (P), etc.
2) Precipitation-strengthened sheetmetal
Titanium (Ti), niobium (Nb), vanadium (V), molybdenum (Mo) etc are bound to carbon (C) and nitrogen (N), and
added as minute elements to strengthen steel.
3) Compound structure sheetmetal
This is also called dual phase sheetmetal. The steel is strengthened by using heat treatment to alter the internal
structure.
When temperatures of above 700 – 800 ˚C are applied to precipitation-strengthened and compound-structure
sheetmetal, the internal structure alters and strength is reduced. It has to be heated to correct this deformation.
The adoption of high tensile sheetmetal has increased since around the time of the second oil crisis in 1979 as
a means of improving fuel economy and reducing vehicle weight. Since it has high tensile strength and a high
elastic limit, thin sheetmetal maintains the same strength as standard sheetmetal. Accordingly, when it is used
for body panels it is thinner than standard sheetmetal.
(4) Vibration damping sheetmetal
Vibration damping sheetmetal is made by putting plastic
between two sheets of sheetmetal. This type is also called a
Sheetmetal
sandwich sheetmetal panel. It is used for the toeboard, etc
PP, nylon, asphalt sheet, etc
because the middle plastic layer absorbs external vibrational
Sheetmetal
energy. It also reduces noise.
Body materials 3 - 9
5. Sheetmetal characteristics
(1) Plasticity and elasticity
When sheetmetal deforms due to the loading of force, deformation
occurs in two ways. There is deformation that is recoverable when the
Elastic
deformation
force is released and deformation that is not recoverable.The recoverable
type is called elastic deformation and the unrecoverable type is called
plastic deformation.
Only elastic deformation occurs when the force loaded to sheetmetal is
weak. The amount of deformation increases in proportion to the amount
of force that is loaded. Plastic deformation occurs when the force
Plastic
deformation
exceeds a certain level. When loaded force exceeds the elasticity of the
sheetmetal, the degree of force at this point is known as the elastic limit.
This is because creep occurs in the sheetmetal's internal structure.
When even more force is loaded, plastic deformation becomes greater
and the internal structure of the sheetmetal fractures. The force at this
point is the sheetmetal's tensile strength.
When force greater than the elastic deformation of sheetmetal is
loaded, both plastic deformation and elastic deformation occur. When
the externally loaded force is released, parts with elastic deformation
return to their initial shape, while parts with plastic deformation will not
return to their initial shape. When a panel is deformed in an accident, for
example, plastic deformation and elastic deformation occur. Depending
on the state of deformation, in many cases there is plastic deformation
which constrains the recoverability of the elastic deformation. At such
times, elastic deformation will naturally recover if the part with plastic
deformation is repaired.
(2) Work hardening
When sheetmetal undergoes plastic deformation, it will become harder
and its strength increases. This is known as work hardening. When body
panels are made, the steel is work hardened using press forming. This is
Work hardening
because exterior panels have an extremely thin thickness of 0.6 – 0.8 mm,
and the required strength cannot be obtained without this process.
Work hardening also occurs in panels that have been deformed in an
accident. Consequently, if force to recover its shape is loaded incorrectly,
all that happens is that other parts will become deformed and the
Effect
Before pressing
After pressing
deformed parts will not recover their initial shape.
If heat above a certain temperature is applied to a work hardened area,
the hardness created through the process will be eliminated and the
area will return to its original elasticity. This is known as annealing. If
areas that have work hardened and have become difficult to repair are
heated with a torch they will become soft and will be easy to return
to their original shape. However, the heat fractures the metal's internal
structure, which will mean that the sheetmetal used in the body has
considerably lower strength. Accordingly, as a basic rule members in
underframe areas that ensure the body's strength and other welded
panels must be repaired using annealing.
Even for a thin plate that easily undulate
when applying force while it is left flat,
if the press line is added, the line
section will be work hardened and will
have the same effect as inserting
reinforcing members
Body materials 3 - 10
(3) Work hardening of panels
Work hardening is used to increase the strength of panels. There are the following types of press lines that bend
panels.
1) Flange
A flange is an edge that projects at a right-angle from a beam-like member where
there is an angle bend. An example is the end of the front fender which has been
bent at a right angle.
2) Channel
As the name suggests, this has a U shape, and is seen in processing of side frames.
3) Box
For underframe areas like side sills and pillars that require high strength, two
U-channels are joined together to form a box.
4) Beading
Beading is the formation of a step in the middle of a panel to create a dent (or bump)
to reinforce a flat panel such as the floor pan.
5) Hemming
The edge of an area where an outer and an inner panel are joined is pressed so that
the outer side is tucked over the inner side. This method is used for the edges of
doors and the hood.
6) Crown
Low crowns are often used in the roof, hood, and fender because of their design, but
due to their low strength, they are combined with a high crown or a reverse crown
in order to maintain strength.
The different types of crown are the reverse crown, the low crown (low curvature)
and the high crown (high curvature).
Body materials 3 - 11
(4) Tensile strength
Strength and rigidity have different meanings.
Strength is resistance to outside forces, such as pulling, compression and bending, in other words break-proof,
and is largely used in connection with materials. Since it is the amount of force that can be withstood, it can be
evaluated using figures from objective measurements.
In contrast, rigidity is an abstract term that refers to how something holds together. It is mainly used in connection
with fabricated items. A material maintains the same strength no matter what kind of part it is, but its rigidity
changes depending on the shape that is made and how it is combined.
One indicator of the strength of sheetmetal is tensile strength, which is mentioned in the previous chapter on
types of sheetmetal. Tensile strength is measured by putting a thin long sample in a tester and pulling on both
ends and seeing at what force the sample breaks.
The relationship between load (force) and the amount of deformation (pull) changes as shown in the graph.
Although when sheetmetal is pulled it stretches slightly in proportion to the force, from a certain point this will
decrease and it will reach its elastic limit. When force is re-loaded, it will stretch to its upper yield point, stress
will decrease, it will continue stretching irregularly until it reaches its lower yield point, when stress and pull will
increase and it reaches its maximum stress point. This point is its maximum tensile strength. From this point only
stretching will increase and it will break.
The figure showing tensile strength is calculated by dividing the maximum load N (B in the graph) by the crosssectional area (mm2) of the sample.
While elasticity, plasticity and work hardening are common sheetmetal properties, in this graph plastic deformation
is reached when force exceeding the elastic limit is loaded. Even when the force is removed, the area that has
deformed will not recover its original state.
Conversely, when force below the elastic limit is removed, the sheet will recover its original shape as soon as the
force is removed.
The line shown in this graph applies to all sheetmetal. In the case of high tension steel, for example, the elastic
limit will be at a much higher force so this whole line will move further up to the right in the graph.
n Tensile strength and elastic limit
B. Maximum stress point
(maximum tensile strength)
A. Elastic limit
(elastic limit point)
C. Breaking point
Upper yield
point
Lower yield point
Load
(force)
Proportional limit
Deformation (pull)
Body materials 3 - 12
6. Aluminum alloys
(1) Types and characteristics
Aluminum is also used in auto body panels. Because aluminum weighs about a third of iron per cubic volume
(specific gravity), it weighs approximately half that of iron with the same strength. It is also rust resistant and
has good workability. It is used as an alloy which contains other metal elements. Because its properties such
as thermal and electrical conductivity make it different to sheetmetal and it also has a different hardness, it is
handled differently when used to make repairs.
Aluminum's appeal lies in it being the lightest material. It can be welded because of its thermal conductivity,
which is around twice that of iron. It is used in auto body panels and mechanical parts, but it is expensive. Like
iron it exists in the natural world combined with oxygen, because they are bound firmly the manufacturing
process consumes a huge amount of electricity.
Because pure aluminum is soft other elements are added to make an alloy, heat-treated aluminum, magnesium and
silicon alloys (6000 series) are the main alloys used in exterior body panels. Aluminum has excellent weldability
and corrosion resistance. There is also non heat-treated aluminum and magnesium alloys (5000 series) which
have excellent workability.
Aluminum is also rust-proof. With a melting point of 660 ˚C, it is lower than iron's melting point of 1,536 ˚C. But
because its tensile strength lowers when it is heated, care is required. Even though it is light, its low tensile
strength means that thicker panels are used.
It's a good idea to have an understanding of these characteristics when repairing aluminum alloy panels. Due to
its low specific resistance, it is difficult to weld a stud with a conventional stud welder. The surface of aluminum
is easily damaged and attention also needs to be taken with welding and painting.
n Differences between iron and aluminum
Comparison with iron at 1
Aluminum
Remarks
Melting temperature
0.4
Melts without becoming red hot
Weight per same volume
0.34
Weighs approx. one third
Thermal conductivity
1.75
Has nearly twice the thermal conductivity
Electrical conductivity
1.9
Has nearly twice the electrical conductivity
Body materials 3 - 13
7. Plastic
Parts made from plastic are used for a variety of parts, including the bumper face. It's necessary to know the
properties of the plastic used for each site and to take them into account when making repairs. A special kit can
be used when filling welds, patches and dents with putty. Do not use a hammer. It's more common for this to be
done by those responsible for painting.
There are natural and synthetic plastics. Petrochemical synthetic plastics are used for automobiles. There are
thermoplastic and heat curable synthetic plastics. These have different properties.
(1) Types and characteristics
1) Thermoplastic plastics
Thermoplastic plastics become soft when heated. They return to their original state when the temperature is
lowered.
À Polypropylene (PP)
Has a light specific gravity and excellent strength, rigidity, thermal resistance, electrical properties, water
repellency and chemical resistance.
Uses: Bumpers, headlamp housing
Á Polyethylene (PE)
Has excellent transparency, chemical resistance and electrical properties. Has poor strength, rigidity and thermal
resistance.
Uses: Mudguard, air flap
 Polycarbonate (PC)
Has excellent impact resistance, thermal resistance and weather resistance. Has poor fatigue strength.
Uses: Headlamp lenses
à Acrylic (PMMA)
It has high transparency, which is why it is used for paints. Also has good strength and workability. Is sensitive
to impact or organic solvents.
Uses: Lamp lenses
Ä ABS
Acrylonitrile butadiene styrene. Has good formability, but has poor thermal resistance and weather resistance.
Uses: Front grill
2) Heat curable plastics
When moulded and hardened at high temperatures, heat curable plastics will not soften if heat is applied.
À Polyurethane (PUR)
Has excellent elasticity, wear resistance and oil resistance, but is not very resistant to acids or alkalines.
Uses: Also used in paints and adhesive materials. Is used in foam form as a heat insulating and sound proofing
material.
Á Unsaturated polyester (UP)
Has excellent strength, rigidity and electrical properties. Has poor contractility and thermal resistance.
Uses: It is used in fiber-reinforced plastics.
Body materials 3 - 14
 Epoxy
Has good strength and electrical properties, but has no elasticity and yellows easily. It is also expensive.
Uses: It is a high-grade plastic used in fiber-reinforced plastics.
à Fiber-reinforced plastic (FRP)
FRP is made by impregnating unsaturated polyester with glass fibers to attain a high strength. The strength is
increased if carbon fibers are used. (CFRP).
Uses: Body panels
(2) Plastic body parts and materials
(8)
(8)
(9)
(9)
(6)
(6) (7)(7)
(20)
(4)
(11)
(10)
(5)
(12)
(3)
(2)
(1)
(13)
(19)
(15)
(15)
(21)
(21) (16)
(17)
(18)
(18)
(14)
Body materials 3 - 15
n Examples of plastic parts and materials
Number
1
Headlamp
Part name
Material
Lens
PC
13
Front mudguard
Housing
PP
14
Back of air flap
Extension
PBT+PET
15
Rear bumper
Bracket (housing)
PP+GF40
16
Rear gate garnish
3
Front bumper
Face
PP
17
Backup lamp
Fog lamp cover
PP
Hook cover
PP
Center lower bracket
PMMA
ASA
Lens
PMMA
PP
Housing
ASA
Side bracket
POM
Reflector
PC
Corner bracket
PP+GF30
Reflex reflector
Body, side
PP
18
19
Rear combination lamp
Door handle
5
Front grille
ABS
6
Turbo grille
PA/PPE
7
Bonnet duct inner
PP+EPDM
8
Front window molding
PVC
20
Roof molding
9
Door mirror
Body
ASA
21
Rear gate opener switch
Inner cover
AES
Under cover
Outer cover
ABS
Splashboard
Mirror housing
PP
Rear wiper
Lens
Housing
12
Rear spoiler
ABS
Housing
Cowl
Side spoiler
PP
Lens
4
11
PE
PE
Front fog lamps (standard)
Side indicator lamp
PE
Air flap
Face
2
10
Body
PMMA
Standard model
Handle
PC+PBT
Smart opener model
Handle body
PC+PBT
Antenna cover
PC+PET
End cover
PC+PBT
PVC
PP+GF35
Body
PP
PP
Blade
PBT
PMMA
Arm
PET
PC
Arm cover
PBT
PP
Body
ABS
High mounted lens
PMMA
High mounted housing
ABS
n List of plastic reference symbols
Reference symbol
ABS
Name of material
Acrylonitrile butadiene styrene
Resistance to solvents Heatproof temperature
×
80
AES
Acrylonitrile ethylene styrene
×
80
ASA
Acrylonitrile acrylate
×
80
EPDM
Ethylene propylene diene monomer rubber
×
80
PA/PPE
Polyamide/polyphenylene ether
△
80 to 100
Polybutylene terephthalate
○
160
PBT
PC
Polycarbonate
×
120
PE
Polyethylene
○
80
Polyethylene terephthalate
×
180
Polymethyl metacrylate
×
80
Polyacetal
×
120
Polypropylene
○
80
PET
PMMA
POM
PP
PP-GF20
Polypropylene (containing 20% of the glass fiber)
○
–
PP-GF30
Polypropylene (containing 30% of the glass fiber)
○
–
PP-GF40
Polypropylene (containing 40% of the glass fiber)
○
–
PVC
Polyvinyl chloride
△
80
TPO
Thermoplastic olefin
△
80
Unsaturated polyester
×
90
UP
Body materials 3 - 16
8. Glass
Various types of glass are used for the front windshield, rear window and doors of automobiles.
Standard glass has had silicon (Si), soda (NaO2) found in ash and caustic lime (CaO) added to it. Colorless and
transparent, it is also resistant to acids and alkalines.
Using a safety glass in automobiles is obligated. Safety glass must not cause injury if broken and must enable a
certain field of view.
(1) Safety glass
There are two types of safety glass. There is reinforced
glass with increased strength and laminated glass
designed to lower danger when it breaks.
Reinforced glass
Safety glass
Laminated glass
1) Reinforced glass
Reinforced glass is used in doors and for the rear
window. It is made by heating sheet glass to around 600
˚C and then cooling it rapidly. Glass breaks due to tension
upon impact. But because with reinforced glass high
compression force is locked inside it is extremely hard
to break. It has between three to five times the impact
Compression stress against
the impact is sealed in
resistance of ordinary glass. It can also withstand huge
differences in temperature.
If it does break, it breaks into many round fragments.
There is also reinforced glass that will maintain a certain
field of vision even when broken.
2) Laminated glass
The use of laminated glass for windshields has been
mandatory since 1987. Laminated glass has a thin robust
plastic membrane sandwiched between two sheets of
glass. When broken it does not fragment but stays in
one piece, allowing visibility. It also makes it difficult for
objects to penetrate the windshield.
Laminated glass with a thick layer in the middle with
high impact resistance is called HRP laminated glass.
The intermediate membrane made
of polyvinyl butyrate is sandwiched
between two sheets of glass
Body materials 3 - 17
(2) Special glass
It is common for additional functions to be added to glass used in automobiles.
There is laminated glass that has antenna wire integrated in the middle layer, tinted glass where a tint has been
added at the top of the middle layer, tungsten heating wires embedded in middle layer to prevent fogging and
mist, and glass that stops ultraviolet rays.
Types of reinforced glass include heat-absorbing glass that absorbs infrared rays which is made by added minute
quantities of metal elements, glass that absorbs and blocks ultraviolet rays, heat-reflecting glass, heat ray printed
glass printed with an electrically conductive paint, and tinted glass to lower transparency and improve privacy.
(3) How to distinguish different kinds of glass
At the bottom of automotive glass there is the JIS mark as
well as the name of the glass manufacturer and symbol
n Glass symbols
denoting the type of glass.
You can distinguish different types of glass from the
symbols found below the JIS mark.
L Õ Laminated glass
T Õ Reinforced glass
Z Õ Partially reinforced glass
P that denotes types is
an additional symbol
Body materials 3 - 18
Repair procedures 4 - 1
Chapter 4 Repair procedures
Contents
1. Order of tasks ................................................................................................................................................. 2
(1) Panel beating . ........................................................................................................................................... 2
(2) Painting ...................................................................................................................................................... 2
(3) The line between panel beating and painting . ....................................................................................... 2
2. Damage analysis ............................................................................................................................................ 3
3. Preparation ..................................................................................................................................................... 3
4. Removal of parts ............................................................................................................................................ 3
5. Underframe repairs . ...................................................................................................................................... 4
6. Replacing welded parts ................................................................................................................................. 4
7. Panel beating exterior panels ........................................................................................................................ 4
8. Painting ........................................................................................................................................................... 4
9. Fitting parts .................................................................................................................................................... 4
10. Completion checks . ..................................................................................................................................... 5
Repair procedures 4 - 2
1. Order of tasks
Damage caused in an accident varies and damage
will always be different even in the same kind of accident. However, there is a standard order in which to
Work
procedure
Summary
make repairs which can be followed for all types of
vehicle damage.
Repair work is broadly divided into panel beating and
Damage
analysis
Analysis of the accident conditions
Diagnosis of the damaged sections
Measuring body
Preparation
Examining/determining repair
procedure
Selecting body repair equipment
Removal of
parts
Examining removal/fitting area of
the related parts
Man hour for removal and fitting
Underframe
repairs
Fastening with the body repair
equipment, measuring, pulling
Basic repair of underframe of the
inner plate
Application of repair equipment
Replacing
welded parts
Removal/welding method of
welded parts
Replacement parts
Judging whether to replace
security parts
Panel beating
exterior panels
Welding point/bolt-on parts
Work method and man hour
Linking with painting process
Repair and
paint
Restoring the surface
Restoring painted colors
Maintaining the quality of the
paint film
Fitting parts
Check the construction
Completion
checks
Appearance
Wheel alignment
Wiring inside the engine room
Water leak
Operation/driving
painting.
(1) Panel beating
Panel beating is the task of using various tools and
machines to restore deformed panels, the body and
members to near original condition. It involves replacing panels that cannot be restored or which will
require too much time as well as replacing damaged
suspension, engine and other parts with new ones.
In the narrow sense of the term, panel beating refers
to the repair of panels only.
(2) Painting
Painting is the task of painting restored panels and
new parts so that they look like new. When panel
beating has been completed the quality can vary
depending on the skills of the worker and methods
used, but they never really return to their pre-damage
state. Some surface scratches are also left by panel
beating. In such cases, a primer coat is applied to the
substrate to prepare the surface for spray painting
with a top coat the same as the body color.
(3) The line between panel beating
and painting
The line between panel beating and painting differs
from workshop to workshop. In cases where machines and tools are used to repair panels only, a
panel beater does the work up to the point just before
the painting of the top coat. In some cases the line is
drawn before the painting of the primer coat.
In general, it is common for a panel beater to be in
charge of work up through the sanding of body filler
to create a smooth surface.
In some cases the work is divided into the three tasks
of panel beating, painting and the substrate, and in
some cases no distinction is made between panel
beating and painting. In such cases the aim is to acquire skills so that the same person is able to work on
every stage.
Repair procedures 4 - 3
2. Damage analysis
Analyze the circumstances surrounding the cause of the damage before deciding on the order of repair tasks.
• Where there has been an accident, this includes the shape and rigidity of the object the vehicle crashed
into, relative speed, angle, etc.
• Impact entry site and direction
This information is used for considering the extent of the damage and the direction in which to pull out the damaged part.
Measure the extent of the damage and amount of deformation.
3. Preparation
Draw up a plan based on damage analysis information.
1) Decide the order of tasks
The general method is to repair the underbody and work upwards to the upper body.
Where a car is damaged in a longitudinal direction up to the passenger compartment, the general rule is to take
precise measurements starting with the passenger compartment and working out to the front, or the rear.
2) Decide whether to repair or replace
The decision on whether to repair or replace varies depending on the type of panel to be repaired, role, extent
of damage, repair site, technology, and workshop policy. Although a decision taking all factors into account is
required, opt for repair if the cost of repairs falls under 70% of the cost of replacement.
3) Select repair equipment
Once you have made basic decisions such as confirming the extent of the damage and deciding whether to repair
or replace the damaged section, you will need to select the equipment to use for the repairs. Equipment ranges
from simple through to embedded systems. There are three fixed methods that use floor, platform and jig systems, and setting and resetting time also varies. An effective way to repair small and medium size damage is to
use a floor system that is easy to set.
4) Gather and check model information on body structure, etc
Gather information about precautions concerning repair sites by getting materials such as body repair manuals.
4. Removal of parts
First wash the car to remove dirt and dust and then start repairs from the step required according to the extent
of the damage.
Remove damaged parts that are bolted on, parts that need to be removed in order to repair or remove damaged
parts, and interior parts that will affect the repair work.
It is common to remove welded parts at a later stage while making repairs to the underframe.
Repair procedures 4 - 4
5. Frame repairs
Set up body repair equipment. Also measure the dimensions of each site while referring to drawings of body
dimensions and check the extent of the damage. Using your measurements, pull out the necessary amount of the
damaged site and restore it to its original dimensions. Even if there are welded panels that need replacing, leave
them and carry on with repairing the car body. This body repair work is known as body alignment.
6. Replacing welded parts
When each part has been restored to its original dimensions, cut out the welded parts that are to be replaced.
Remove by cutting along the original weld lines.
Tack new panels to the body and make tiny adjustments to the body by pulling using repair equipment. Also attach external parts and check the gaps between the panels. Weld the replacement parts when they fit neatly to the
body. This completes repair work done using body repair equipment.
7. Panel beating exterior panels
Damaged panels that are not replaced are repaired by removing surface paint and then using methods such as
beating with a hammer or pulling using welded washers or studs (pins). Depending on the site and extent of the
damage, bolt-on parts may be removed and then repaired.
8. Painting
The painting process consists of two main parts: the primer coat and top coat.
Tools used and the order of work for the primer process which follows body and panel repair differs from workshop to workshop. Basically there are two processes. One is applying putty to fill in deep damage and the other
is to fix tiny dents on the surface and use primer surfacer so that the top coat will adhere well. Sometimes the
extent of the damage requires the putty work stage to be done in two stages. Small dents on the primer surfacer
can be repaired using finishing putty.
Painting the top coat is an important process as it affects appearance after repairs have been made. The quality of
painting is greatly affected by the entire paint film (painting system), including the primer coat.
9. Attaching parts
Bolted on parts removed at the beginning are refitted when all stages are completed. Moldings and decals are
attached at this stage.
Repair procedures 4 - 5
10. Completion checks
Check the appearance of the car and the wiring inside the engine room. Check wheel alignment and whether the
various parts are functioning normally. If there are no problems, arrange for the car to be delivered to the owner
after cleaning the interior and washing the car.
Repair procedures 4 - 6
External panel repair 5 - 1
Chapter 5 External panel repair
Contents
1. Scope of deformation .................................................................................................................................... 2
(1) Types of deformation ................................................................................................................................ 2
(2) Washing and cleaning . ............................................................................................................................. 2
(3) Checking for dents and bumps ................................................................................................................ 2
(4) Distinguishing elastic deformation and plastic deformation ................................................................ 4
(5) Panel beating methods for different repair sites .................................................................................... 5
2. Hammering and pulling . ............................................................................................................................... 6
3. Massaging panels .......................................................................................................................................... 6
4. Pulling points, lines and planes .................................................................................................................... 7
5. Panel beating tools, machines and materials . ............................................................................................ 7
(1) Hammers ................................................................................................................................................... 7
(2) Stud welders ............................................................................................................................................. 9
(3) Pulling tools . ............................................................................................................................................. 9
(4) Towers, chain pullers, hydraulic rams ................................................................................................... 10
(5) Other related tools .................................................................................................................................. 11
6. Beating using a hammer and dolly ............................................................................................................ 13
(1) Principles of hammer and dolly repair . ................................................................................................ 13
(2) On-dolly and off-dolly hammering ........................................................................................................ 14
7. Pulling using a stud ...................................................................................................................................... 15
(1) Pulling tools . ........................................................................................................................................... 15
(2) Panel pulling steps . ................................................................................................................................ 16
(3) In combination with hammering ........................................................................................................... 17
8. Identifying damage patterns and repair work ........................................................................................... 17
(1) Identifying damage patterns .................................................................................................................. 17
(2) Wide mild deformation ........................................................................................................................... 17
(3) Small sharp-angled deformation . ......................................................................................................... 18
(4) Long thin deformation . .......................................................................................................................... 19
(5) Creases .................................................................................................................................................... 19
9. Shrinking sheetmetal .................................................................................................................................. 20
(1) Causes of stretching ............................................................................................................................... 20
(2) Detecting and preventing stretching ..................................................................................................... 20
(3) Principles of shrinking ............................................................................................................................ 22
(4) Order of tasks .......................................................................................................................................... 23
External panel repair 5 - 2
1. Scope of deformation
(1) Types of deformation
Body panels deform when they receive an impact. Dents are caused, but they are not the only sites where deformation occurs. There are cases where deformation occurs at sites away from the point of impact entry. This
depends on the direction of the impact, site, and degree of force.
This type of deformation is called indirect deformation or secondary deformation. Deformation caused at sites
that received direct impact is called direct deformation or primary deformation.
It is common for indirect elastic deformation caused as a result of an impact to occur at sites that are fixed to
the damaged point of impact. Consequently, this deformation will naturally return to its original shape when
the main deformation is restored. Inadvertently restoring the damage starting with the indirect deformation will
make restoration more difficult as it could require stretching panels. To do the work efficiently in a short period
of time it is important to follow the correct order based on an accurate assessment of the type and state of the
damage.
n Types of deformation
Direct deformation
Indirect deformation
(Elastic deformation)
(2) Washing and cleaning
It is vital to wash the vehicle before starting work. Wash the entire body. Pay particular attention to the damaged
site and surrounding area. It is hard to see the damaged site or determine the state of the damage if there is dirt
or mud on the vehicle. For this reason, clean the car by washing not only the body surface but also the other side
of the panels with water and remove any grease using a detergent. Wash the car starting at the top and work
down.
(3) Checking for dents and bumps
1) Visual check
If the paint film is not damaged, make a visual check
for any deformations by shining a light on the body
surface. They're easy to see if you leave some space
between you and the site you're checking. If there is
not much light, wetting the site with water is useful.
Sometimes they're easier to see if you change your position or angle and make a comparison. If right and left
have the same shape use the non-damaged side for
reference.
External panel repair 5 - 3
2) Hand check
When the deformation is tiny or you're nearing the finishing stage it can be extremely difficult to tell what has
been restored to its original shape and what hasn't.
With experience, you will be able to perceive tiny dents by running the palm of your hand or fingers over an area.
Standard practice is to do this with your non-dominant hand and to wear a thick cotton glove. The skin on your
dominant is thicker. Also, put a glove on it as well so you can't feel the temperature of the panel surface.
Run the palm of your hand from the probable deformation site outwards. Deformation is easier to detect if you
draw your hand away rather than drive it in. This is because detection is easier if you start low and move higher
rather than starting high and moving lower.
Feeling with fingertips
Easy to tell
Difficult to tell
Check with your non-dominant hand
3) Sand using a sander
If you use a disc sander or special paint removal sand-
Sanding mark will
be left clearly
er to lightly sand the deformation site the paint will
remain in low spots and most of it will come off in
raised spots. Even after the paint has been removed,
Paint film will be left
No sanding mark will be left
the size of the sanded area left on the metal section
of the panel will make it easy to see which parts are
raised and which are low. However, if you leave deep
sanding marks it will take time to fix it up later on.
Therefore, sand as lightly as possible using uniform
force across the entire area.
You can also use a file instead of a sander. If you file
lightly with medium grained file, filings won't adhere
to low spots.
4) Use chalk
Take chalk used to write on the blackboard, hold it
sideways and run it over the body. Normal parts will
color up while the color of the chalk won't stick to
dents.
There are other tools like straight-edges.
Chalk
Where the color
is not left is the
lower section
External panel repair 5 - 4
(4) Distinguishing elastic deformation and plastic deformation
When a panel receives an impact, the deformation that occurs is either elastic or plastic deformation. Although
normally when the force is unloaded (after the impact), parts where elastic deformation has occurred will return
to their original shape. However, plastic deformation which stops this from happening often occurs as well.
A good panel repair method is to use force that restores elastic deformation. In other words, do not work on parts
with elastic deformation and instead repair only parts where plastic deformation has occurred. If you do that
parts, then elastic deformation will automatically return to their original shape.
Accordingly, being able to distinguish between elastic deformation and plastic deformation is a requirement for
carrying out panel repairs efficiently.
The edge of elastic deformation is not obvious in a visual check, as panels deform on a relatively gentle incline.
Also, if dents are pushed from the rear, the deformation changes shape while moving the top of the panel.
In contrast, when there is plastic deformation you're most likely to find sharp angles and peeled paint. When you
push a dent from the rear, the deformed area will stay still while the surrounding panel surface will move.
n Deformation patterns and repair points
Wide mild deformation
Deformation in the form of creases
Long narrow deformation
In most cases, top and bottom
are plastic deformation while
left and right are elastic
deformation
L Deformation at the center of the panel
Plastic deformation
Elastic
deformation
Looks like being bent
Paint is peeled
It is easier to restore by
repairing only this part
L Deformation near the edge of the panel
Elastic deformation
Plastic deformation
Stretch by pulling from front
and back before repairing
Narrow sharp deformation
Large stretch of the sheetmetal generated
at the corner and other sections
Paint film around
the dent and inside
the dent are partially
peeled
Hammer while
force is applied
If pulled incorrectly,
surrounding area
will be lifted
External panel repair 5 - 5
(5) Panel beating methods for different repair sites
Hydraulic equipment is used when strong force is required for pulling, though most repairs to outer panels are
done manually.
Hammering, or tapping, is when a panel is placed against a dolly or body spoon and the deformation is repaired
by beating with a hammer. This requires you to be able to reach your hand round to the back or to insert a tool
instead.
In contrast, pulling is when a slide hammer (dent puller) or stud pin washer welder (sometimes this is simply
called a stud) is used to repair the panel by pulling it out.
There are different types of pulling. There is vacuum pulling where suction is used, pulling that uses clamps, pulling that uses a slide hammer with replaceable head attachments for different sites, weld pulling that uses plastic
tools as well as studs.
Small dents are also massaged by inserting a tool in the gap and massaging the dent from the rear.
Choose the most appropriate method depending on the site of the panel damage, and where necessary use a
combination of methods.
n Panel beating methods
Sheetmetal
work
Hammering
With hydraulic equipment, etc
Beating
Hammering, beating out
Pulling
Suction, hooking, clipping, welded
Dinging
Dent
1) Ends of panels with openings: Wheel arch
Deformations at the ends of panels like the wheel arch which has an opening can be pulled by attaching a hooktype attachment to a slide hammer. Of course, this can also be done by normal washer pulling, and because you
can reach your hand in behind you can also beat the deformation.
2) Repairs that can be made from behind: rear quarter panels, etc.
At some sites like quarter panels, the hood and trunk lid, if you remove the trim you can reach your hand or a tool
around to the other side. Consequently, in addition to pulling you can also do planishing where you hammer out
the deformation.
3) Repairs that can only be done from the rear
Pulling is done when you can't do the work from the rear without removing the part, such as for welded parts like
side sills, doors and the middle of fender.
However, since it is easy to remove the front fender you can remove it to panel beat it by hammering.
External panel repair 5 - 6
2. Hammering and pulling
Pulling has the following advantages over hammer-
N Hammering
ing.
a. Because pulling is done from the outside, the work
can be done regardless of whether the other side is a
pouch structure or whether there's an obstacle in the
way. There is no need to cut the rear side or remove
and replace parts more than is necessary.
b. Hammer blows stretch sheetmetal. There is relatively little stretching when pulling. You can also get
away with doing a minimum of shrinking.
c. Work is fast because a large amount of force can
be applied if necessary.
d. By using a variety of tools and attachments you
can acquire the necessary skills in a relatively short
period of time.
3. Massaging
Although hammering and pulling are the two main
methods of panel beating, there is also massaging.
Dents are repaired by pushing them out from the
rear side of the panel. This is used for small dimples
like those caused by hail. Special kits of dent tools
are used for this process.
A thin long rod-like dent tool is put under the dent,
and the dent is massaged from the rear using the
rear panel as a fulcrum. This makes it possible to repair the dent without damaging the top paint.
Since the tools are inserted into the back of the panels, use the tool with the correct shape for the particular site.
There is a variety of other tools, including special
light sources for looking at dents, and magnets attached on the front side to make it easy to find the
exact spot.
N Dent repair tools
N Pulling
External panel repair 5 - 7
4. Pulling points, lines and planes
Simple damage caused by a single entry point can be repaired by pulling with the appropriate amount of force.
In reality, however, such simple damage rarely exists.
In principle, it is easier to pull a line than a point, and pulling a plane is even easier.
When pulling a point, depending on how much strength you use, you can pull too hard on just the point at the
center. If hammering of the surrounding area is neglected the deformation can become more complicated. There
is, therefore, a tool that is used like a lever so that by pushing down on the surrounding area the center is pulled
with a pinpoint.
For damage that runs along a line, there are also tools that will pull an entire long line. For planes there are pulling
methods where a plate is attached using a special solder.
5. Body repair tools, equipment and materials
(1) Hammers
1) Role of the hammer
The hammer is a tool that has come to symbolize body repair. However, in body shops today apart from the restoration of classic cars you won't find repairers using hammers and dollies to beat panels of every conceivable
shape to restore them to their original contour as was the case some years ago. The reasons include À advanced
technology is required; Á it takes time; and  the price of parts is relatively inexpensive and they're also easy to
obtain.
2) Hammers and related tools
The term hammering is used for various tasks performed using a hammer. There are a number of other tools
required for hammering and there are also different types of hammers. The main types of hammers are listed
below.
À Bumping hammer
The bumping hammer is indispensable for repairing panels. At one
end the face is a round flat striking surface while face at the other end
is thinner and slightly curved. The precision of the striking surface is
different from hammers used to hit nails. Do not use these because
they could leave a dent.
Although of a similar shape, those that are bigger are used for roughing out.
Á Shrinking hammer
The striking surface is cross-milled like a file, and when shrinking
stretched sheetmetal the hammer is used in combination with a dolly
with a similar type of surface.
 Pick hammer
A hammer with a thin sharp point. Used for repairing very small protrusions and dents.
External panel repair 5 - 8
à Mallet
A mallet is used to apply light force when you don't want to remove
paint or stretch the panel. The head is made of wood. Hammers with
a plastic head can be used for the same work.
In some cases you can get the same result by placing a small piece of
wood against the panel and beating a standard hammer against it.
Ä Dolly
A dolly is a block of metal that fits in the hand. A dolly is used to hold
the surface being hammered or a nearby site. A dolly can be used
instead of a hammer for places where a hammer can't reach. Choose
a dolly with a shape most suitable for the repair site.
Å Spoon, lever
A steel rod where either one or both ends have been shaped like a
thin spoon. A spoon can be used instead of a dolly to reach places
hard to reach with your hand. It can be used like a lever when making panel repairs. They come in a variety of shapes and lengths for
different sites.
A lever has an S shape and has sharper angles than a spoon, and has
bent tips.
Spoon
Lever
Æ Chisel
Although a chisel is usually used for cutting panels and removing
welds, chisels are used for beating press lines because of its wide
semi-cylindrical blade.
When chisels such as cold chisels are used the end is hit with a hammer. In such cases a bumping hammer must not be used.
Ç Center punch
A center punch is normally used to make a dent in the center so that
the drill blade does not slip when making a hole. In panel beating it
can also be used to hold down a high point. Unlike a pick hammer,
the repair site can be lowered without the center punch slipping off
the repair site.
Cold chisels
External panel repair 5 - 9
(2) Stud welder
Called a stud pin washer welder in full, the
name is often shortened to stud or stud
weld.
When this method of pulling was first develto gain leverage. Today, washers or shaped
washers are commonly used.
The principle is the same as that for a spot
Sheetmetal
oped, a thin rod, that is, a stud pin, was used
Main unit
welder. A weld is made with the resistant
heat generated when a strong current is discharged through a narrow area.Consequently, there are spot welders that can perform
Clamp for
earth
this function. Although stud welders are
commonly used because they are compact,
lightweight and simple, since a stud welder
does not have the power of a spot welder it
cannot make proper welds.
(3) Pulling tools
1) Slide hammer
Studs and slide hammers (dent pullers) are typical tools used for pulling. Force is applied by the reverse action
when the weight in the middle is moved.
Slide hammers come in a variety of lengths and with a variety of weights. Select a slide hammer according to
the site and extent of the damage.
Since the head is replaceable, you can choose the appropriate attachment for the job, such as a hook to pull washers and stud attachments and hooks that hook on to the end of panels.
If you use a stud puller with an electrode you won't need a slide hammer and stud, but it can only be used to pull
out one site.
External panel repair 5 - 10
2) Lever-type pulling rod
Clamp a stud pin or washer in the center, brace both sides or the
top of the circle and pull the lever. The metal is pulled out using the
principle of a lever. Because it makes it possible to use a point to pull
out only the corresponding surrounding surface it is a good method
for beginners. There are also air-powered pulling rods.
Hand-held type
3) Suction puller
Air-powered
type
A suction puller works by attaching a suction cup to the sheet metal.
When there is elastic deformation in doors and outer panels, a suction puller can be used to pull out and restore the shape of the surface quickly, providing the pull point is appropriate.
4) Hooks
Force can be applied to a panel using just the hand by hooking a
hand hook into a washer or a hole in the panel. Hand hooks are useful for repairing relatively light damage by hammering an area with
plastic deformation while pulling an area with elastic deformation.
(4) Tower, chain puller, hydraulic ram
A chain puller or hydraulic equipment is used not only for repairing the underframe, but also for repairing strong
areas in panels. They are used when manual force or a the force of a slide hammer is insufficient.
A tower is a simple type that does not have the power of a floor-type system and is used for pulling in combination with a chain puller or similar equipment.
However, when more force is used to repair a panel, it is also necessary to steady the body side. When using
manual force the weight of the vehicle on its own is sufficient. However, when using a hydraulic ram or a chain
puller, the pulling force can move the vehicle itself. As a result, the force is not used effectively and depending on
the direction it can be dangerous.
It's a good idea to use chains to stabilize the vehicle so that it won't move. Attach chains to strong areas of the
body, an attach them to floor rails or other solid fittings in the workshop.
n Hydraulic ram set
External panel repair 5 - 11
(5) Other types of related tools
Other tools and equipment required when pulling panels are shown below.
1) Disc sander
A disc sander is used for removing paint and sanding the metal surface
when work has been completed. Use paper with a coarse grit of between
P24 and 80.
There are single action sanders used specially for removing paint. Paint can
also be removed using a variety of other tools, including a sand blaster and
special plastic sanders.
2) Belt sander
Use a belt sander for removing paint from small dents and narrow areas.
3) File
Files used on metal are included in body repair tool kits. They are used more
to identify unevenness in panel surfaces than as a sanding tool.
4) Guide coat
A guide coat is back powder that is rubbed on the repair site or a black aerosol lacquer paint that is sprayed lightly on the repair site. Humps and dents
in the panel surface can be identified by sanding the surface once the guide
coat has dried.
5) Air duster gun, cloths, degreasing agents
These are used to clean the surface once work has been completed.
6) Metal surface (zinc phosphate) finishing agent
This one component type creates a thin zinc-plated layer on the panel surface. It is used for rustproofing when repair work has been completed.
The agent is diluted with water and brushed on, and is washed with water
when semi-dry.
7) Wash primer
This is usually a two component type, and is a metal surface finishing agent
with an added rustproofing pigment. It has much better corrosion resistance
and adhesion. Follow the instructions in the manual, as the contents vary
slightly depending on the manufacturer.
External panel repair 5 - 12
8) Putty
It's difficult to get a perfect panel by just pulling or hammering. Putty is used to repair tiny bumps and dents once
panel work has been completed.
Putty is used to attain the final surface, because in panel beating the surface is restored so that it is slightly lower
than the finished surface. It's common for panel beaters to also have to apply and sand back putty.
Putty is a primer coat used to fill dents. The filling depth and fineness of the material are in inverse proportion to
each other. Panel beaters use either a metal sheet putty or an intermediate type of polyputty.
Putty is mainly made up of an extender and a polyester resin in order to maintain its bulk. It reacts with a hardening agent and takes a short time to harden. The compounding ratio of hardening agent is 100: 2 – 3. Measure
using an accurate measuring apparatus.
n Types of putty and filling performance
Type
Filling performance
Surface condition
Main applications
Metal sheet putty
to 50 mm
Coarse
Deep dents
Sections subject to force
Intermediate type
to 30 mm
Fairly rough
Surface finishing
Polyputty
Thick
10 to 30 mm
Medium
5 to 10 mm
Smooth
Repair of puttied surfaces
Thin
to 5 mm
Extremely soft
Repairs of minor deviation
* These are general examples and values vary according to product
9) Types of sanders
Use a double action sander, orbital sander, straight line sander, etc for plane grinding the putty.
n Types of sanders
Double action sander
Long orbital sander
Short orbital sander
Straight line sander
External panel repair 5 - 13
6. Beating using a hammer and dolly
(1) Principles of repairing with a hammer and dolly
1) How to handle a hammer
The way you hold and beat a hammer when repairing panels is different from beating using a chisel. Even when
repairing panels, there are slightly different methods, such as roughing out, bumping and finishing.
The basic way to hold a hammer is to grip the end applying force with your little finger and gently holding it with
your fourth finger and middle finger. To stop the hammer from swinging sideways, lightly press your thumb and
index finger against the side. It is important not to grip the hammer too firmly. Grip the handle the moment you
hit the panel.
The basic rule when using a hammer is not to use force, but using your little finger as a fulcrum use the weight of
the head to make it fall naturally. Don't use only the power from your arm. Use power from the arm only to direct
the hammer. When beating repeatedly and fast, make fast snapping motions using your wrist as a fulcrum.
If the face of the hammer or the panel surface are at an angle you will make unnecessary marks on the panel.
The basic rule is to hit the panel with the face parallel to the panel. It is not so easy to make marks if the outer
perimeter of the panel is rounded.
Try to regulate the number of hits per unit of time and intervals as much as possible. If they become irregular,
unstable force will cause a not so good result.
To prevent the panel from stretching, don't continue beating the same spot numerous times.
Gently hold the end of the hammer handle and make snap motions
using your wrist
Hit the panel with the face parallel to the panel
External panel repair 5 - 14
2) Hammer care
Use wears down the face and causes marks, so make regular
There should be no
scratches or dirt
checks and remove dirt etc. Grind the face to tidy it up if there
is wear or marks.
It should be flat or
the central part
should be slightly
lower
Carefully grind the face using a flat file. Put it in a vice and file it
from different directions. When finished, plane the edges 1 – 2
This angle should
not be sharp
mm, and finish by sanding with P400 – 800 sandpaper.
Occasionally check the part where the handle and head are
joined and adjust so it doesn't rattle. If it is loose hammering
will become unsteady. It is even more dangerous if it comes
off.
3) How to use a dolly
Hold the dolly so all of it fits in the palm of your hand. Don't
grip it, but hold it gently.
N How to place an dolly
As with hammers, the surface of the dolly should always be
clean. Remove dirt etc when it appears.
(2) On-dolly and off-dolly
There are two methods of repairing using a hammer and dolly.
They are hammer on dolly (on-dolly hammering) and hammer
off dolly (off-dolly hammering). Use a combination of the two
methods.
1) On-dolly
On-dolly is when the panel is between the dolly and hammer.
The dolly absorbs the striking force of the hammer, and the
panel retracts a little from the dolly. By placing it up against the
panel again, it is struck from behind, so the panel becomes flat
with force from both sides.
2) Off-dolly
Off-dolly is when the hammer and dolly are not aligned at the
panel. Sometimes it is when the dolly strikes the panel from
behind. The further the distance between them, the weaker the
effect of the beating.
When repairing a panel, start with off-dolly and finish with ondolly. Take a careful look at the damage, envision what the finished product will look like and hammer methodically until you
arrive at something like the finished look. Continuing beating
just the dent with force won't restore the shape.
Select the shape that matches the panel
surface that is to be repaired
External panel repair 5 - 15
7. Pulling using a stud
(1) Pulling tools
1) Making something to gain leverage
When pulling a more or less flat panel you need something to grab hold of.
There are three methods: À Weld something on to the panel surface; Á Make a hole in the panel; or  Use a tool
that doesn't require something to pull on.
2) Welding on something to gain leverage
Washers, stud pins, thin sheetmetal, etc are common examples of things welded on. A dedicated
stud welder is used for washers and stud pins. The
washer (stud) is put in one of the electrodes, while
the other electrode is earthed. Dedicated or universal
slide hammers can be used to attach the washer and
Attaching washers
stud, but because with a stud there must be a structure to hold the pin, washers that can be hooked into
a hole are more versatile.
A number of washers or studs can also be welded
in a row. Connect them and apply force to the larger
area.
Although there are some special plate-shaped washers, they are usually used on the cut ends of assembled panels. They are attached using a MIG weld or
Attaching studs
soldering machine. They are particularly useful when
a lot of force is required. A clamp is attached and
they are pulled using a large slide hammer or a tower and chain puller.
3) Making a hole in the panel
This can be done by À pulling on a hook-shaped tool hooked into the hole; or Á using the tip of a slide hammer as
a drill to make a hole, which is then pulled. Although this is an easy way of getting something to hold on, the area
around the hole deforms needlessly and this takes time to repair. Also, if a hole is not filled adequately afterward
it may cause rust, and sometimes the putty doesn't adhere properly.
It's not suitable for areas where you can see the rear surface. It also gives the car owner a bad impression. Holes
were the common method used before pulling using studs began to be adopted in 1975. This method is hardly
ever used today.
External panel repair 5 - 16
4) Tools that don't require leverage
A suction puller that uses the power of a suction cup is a good example of this type of tool.
Other pulling methods include using a solder shaped like a hook or attaching a plastic rod that has been softened
at high temperature.
The stud puller mentioned earlier is a tool that uses this method. The tip adheres to the panel.
(2) Panel pulling steps
The basic order of steps for pulling a panel is shown as follows, though this can differ depending on the state of
the damage and the tools that are used.
1. Check the damage
Ascertain the scope of the damage, its relationship to other sections, the severity of the damage,
cause, etc. Mark the damaged section if necessary.
2. Remove parts
Remove pinstripes, lamps and other parts in the area to the repaired.
3. Roughing out
In cases of severe damage, return the press line or panel shape to as near as the original shape as
possible.
4. Remove paint film
Limit the removal of paint film to as small an area as possible required for attaching a washer, etc.
5. Attach an earth
To attach a washer, attach a minus electrode on the same panel as near as possible to the repair
site, or somewhere where it will not get in the way. First remove the paint from the spot where the
earth will be attached.
6. Repairing panels
Repair the damage using various panel pulling tools.
7. Fixing holes made in the body
When the repair has been made, if there are small holes left by washers, etc place MIG welder wire
(around 0.6 mm) up against the hole, and weld it on from above passing the current through the
stud. If once does not fill up the hole, do it a second time.
8. Checking the damage
Check whether the damaged panel has been finished to a level where body filling can be done. Also
check to see whether or not the sheetmetal has stretched.
9. Shrinking
If the sheetmetal has stretched, shrink as necessary.
10. Sanding the surface
Sand off traces of the washer on the panel surface. Also check for small marks.
11. Surface finishing
Rustproof metal surfaces using a zinc phosphate finishing agent or washer primer.
12. Applying putty
Apply metal sheet putty or polyputty, and sand when dry so that the surface is back like it was
before the damage.
External panel repair 5 - 17
(3) Combinations with hammering
Pulling alone is not sufficient to restore panels. Sometimes using a hammer is faster when roughing out. Even at
the panel repair stage, it can be quicker to hammer the surrounding area while maintaining pulling force, as this
will remove plastic deformation in the panel and restore elastic deformation.
When repairing a small deformation, it is sometimes simpler to use a hammer and dolly. Using appropriate combination of tools, mainly hammers, in this way is a way of shortening work time when repairing panels.
Also, the hammers used do not have to be metal (iron). In some cases mallets and plastic hammers are used to
beat lightly in order not to stretch the panel
8. Identifying damage patterns and repair work
(1) Identifying damage patterns
Panels are deformed in a variety of ways. A close comparison shows that no two shapes are the same. Though the
shapes might be different, the basic characteristics of damage are the same. Whether the damage covers a wide
or narrow area, has shallow or deep dents, and the number or size of creases does not really have much effect on
methods or order of repair work.
Damage manifests itself in different ways. A look at the types of damage while mindful of work order and methods in the course of everyday panel repair work, reveals there are surprisingly few different types of damage.
Identifying damage patterns allows individual deformations to be treated as variations of those patterns, which
makes it easy to draw up a work plan. It also shortens work time.
(2) Wide mild deformation
1) Characteristics
Wide mild deformation occurs
easily when a not very strong
Mild deformation
Rather than applying strong force, repair with gentle force
force is applied to panels with
near-flat wide surfaces. It is
mostly elastic deformation,
though partial plastic deformation prohibits the restoring
Partial plastic deformation
Deformation taking the form of a step
force of the panel.Plastic de-
Once the plastic deformation is
repaired, the entire section will
be restored
Rough out by applying force over wider area
and starting with off-dolly and then changing
to on-dolly hammering
formation is easily identified,
as sharp angled deformation
and peeled paint occur only in
those areas.
External panel repair 5 - 18
2) Repair work
Restoration is relatively easy because sheetmetal does not stretch very much. Basically, if those areas with plastic
deformation are repaired, the other areas will naturally regain their original shape. However, if a dent is formed
again when pressing lightly on the restored part, it means that the sheetmetal has stretched at the part where
there was plastic deformation. Shrinking then becomes necessary.
At the end of panels and at sites where there are reinforcements, the deformation takes the form of a step. When
the impact entry point is nearby, it is possible that box areas in panels will have stretched. For this reason, a
method that applies uniform force over a wide area should be adopted to prevent more stretching. One effective
method is to arrange a row of washers and pull out the panel.
(3) Narrow sharp-angled deformation
1) Characteristics
Stretching has already occurred in narrow sharp-angled deformation in high crowns, corners and highly rigid
panel surfaces and there is a risk that more stretching will occur during repairs. Even if you attempt to pull out the
center of the deformation, the deformation can easily bring the surrounding area up with it.
2) Repair work
Keep lifting in check by beating the surrounding area while pulling out the deformation. First pull with strong
force, and lightly beat the area that has lifted while maintaining that force. Be careful not to beat too hard as this
will cause the panel to stretch. Restore it slowly making sure not to reverse the panel's elasticity. This is done
faster by applying force from the edge, not the center of the deformation.
Deep dents
Shallow dents
After roughing out with a dolly and slide hammer, repair by hammering,
Either use a dolly from behind or pull out by attaching a washer, and
starting with off-dolly and then changing to on-dolly hammering.For pan-
hammer the surrounding area while retaining that force.When the defor-
els that have been pulled, hammer while maintaining the pulling force.
mation is reduced change to on-dolly.
External panel repair 5 - 19
n Width of a dent and how to apply pressure
Wide dents
Narrow dents
Pull out the whole dent using a slide hammer
Pull using the reverse movement of the weight
(4) Long narrow deformation
1) Characteristics
It is common for long deformation to be elastic deformation and
for short to be plastic deformation. Accordingly, don't apply much
Rough out first by pulling with stronger
force, and repair by hammering while
maintaining the pulling force
force to lengthy deformation (don't beat much with a hammer),
and repair the damage in the short direction.
Soldered thin plates or
connected washers
2) Repair work
Pulling requires a relatively large amount of force. Since working
from the center of the deformation will stretch the sheetmetal,
if the deformation is long repair it little by little from both edges
moving toward the center along the longitudinal direction of the
panel.
Conversely, if the deformation is short, working on parts will
Force is maintained
stretch the sheetmetal. Applying large force to the center of the
damage in short bursts will be quicker in some cases.
Large slide hammers,
chain pullers, etc
(5) Creases
1) Characteristics
This kind of deformation occurs when force is applied in a lengthwise direction to the panel surface. Although if
the damage is severe the panel should be replaced, restoring this damage is not as difficult as it looks. Because
all of it is compressed, apply force so as to stretch it to its original length.
External panel repair 5 - 20
2) Repair work
If this type of deformation occurs in a bolted on panel, repair will be
easier if the panel is taken off. If force is applied to stretch both ends of
Pulling from both ends to stretch the
creases and repair the deformation
while maintaining the pulling force
the panel it will regain some of its original shape. If force is removed
at this point, because it will shrink for a second time while deformed,
stabilize the shape by beating the sharp angled part.
Panels with this damage are perfect for practicing beating skills.
9. Sheetmetal shrinkage
(1) Causes of stretching
When comparatively soft metal like gold is beaten a number of times it will become thinner and its area will increase. This is called metal ductility.
Sheetmetal has the same property. As a result, when an impact or force is applied for making a repair, it will get
thinner and the area will increase. This is sheetmetal stretching. Because when part of a panel tries to stretch the
surrounding metal stays the same, it can't increase its area. As a result, that part of the sheetmetal becomes surplus. It changes from its original shape by rising a little and rumbles when pushed.
To repair the stretching, this part of the sheetmetal has to be shrunk. Shrinking is done by using the stretching
and shrinking of metal that occurs due to temperature change. It is an important task that has a huge effect on
the finished quality.
(2) Detecting and preventing stretching
Shrinking is a technically difficult part of panel repair. A damaged panel has varying degrees of damage and most
have a part that has stretched. In restoration it is necessary not to make the stretching any worse and to keep it
to a minimum. In details, À do not apply stronger force than necessary; Á when beating do not keep repeatedly
beating the same spot; Â and make the repair as simple as possible.
Often it is not possible to identify a stretched part from its appearance alone. In order to find the stretched part
either run your hand over the sheetmetal or press the metal with your fingers.
n Panel stretching
When force is applied to metal it stretches and expands
Even a stretched area that looks as if it has been
Hammering will stretch the sheetmetal
restored to its normal shape will rumble when
you run your hand over it.
External panel repair 5 - 21
1) Feeling by hand
Run the palm of your hand from the undamaged part of the panel over the part that has been repaired. The part
that has stretched will bulge slightly.
Sometimes parts along the press line or on the edges of a panel that have nothing to do with the repair will
bulge. This is caused by stretching of the part being repaired. This will naturally correct itself when the stretching
is fixed.
2) Pushing
Push the repaired part with your fingers. The biggest dent will be the center of the stretching. If the stretching is
severe it will make a rumbling noise.If all parts feel the same when pushed, it means there is no stretching.
If another site deforms when you push it means that the part that deformed has stretched.
External panel repair 5 - 22
(3) Principles of shrinking
Metal expands when heated and shrinks when cooled. Shrinking is applying this principle to sheetmetal that has
stretched.
When stretched metal is heated the hot sheetmetal will try to expand, but it won't be able to because the surrounding metal is at room temperature. Expansion will concentrate in the stretched thinned area. If it is instantly
cooled at this point, the stretched surplus area will lock up. While the metal is hot, beat the perimeter of the
stretched area as if shifting the sheetmetal to the center. If the perimeter of the stretched area is large, repeat the
same action a number of times.
Shrinking should be done quickly. When heating, heat as small an area as possible to a high temperature. If it
takes too long and the heated area widens, the whole area will bulge and render the task meaningless. When
cooling, quickly cool the hot area while it is still hot. If it is cooled slowly, the sheetmetal that has collected in the
stretched area will widen and you will be back where you started.
n Principles of shrinking
À Suppose there is an iron rod whose ends are both blocked by walls
It becomes
red and soften
Á When the center of the rod is heated, the heated area will soften and the entire area will
bulge and try to lengthen.
 Because both ends can't lengthen as they are blocked by the walls, the swollen part will shift
to the area in the center that has softened
à If the metal is cooled rapidly while in state Â, the iron rod will try to return to its original
length. However, the total length will shorten because the area in the middle will have
cooled and locked up.
External panel repair 5 - 23
(4) Order of tasks
1) Heat shrinking using a welder
It is usual to carry out heat shrinking using the shrinking function of a spot welder or stud welder.
If the stretched area is not large, turn on the welder while pushing the shrinking electrode rather hard against the
center. When you take it away cool it straightaway with an air duster gun.
If the stretched area is large, begin at the perimeter of the stretched area and move toward the center in a spiral
motion.
n Heat shrinking using a welder
2) Shrinking using an oxy-acetylene welder
Gas welding was the main method used for shrinking before heat
shrinking became common. However, this requires a lot of practice.
Gas welding
torch
With the gas flame, heat the center of the stretched area so that a spot
around with a diameter of around 10 mm heats to a red color. Next, us-
Approx.
10 mm
ing a hammer and dolly beat the sheetmetal so as to shift it from the perimeter of the heated area towards the center. The secret is not to beat
too hard. Then immediately cool the heated area with a water-soaked
sponge or cloth. Hammer quickly, because if the metal cools while hammering it won't have any effect.
Using this method once will shrink an area with a diameter of approximately 10 cm. If the stretched area is large this has to be done a number
of times. In such cases, first shrink the center of the stretched area and
then the surrounding area.
Wet cloth
External panel repair 5 - 24
Sheet metal treatment 6 - 1
Chapter 6 Sheet metal treatment
Contents
1. Rustproofing ................................................................................................................................................... 2
(1) Causes of rust . .......................................................................................................................................... 2
(2) Rust prevention ......................................................................................................................................... 3
2. Surface preparation ....................................................................................................................................... 5
(1) Sandpaper ................................................................................................................................................. 5
(2) Substrate treatment procedure ............................................................................................................... 6
Sheet metal treatment 6 - 2
1. Rustproofing
(1) Causes of rust
As seen in the iron ore refining process, iron used to make sheetmetal exists in the natural world as ferric oxides
(FeO and Fe203). In other words, iron itself is an unstable element and exists joined to oxygen. This is why oxygen
is removed when making iron materials. Conversely, it means that iron combines easily with oxygen.
Oxidation is rusting, and oxygen which causes rusting is in the air (makes up around 21% of air. Most is nitrogen
(78%)). Oxygen is also in H20, or water, the cause of moisture, that is in the air. Rust is accelerated when salt (NaCl)
is added, and rust forms easily in coastal areas exposed to the sea and in regions where anti-freezes are used.
If iron is left it will combine with oxygen and rust. In the case of iron, rust will migrate from the surface to the
inside. This causes holes, reduces strength and makes iron brittle.
Painting is a means of preventing rust, and rustproofing is improved by applying a coat of sealer or an anticorrosion agent.
Air
Oxygen or moisture in the air condenses and adheres due to temperature difference.
Moisture
Rain, car washing
Rust occurs when chlorine is present.
Coastal regions and regions where anti-freeze is used.
Salt
Sulfur discharged from factories becomes sulfurous acid gas, and iron rusts even more
when exposed to this gas.
Acid rain also plays a part
Pollutants
When there is a huge change in air temperature, if iron comes into contact with a different
metal an electric current flows and the positive side rusts
Iron—Aluminum Õ Aluminum
Iron—Zinc Õ Zinc
Difference in electrical
potential
n Causes of rust
When moisture is attached to a sheetmetal, iron will seep
Water
H2O
Air
(Oxygen)
O2
O2
O
H
O
H
H
-
into the water as ion, combines with OH ion in water and
becomes ferrous hydroxide Fe(OH)2. If oxygen is further
bonded, it becomes ferric hydroxide = red ruster Fe(OH)3.
H
+
O
H
Fe
-
O Fe OH
Fe
+
Sheetmetal
Fe
+
OH
OH Fe
O2
OH
OH Fe
OH
OH
Fe(OH)3
Sheet metal treatment 6 - 3
(2) Rust prevention
1) Sealers
Sealers are mainly coated on joints to prevent water from getting in.
Check the body repair manual to identify the sites where sealer has been used, and if repairing a panel where
a sealer has been used make sure you seal the same site using a designated sealer or a repair product with the
same performance. Make sure you seal underframe parts.
Hood, door, and tailgate panels are already sealed.
n Examples of sites where sealers are used
I
H
P
J
E
O
K
N
L
A
B
M
C D
F
G
View A
View B
View I
View J
View C
View D
View K
View L
View E
View F
View M
View N
View G
View H
View O
View P
Sheet metal treatment 6 - 4
2) Anti-chip coatings
Sides sills and other sections are coated with an anti-chip coating to prevent rusting caused by peeling paint film
caused by flying stone chips. Sealers are thick and form a moderately uneven painting surface.
Since there are different kinds, check the model in the body repair manual and apply the same paint treatment
using a similar repair product.
3) Rustproofing wax
Rustproofing wax is applied to the inside of pouch-type underframe parts, hinges (hood, door, rear gate), and
some side sills.
Check the body repair manual to identify which sites have been coated in the body repair manual, and if repairing
a panel that has been given a coating of rustproofing wax, rustproof using the designated rustproofing wax or a
repair product with the same performance.
4) Undercoat
Undercoat is applied to underneath the body, suspension, etc.
Check the body repair manual to identify which sites have been coated, and if repairing a panel that has been
given an undercoat, apply an undercoat to maintain the designated thickness using the designated undercoat or
a repair product with the same performance. Mask around the sites to prevent the undercoat from adhering to
areas besides the designated sites.
Sheet metal treatment 6 - 5
2. Surface preparation
(1) Sandpaper
Sandpaper is used for surface preparation. This can be done using a sander or attaching sandpaper to hand sanding pads (holders, blocks). There is adhesive or Velcro on the underside.
Since the shape, size and positions of the suction holes for suctioning putty dust vary according to the type of
sander used, use sandpaper suitable for the conditions.
In addition to there being different kinds of paper for different materials and uses, there are different grits. The
lower the number the coarser the paper. Paper with a high number has a fine grit. Grades with a P comply with
the industry standard, so different makes of paper will be the same.
The basic rule when using sandpaper is to start with a coarse grit size and move gradually to a finer grit making
sure you do not a miss grit size in between. This is because you will have to get rid of marks left by the paper.
n Sandpaper grades
P16
24
Sanding metallic
surface
Rust removal
60
80
120
Rough sanding of
the metal sheet putty
180
Sanding polyputty
Plane grinding of
the metal sheet putty
Paint film
removal
* Differs according to colors or paint to be used
n Structure of sandpaper
Open
coat
240
Closed
coat
Sanding particles
Adhesive (two layers)
Backing
320
600
Sanding primer
surfacer
Sanding the old
paint film
1000
1500
Middle sanding
of the top coat
paint
Polishing
Sheet metal treatment 6 - 6
(2) Surface preparation procedure
1) Removing paint film
Paint film is removed when pulling panels in order to earth a tool or to
attach a washer.
When the repair has been made, remove paint film from other damaged
areas for surface preparation. Use a disc sander for this task.Use sandpaper with a grit size of P60 to P80.
Place the disc sander lightly against the painted surface, hold it at a 15 –
20˚ angle, and sand evenly. If you push too hard against the surface the
heat of friction will cause the sheetmetal to deform.
When repairing a small mark it is okay to use a double action sander
and start with a grit size of P120.
Since sanding will produce dust, wear a dust mask and safety glasses.
2) Feather-edging
Feather-edging is tapering the edge where the metal surface that appeared by removing the paint film and the paint film meet. Use a double
action sander and P80 to 120 sandpaper. Use a hard pad.
Surface preparation is an extremely important car repair process. If the
job is not done properly, sandpaper grains, leftover putty and blisters
will cause paint defects.
When feather-edging, taper off over a wide area. Hold the dual-action
sander gently, and sand applying the entire surface of the pad.
When finished, rustproof the surface by applying a metal surfacing
agent or a primer. Sanding the surface of rustproofed sheetmetal will
remove the zinc-plated layer, so this has to be done again.
Sheet metal treatment 6 - 7
3) Applying putty
À Handling putty
Stir the putty before using. Use a special stirring stick so that impurities
don't get mixed into the primary agent. For the hardening agent in a
n Stirring putty
Stir the putty sufficiently before using
tube, push down hard and mix it in with the cap firmly on.
Make sure you put the lid on the primary agent can so that dust and other impurities don't get inside. Commonly omitted from instructions on
the container is that there are putties for different temperatures (standard, summer and winter). Once you have opened the can use it up as
soon as possible. When it is cold, you can dip the can in 60 ˚C hot water
to soften it. Do not use an infrared drier.
The primary agent to hardening agent is based on weight, so measure
accurately using scales. If you have a good feel for the correct quantity
it is also okay to measure the quantities yourself.
Á Timing for applying putty
When repairing panels with tools, the extent to which a precise surface is achieved depends on the workshop's
quality policy and the skills of repairers. Applying putty when as clean surface as possible has been made will
shorten later processes. However, finishing a sheetmetal surface so that it is perfect requires much work and
a lot of time. The more you hammer or pull out a panel the more the panel will stretch. This will disrupt later
processes.
It is possible to use putty to repair dents that are up to 10 – 15 mm deep. There should be no stretching. Different
putties are used depending on the depth of the dent. Stretched areas should be fixed before this stage.
 Basics of applying putty
Different putties have varying limits for the depth to which they can be used. Ascertain the limit of the thickness of
the putty you are using. However, the thickness stated in the specifications is not achieved with a single application. It refers to the allowable final thickness after you have gradually built up the putty.
A single application will fill a depth of around 10 mm. Apply the putty in two steps if the dent is deep.
Keep the surface filled with putty as clean as possible. If there are obvious applicator marks, sanding will take
time and it will be more difficult to create a smooth surface. When the required amount has been applied, put the
spreader down and gently smooth the surface to get rid of the applicator marks.
Sheet metal treatment 6 - 8
à Preparation
Before applying putty, use a duster gun to blow away dust from the repair site and use a cloth containing a degreasing agent to remove dirt and oil. If putty is applied on top of dirt, sand dust or oil, there will be problems
when painting.
Putty or polyputty used after body repair is a two-pack base coat. Place only the required amount of the correctly
mixed filler and hardening agent on a mixing pallet and mix with an applicator. When you need a lot of putty, mix
and apply it more than once. Mixing a lot of putty at once will take time and the application will also take time.
Mix the putty evenly and quickly. The primary agent of the putty will start hardening rapidly as soon as the hardening agent has been mixed in. Mix the filler without letting air get inside. If air gets in it is possible that there
could be problems with painting later on.
Spread the hardening agent over the putty, rub it in and mix it by reversing directions until an even color is
formed.
n Degreasing
Wipe the site with a cloth containing a degreasing agent and then wipe with a clean cloth.
Sheet metal treatment 6 - 9
Ä Technique
Putty is applied in three steps: À folding; Á building up; and  smoothing. First, apply the putty with the applicator upright as if lightly folding. This will improve adhesion to the sheetmetal. Next, coat it holding the applicator
at a 30 – 45˚ angle. Apply a number of times as necessary for dents. Do not apply thickly in a single application.
Air could get in or holes could form. Lastly, clean and put aside the applicator, smooth the surface and get rid of
the applicator marks. Remove putty that has spilled over to the surrounding area.
The surfaces of panels to which putty is applied have a variety of contours. Use the most appropriate applicator
for the surface.
Choose a hard applicator for a flat surface. A soft applicator is suitable for slightly curved surfaces. For a steep
curve, the filler won't follow the crown unless an elastic applicator like a rubber applicator is used.
When applying filler to a curve, it tends to be thick on the edges and thinner in the center. If spread too thickly
sanding will take time. If spread too thinly filler will have to be applied again after sanding. Conversely, since
reverse crowns are hard to sand, apply a minimum amount.
For press lines, don't apply all at once. Check the shape and using the line as a border, apply putty twice, once
above the line and once below the line.
Attach masking tape next to the line on the upper side of the area being filled. When you have applied putty below, peel off the tape and apply putty to the top. If the putty is dry, you can also attach masking tape on the lower
side.
n How to apply putty
Folding
45 - 60°
ΠFirst apply the putty very thinly
and fold
Building up
30 - 45°
 Apply the putty repeatedly
as necessary
Smoothing
15 - 30°
Ž Finally lay down the applicator
and smooth the surface
n Technique for applying putty
Shapes of the damaged sections and
applicator handling
Applying putty at press lines
Tape
Tape
Putty
Removing the tape
Applicator handling a the tight curves
Rubber
applicator
You can apply the tape here
Putty
Body surface
Putty
Putty
Tape
Sheet metal treatment 6 - 10
Å Drying putty
Even when drying naturally, putty does not take much time to dry as at 20 ˚C it will dry in around 20 minutes. An
infrared-type drier can be used to fasten the drying process. However, care is needed as rapid heating and extreme temperatures can cause paint to crack or peel. Adjust the temperature by placing some distance between
the drier and the site.
If the temperature is 5 ˚C or below, drying will take longer. Not only heating up the body or the putty, but also
force dry instead.
Putty becomes hot when it is reacting. Thick areas will dry first because drying is hastened under reaction heat of
100 ˚C or more. Therefore, check how the paint is drying by scraping a fingernail across surrounding areas where
the putty is thin. This shows that sites with thin putty have poorer adhesion than sites in the middle.
Because high tension steel is not thick it is possible that shrinking or distortion can occur as a result of necking
when the putty dries. However, there are putties with less solvent and those in which another substance swells
to compensate for the solvent evaporation.
Sheet metal treatment 6 - 11
4) Sanding putty
Sanding putty consists of three steps: rough sanding, plane grind-
N Technique for putty sanding
ing and scoring. When applying the same putty or polyputty, scuff
Sanding flat surfaces
after the putty has been smoothed. Plane grinding is the hardest
technique, and ultimately is the domain of a paint technician.
Rough sand with a sander and do the last of the plane grinding by
hand to produce a smooth surface.
A double action sander, orbital sander, or straight sander can be
used for this. There are different sizes and different models for
different skill levels. Use a double action sander or orbital sander
Move the sander to all the directions
of the putty surface
Sanding tight curves
with a high number of oribt diameter. A sander with a large eccentric shaft has excellent sanding power.
The sander is moved differently depending on the work site and
shape. For flat surfaces, don't move the sander in the same direction, but move it back and forth, right to left etc at various angles.
Use P120 – 180 paper.
For a slightly curved surface, move the sander in a straight line
Move the sander
as if wrapping
the peak of the curve
Sanding gentle curves
at an angle to the vertical direction of the body. A straight sander
and long orbital sander are suitable for this. In the case of a long
thin repair surface, it is best to work in a lengthwise direction
when applying putty and sanding.
Press lines are treated the same as when applying putty. Use
masking tape to protect one side of the line while sanding the
other. Sanding the surfaces on both sides of the line will naturally
Move the sander to a constant direction
at an angle
Sanding press lines
Press line
produce the press line.
This method can also be applied to gently curved surfaces. Surface finishing can be done quickly by dividing the top and bottom
in two, sanding each part and lastly smoothing the middle.
When sanding, consider it as completely different
surfaces that are separated by the line
Sheet metal treatment 6 - 12
5) Checking the finish
For panels like outer panels of the doors and rear quarters where the vertical direction is curved but the front-back
direction is nearly flat, check surface finishing using a straight-edge. Use a straight-edge which is long enough to
straddle the filled area, put the ends on the unaffected surface and move the straight-edge up and down. If the
gap between the straight-edge and the filled surface is regular, the surface is almost smoothed.
If a guide coat has been applied to the surface of the putty beforehand, the remaining black spots will reveal the
high spots and low spots.
Although it is common for panel beaters to do the repair up to around the sanding stage, if a further surface finishing stage is required, use this sort of guide coat and do the final finishing by hand with fine grit paper.
n Guide coat
Damage analysis 7 - 1
Chapter 7 Damage analysis
Contents
1. Damage diagnosis . ........................................................................................................................................ 2
(1) Circumstances of accident ....................................................................................................................... 2
(2) Order of diagnosis .................................................................................................................................... 2
(3) Checking measurements .......................................................................................................................... 3
2. Underframe construction and damage ........................................................................................................ 3
(1) Damage prone places ............................................................................................................................... 3
(2) Easily overlooked damage ....................................................................................................................... 4
(3) Arrangement of opening parts and body damage ................................................................................. 4
(4) Front-end collision and damage .............................................................................................................. 5
(5) Side collision and damage ....................................................................................................................... 5
(6) Back-end collision and damage ............................................................................................................... 5
(7) Damage caused by secondary impact .................................................................................................... 5
3. Damage to outer panels ................................................................................................................................ 6
Damage analysis 7 - 2
1. Damage diagnosis
(1) Circumstances of accident
Check information concerning the circumstances surrounding the accident.
The "5 W" and "1 H" approach is the best.
• When: Time the accident occurred
• Where: Site and road conditions
• Who: Driver, passengers
• What: Another car or object
• Why: Cause of the accident
• How: situation at the time of the accident, speed (relative speed), load, impact site, angle, etc
(2) Order of diagnosis
First, check the damage in a light area where there is a hoist, jack, lamp, measuring tape, etc
Start with the whole vehicle and then look at individual sites.
• Overall appearance: Walk around the vehicle. Look for entry sites and around the damage. If there is
more than one site, check the order of entry and whether there is any pre-existing damage. Check to
see whether it conforms with the information you have received and whether there are other sites that
haven't been spotted.
Look for not only areas where damage has been caused by direct contact, but also secondary damage
and inertial damage caused by passengers or luggage.
• Damage sites: From the appearance of the damage sites deduce whether the damage is restricted to the
outer panels or whether it involves inner panels and the underframe.
Stand a certain distance away from the vehicle, and consider the site where the force of the impact hit
the vehicle, the directions in which it spread and the strength.
It's not possible to make effective repairs if you don't have a firm grasp of the location and extent of the
damage.
n Checking the damage
Walk around and check
Crash safety body
Impact
Sturdy
energy
cabinet
absorption
section
Impact
energy
absorption
section
In frontal collision, even
if the cabinet is intact,
the rear side may be
damaged
Damage analysis 7 - 3
(3) Checking measurements
When checking the extent of damage make a visual check and use measurements.
Damage to the underbody can be identified by taking measurements using a jig or centering gauge. For the upper body, measurements alone can sometimes not be enough. Because a visual check is not precise, you should
finally determine the dimensions of each site using a tram gauge or measuring tape.
N Visual check
N Checking by measurement
755
756
2. Underframe construction and damage
(1) Damage prone places
Because body strength varies depending on
the area and impact absorption construction is
used in some places, each part of a vehicle has
spots that are prone to damage. If you check
Sections where panels
have been joined
these spots you will get an idea of how far the
force of the accident has traveled.
Damage prone areas are areas where stress
Change in shapes
concentrates. They include around punch holes,
corners, places where the thickness of a member or reinforcement changes, and where panels have been joined.
Creases
Surrounding area
of the holes and space
Change in shapes
Corner
section
Damage analysis 7 - 4
(2) Easily overlooked damage
Huge bends and dents are easily seen. However, if there is not much deformation it can sometimes be difficult
to spot it with a visual check. For this reason, it's only natural that you check by taking measurements. There are
some points to look out for when making a visual check.
For example, when a frame (member) is bent, it can be hard to tell from the outer side of the direction of the
bend. In such cases, if you check the inner side too you will be able to tell from the creases. Conversely, even if
something does not look to be bent, if there are creases on the surface it will be bent and the side with the creasing is the inner side.
If deformation to the side frame, for example, is small compared with the overall damage, check to see whether
the side frame has gone into the toeboard.
(3) Arrangement of opening parts and body damage
You can tell deformation from the gaps
N Distortions between the gaps of the panels and the body
between the doors, hood and adjacent
panels. If the gap on the front side of the
front door is narrower even if the gap on
the other side is normal, it means that
Small gap
Correct gap
Small gap
Small gap
Damage up to
the front pillar
the damage didn't go further than the
front pillar. If the gap at the rear side is
also narrower, it is highly likely that deformation has occurred in the roof and
side sills.
If you look at the gap between the front
Damage beyond
the front pillar
fender and the hood, you can detect deflection in the front body. For example, if
the right of the front end is narrow and
bent toward the right. If the right of the
hood is high and the left is low, it means
Fender
Small
gap
Fender is
high
Fender is low
Hood
the right side has been raised.
Large
gap
Front is bent towards left
Hood
Fender
the left is wide it means that the body is
Right side has been raised
at the front
Damage analysis 7 - 5
(4) Front-end collision and damage
Damage to the front of vehicles is the most common.
When impact is light, it first pushes the bumper and deforms the front side member via the bumper stay. Depending on the impact site, deformation can also occur in the front grille, front fender, radiator panel and hood.
When impact is heavy, the whole of the front fender will be pushed in, the gap between it and the door will become smaller and the hood will get stuck on the front panel. The side member will bend near where it is attached
to the suspension members, and if there is a lot of deformation even the toeboard near the site where the member is attached will deform. If force travels as far as the front pillar, the back-end of the door will sag.There will
also be more damage to the wheel apron.
(5) Side collision and damage
The type of deformation varies depending on the shape of the body and the area where the force was loaded.
When there is a huge impact not only the doors and pillars, but also the floor and roof will deform. Because force
is loaded in the direction in which the entire side compresses, the wheel base may be shortened and it may affect
the front fender and rear quarter. The floor is prone to deformation on the inner side of the site where the side sill
is attached and where the center tunnel rises up.
(6) Back-end collision and damage
If the impact force is minor, damage will be limited to the rear bumper and around the rear skirt. However, if impact is greater, deformation will occur in the rear floor pan, rear side members and roof. In the case of the quarter
panel, if impact is minor, the fender area will bulge, and if impact is major the area up to the rear door will be
bent. An impact absorption structure is mainly used on the corner of the rear side members. In front-wheel drive
vehicles, particularly those with a rear gate, the simple body structure around the back end means that there will
be greater deformation for the amount of impact force. In some cases, deformation will extend to the center area
and the center pillars.
(7) Damage caused by secondary impact
Even in the absence of direct force, movement
by the passengers, luggage, engine etc caused
by an impact can cause damage. This is called
secondary damage. For example, the movement
of luggage in the trunk can cause damage.
The radiator, engine and transmission mounts
and base of the gearshift can be deformed by
engine movement. If impact is major, the inertia
force of the vehicle may cause damage to comparatively hard parts. This occurs in the roof and
side sills.
N Damages caused by luggage and other
Steering
Windshield
Toeboard
Trunk room
Damage analysis 7 - 6
3. Damage to outer panels
Because damage to outer panels appears in the form of dents, buckles, scratched paint film etc, it can be diagnosed by a visual check and by feeling with the hand.
There are two types of damage to outer panels. There is plastic deformation where they have received direct impact, and there is elastic deformation which occurs indirectly in the surrounding area.
Determining the area of the damage and the type of deformation can affect repair efficiency and time. The reason
is that by first repairing directly damaged parts where plastic deformation has occurred the elastic deformation
in indirectly damaged areas will largely be corrected. This means that restoration will take longer if you repair
parts with indirect damage first.
Removal and fitting of parts 8 - 1
Chapter 8 Removal and fitting of parts
Contents
1. Hand tools . ..................................................................................................................................................... 2
(1) Types of hand tools ................................................................................................................................... 2
(2) Twisting ...................................................................................................................................................... 2
(3) Gripping ..................................................................................................................................................... 3
(4) Cutting . ...................................................................................................................................................... 3
(5) Special uses . ............................................................................................................................................. 3
(6) How to handle hand tools ........................................................................................................................ 4
2. Power tools . ................................................................................................................................................... 4
(1) Removal and fitting tools ......................................................................................................................... 4
(2) Drilling and joggling tools . ...................................................................................................................... 5
(3) Cutting equipment .................................................................................................................................... 5
3. Removal and fitting pointers ........................................................................................................................ 6
(1) Tires and wheels . ...................................................................................................................................... 6
(2) Windshield glass ....................................................................................................................................... 6
4. Electrical components, wire harness ........................................................................................................... 9
5. Air bags ......................................................................................................................................................... 10
6. Types of oil .................................................................................................................................................... 11
Removal and fitting of parts 8 - 2
1. Hand tools
A variety of tools are used in vehicle repair. Below is an explanation of general-purpose tools, such as those used
for disassembly, assembly and cutting.
(1) Types of hand tools
Hand tools are tools that don't use electricity or compressed air and for which human strength is used. The functions of tools are mostly based on human hand movement. They can be divided into three categories according
to their function. Namely, there are tools that À twist; Á grip; and  cut.
(2) Twisting
1) Spanners and wrenches
These are mainly used to tighten or loosen bolts and nuts. They are used frequently. There are spanners that are
used to clamp the head of a bolt in a U-shaped opening part, ring spanners that are used by applying force to the
whole area surrounding a bolt, and a wheel brace type wrench that covers the head of a bolt. A socket wrench is
the same but it doesn't have the shaft a wheel brace type wrench has to cover a bolt. They come with attachments
such as different size sockets, handles with a ratcheting mechanism, and hand-held shafts.
2) Screwdrivers
Screwdrivers are used for tightening and loosening screws. They have slotted (-) and crosshead (+), or Phillips,
heads, and are also classified according to the type of handle they have. These include standard, stubby and
feed-through handles.
n Hand tools
Spanner
Crescent wrench
Wheel brace
type wrench
Socket wrench
Closed wrench
Screwdrivers
and others
Removal and fitting of parts 8 - 3
(3) Gripping
1) Pliers
In addition to ordinary pliers used for bending and cutting wire and iron sheets, there are needle-nose pliers
with a thin tip, circlip pliers, and linesman pliers that are handy for removing the coating of plastic wire and for
attaching connectors.
(4) Cutting
1) Saws
In vehicle repair, a hand saw is used for cutting pillars. Although hand saws are being used less due to the increase in the use of air-powered cutting tools in recent years, a hand saw is useful when more delicate work is
required.
2) Chisels
Rather than being used for cutting, in vehicle repair a chisel is used to remove spot welds on welded panels and
for hammering out press lines.
3) Cutters
Although there are cutters used for cutting metal that have crosscut blades and straight blades, today they are
hardly ever used in vehicle repair.
(5) Dedicated tools
These tools are not general-purpose tools. They are used only in vehicle repair.
1) Clip removal tools
These come in a variety of shapes. There are those like a screwdriver with a flattened Y-shape tip.
2) Welding clamps
These are usually known by product name, but are also called vice grips. They are used to hold panels to be
welded. There are various sets with a range of sizes and different shaped heads to suit different repair sites.
Removal and fitting of parts 8 - 4
(6) How to handle hand tools
The basic principle of hand tools is to know what they are used for and not to use them for any other purpose. For
example, you should not use a screwdriver to make a hole in sheetmetal or hit the head of a bolt with a spanner
just to speed up the job.
The lengths of spanners and wrenches and the thickness of screwdriver shafts are designed to provide the appropriate amount of force for the various bolts and nuts. Consequently, if they are lengthened using a pipe or
other tools or too much pressure is applied, not only the tool but also the bolt or nut you are working on could
be damaged.
n How to handle hand tools
Correct way to use
n Bolt and nut width across flat
Wrong way to use
Width across
flat
Bolt
diameter
Width
across
flat
Set deep with the size
matching to the bolt
Size of the width
across flat (14 mm)
Set horizontally
to the bolt
Size
indication
Size of the width
across flat (23 mm)
Strong force should be
applied to the pulling
direction
2. Power tools
Power tools driven by air or electricity are useful for reducing the amount of energy needed and are used to obtain a tidy finish.
(1) Removal and fitting tools
1) Impact wrench
An impact wrench tightens and fastens bolts while applying an impact
blow. It uses a hexagonal chuck. The shank, where the bits are attached,
comes in several sizes. The most commonly used sizes are half-inch (12.7
mm) shanks used for wheel nut wrenches and the 3/8-inch (9.5 mm) shank
used for removing and fitting panels and parts.
2) Air ratchet
An air ratchet is used to quickly turn bolts in narrow places. It can be used
with a socket wrench and bit.
Removal and fitting of parts 8 - 5
(2) Drilling and joggling tools
1) Air drill
An air drill is mainly used to grind down welds.
There are also drills designed for spot welds
that have adjustable depths.
2) Spot cutter
A spot cutter is used specifically for drilling a
hole in spot welds without wearing the tip. The
cutter is attached to a spot drill.
3) Punching tools
Punching tools are used for drilling holes in
MIG plug welds. There are also manual punching tools.
4) Flanging tools
A flange tool is used to make a butt on a joint
in a welded panel. Some types can also punch
holes while some come with different shaped
tips used for crowns and corners.
(3) Cutting equipment
1) Plasma cutter
Using a plasma arc and air, the plasma cutter
cuts even thick panels made of any type of material. It produces a clean finish on the cutting
surface.
2) Air saw
This is an air-powered saw. The saw blade
moves up and down, and there are low-speed
and high-speed models.
The air chisel was the first air-powered cutting
tool and was followed by rotary cutters and air
nibblers. The most commonly used tool today
is the air saw, which creates a clean cut.
Removal and fitting of parts 8 - 6
3. Removal and fitting pointers
(1) Tires and wheels
When removing and fitting parts, refer to the service manual and body repair manual. Below is a guide to points
requiring attention for various sites.
First, tires and wheels are often removed and fitted when repairing a vehicle.
Ride comfort and safety are impaired as a result of vibration caused by imbalance in tires and wheels due to
some spots being heavy or light. A wheel has both static balance and dynamic balance. Special equipment
(wheel balancer) is used to measure position and weight. A small weight is attached to the edge of the wheel to
regulate balance, but if it comes off as a result of impact caused by a collision the wheel's balance will naturally
be affected. Check carefully when removing or fitting tires or wheels and if it has come off the tire and wheel assembly will need to be balanced.
Because the wheel alignment is not the same for each wheel, once you have removed a wheel make sure you
return it to the same place. To do this, when removing wheels mark them to show their location, for example,
right front or left rear.
Checking tire pressure is one item to be checked before returning a vehicle to the owner.
When attaching or removing wheels and tires, check the torque and make sure they are not secured too tightly.
(2) Windshield glass
N Direct bonding method
Body flange
1) Attachment
Mole
Gla
is also used to retain vehicle strength.
Ad
ss
hes
ive
The attachment of windshields and rear windows not only seals a cabinet but it
The windshield is attached using either adhesive or weather stripping.
Dam
À Adhesive method
Glass attached using adhesive is attached by either direct bonding or flash
N Flash mount method
Body flange
mounts. The glass is attached to the body using adhesive for both methods, and
compared with the weather stripping method, but makes attachment/removal
and replacement more difficult.
sive
Adh
e
is buried in the adhesive. The adhesive method gives a vehicle more rigidity
Mole
Gla
ss
in direct bonding the mole is attached using clips and in flash mounting the mole
Dam
Ceramic coat
Á Weather stripping
This is also known as the gasket method. The glass is fixed in place using Hshaped weather stripping and a non-drying sealant is filled in the space between
N Weather stripping
method
Body flange
the glass and body.
Adhesive
Gla
ss
Mole
Weather stripping
Removal and fitting of parts 8 - 7
2) Removal and fitting
À Removal
For windshields attached using adhesive, remove using either a
N Removing with a knife
glass knife or piano wire.
(1)
Hold the knife with the blade and glass at a right angle and cut out
the adhesive sliding the blade along the glass. Start where the gap
(1)
between the glass and body is the biggest and be sure not to twist
the knife. Locating pins are attached to the corners of the glass so
(1)
remove these using piano wire.
When using piano wire, make a hole in the adhesive using a drill
or cutter, put the piano wire through and attach both ends to a
A-A
(2)
short piece of wood. Pull on both ends of the piano wire and cut
A
away the adhesive.
N Removing with a knife
Do not cross the wire and do not pull hard against the edge of the
(1) to damage nearby parts.
glass. Be careful not
(3)
(3)
(1)
(1) Cutter
(2) Protection tape
(3) Locating pin
(4) Knife for windshield glass
(1)
A-A
N Removing using the piano wire
(2)
A
(3)
(3)
A
A
(1) Cutter
(2) Protection tape
(3) Locating pin
(4) Knife for windshield glass
(4)
(4)
Removal and fitting of parts 8 - 8
Á Fitting
Remove dirt from the surrounding area and using a cutter
N Cut back the adhesive
knife cut back the adhesive on the body to create a smooth
(1)
surface around 2 mm (0.08 inch) thick. Be careful not to mark
(3)
the body or painting surface.
Next, align the positions of the locating pins on the glass side
and the holes on the body side and place the glass against the
body. Adjust the position, and after clearance at each of the
four corners has been evened, remove the glass and fit the
rubber dam.
Align the molding mark with both upper edges of the glass
(2)
(4)
(1) Adhesive
(2) 2 mm (0.08 in)
(3) Rubber dam
(4) Glass
and fit the molding from the upper corners to the center.
Attach molding double-sided tape evenly to the side of the
glass.
N Applying the primer
(1)
Using a sponge, coat primer on the adhesive surface on the
glass side and body side. At this point, because primer that
gets onto the body painting surface or the interior trim is hard
to remove, cover the surrounding area. Let the primer dry for
around 10 minutes. Do not touch the primed surface.
Apply adhesive to the edges of the glass, then using a rubber
suction cup insert the rocket pins on the body side and attach
the glass. Push lightly and make sure it is fixed in place. Even
(2)
(3)
(1) Application surface of the primer
(2) Glass side
(3) Body side
N Applying adhesive
out any excess adhesive with an applicator.
(2)
When installation is completed, leave the vehicle for about 24
hours.
(1)
Follow the adhesive manufacturer's guidelines for the minimum drying time and the length of time the vehicle should
be left before it is driven. Once the adhesive has dried, pour
water over the outside surface to check whether there are any
leaks.
(1) 9 - 12 mm (0.35 - 0.47 in)
(2) 8 mm (0.31 in)
When returning the vehicle to the owner, tell the owner not to
subject the vehicle to any hard knocks for at least three days.
N Clip the locating pin and
attach the glass
Removal and fitting of parts 8 - 9
4. Electrical components, wire harness
Vehicles are fitted with many electrically operated parts. They are covered with elaborate systems of wiring (wire harness) used to supply electricity and to control the
parts.
When attaching/removing electrical parts, make sure you take off the negative terminal on the battery beforehand. If removing parts with a memory function like the
audio unit and control unit, record the memory contents before taking off the negative terminal. If you neglect to do this all contents in the memory will be erased.
When attaching/removing and replacing panels and parts during vehicle repair, wiring often has to be disconnected. It is for this reason that connectors are fitted to
sites with wiring to enable disconnection.
Most connectors are made of plastic, so handle them with care as they can be damaged if handled too roughly. To ensure smooth re-connection, when disconnecting
wire attach a sticker or label so that you can identify where it is from.
N Connector
Removal and fitting of parts 8 - 10
5. Air bags
Air bags are adopted to improve passenger and driver safety. They are designed so that they will deploy upon
detecting impact. Since pyrotechnic devices are used to inflate air bags, they must be handled carefully.
The driver's air bag is stored in the steering wheel pad and the front passenger air bag is stored in the dashboard.
If there is damage or deformation occurs in the sensors, air bag module, air bag control unit, pretensioner, and
harness replace with a new product. Use a digital circuit tester when checking air bags. Do not use an analog
circuit tester, as the small amount of current inside could deploy an air bag.
Disconnect the air bag connector or remove the battery since an air bag may deploy unexpectedly.
Removing and installing air bags must be done with the utmost care. Refer to the service manual when doing this
and also if they are to be discarded.
n Follow the manual when working on air bags
Removal and fitting of parts 8 - 11
6. Types of grease
The radiator and air conditioning unit fitted at the front of the engine bay are often involved when repairing a vehicle. These parts
have to be removed when they are damaged and also when the
radiator panel is replaced. Always top up the radiator, but if the
level of water drops due to radiator damage, it must be filled with
water and the prescribed ratio of coolant.
Recover and fill air conditioner gas using special equipment.Dispose of the gas following recycling regulations.
Other work will require the removal and filling of other solutions,
such as power steering fluid, brake fluid, engine oil, and transmission oil. Since these are all vital for vehicle safety, you must
follow the guidelines set out in the service manual.
N Filling the refrigerant
Removal and fitting of parts 8 - 12
Repair of the underframe 9 - 1
Chapter 9 Repair of the underframe
Contents
1. Order for inner panel and underframe repairs ........................................................................................... 2
2. Body adjustment and alignment equipment .............................................................................................. 3
(1) Development history ................................................................................................................................ 3
(2) Types and characteristics .......................................................................................................................... 3
3. Setting the body ............................................................................................................................................ 6
(1) The role of setting . .................................................................................................................................... 6
(2) Basic setting methods .............................................................................................................................. 7
(3) Ancillary setting ........................................................................................................................................ 8
4. Setting up repair equipment . ....................................................................................................................... 9
(1) Setting up floor-type equipment . ............................................................................................................ 9
(2) Setting up platform-type equipment ..................................................................................................... 10
(3) Setting up bench-type equipment ......................................................................................................... 10
(4) Anchoring the damaged vehicle horizontally ....................................................................................... 11
5. Measuring the body . ................................................................................................................................... 11
(1) The purpose of measuring ..................................................................................................................... 11
(2) Types of measuring devices and characteristics . ................................................................................. 12
(3) Looking at body diagrams ..................................................................................................................... 15
6. Body alignment . .......................................................................................................................................... 16
(1) Accident entry and pulling ..................................................................................................................... 16
(2) Types of pulling equipment and characteristics ................................................................................... 17
(3) Three elements of force .......................................................................................................................... 18
(4) Clamping ................................................................................................................................................. 21
(5) Pointers .................................................................................................................................................... 24
Repair of the underframe 9 - 2
1. Order for inner panel and underframe repairs
Body
adjustment
and
alignment
equip-
ment is used when repairing damage to the
Work
procedure
Summary
underframe.
The basic order when using this equipment is
to fix (set), measure, repair, measure, replace
welded parts, and unfasten (reset).
Anchoring the
vehicle on the
repair equipment
4-point anchoring
Procedure of the repair equipment
to be used
Safety measures
Measurement
Utilizing measurement devices
included in the repair equipment
and various measuring devices
Repair
Adjusting the positions, angles and
forces of pulling and pushing
Utilizing various clamps
Safety measures
Repeating
measurement
and repair
Dimensional drawing of the body
Utilizing measuring devices
Final
measurement
Utilizing measurement devices
included in the repair equipment
and various measuring devices
Replacing
welded parts
Utilizing the body manual
Optimal use of various welding
equipment and tools
Safety measures
Remove
fastenings
Procedures of using repair equipment
Safety measures
The work returns the vehicle to its original dimensions. By repeated repairs and measurements, the original dimensions of the frame are
gradually restored. Leave structural parts that
are scheduled to be replaced on until you have
obtained the measurements you need.
When the dimensions are correct, unfasten the
vehicle from the adjustment and alignment
equipment after the welded panels have been
replaced.
Repair of the underframe 9 - 3
2. Body adjustment and alignment equipment
(1) Development history
Repairing a vehicle body deformed in an accident most likely started at the same time as the invention of the
automobile. In those days, repairers inherited repair techniques used for horse-pulled carriages. For a long time,
basic body construction remained virtually the same as that used for carriages, except that wood had been replaced by iron.
Huge changes appeared in body construction with the birth of the unitized body. There was a significant increase
in vehicles with the unitized body in Europe after the Second World War. That was when special repair tools for
this type of body and present-day body adjustment and alignment equipment appeared. Little was written about
this so details remain unclear.
We do know, however, that the forerunner of today's jig type equipment was developed in France in the 1950s. It
is thought that the owner of a car repair workshop developed it by making modifications in the course of carrying
out daily repair work.
The floor-type Blackhawk Korek system was introduced to Japan from the United States in the early 1970s. Meanwhile, domestically produced floor-type auto poles appeared one after the other. This type of equipment most
likely became widely adopted due to demand for more efficient repairs accompanying the sudden rise in vehicle
ownership.
This was followed by an increase in equipment imported from Europe and elsewhere, as well as the development
of improved models in Japan. By the 1980s they had been introduced to a great many vehicle repair workshops.
This is also when there was an increase in equipment that was solely used for anchoring vehicles, as well as a
variety of related equipment such as measuring equipment.
Today, most main types of overseas equipment are imported to Japan, and along with domestically made equipment both are used taking advantage of the benefits particular to each system.
(2) Types and characteristics
1) Criteria for body adjustment and alignment equipment
Equipment must use huge force to pull the deformed underframe while the vehicle is braced so that it won't
move, and must be able to measure deviation from standard positions with millimeter accuracy. This equipment
serves three main purposes.
Although some have a single function, the systems were originally designed to have these three functions.
There are three main different types of system: floor, bench and platform (drive-on).
À Pulling equipment
This is used to pull and push parts of the body freely with a specified force.
Á Anchoring equipment
This stops the body from moving from its position when force is applied. What is more, vehicles can be anchored
and released quickly.
 Measuring equipment
This equipment gives accurate measurements and comparisons without needing plenty of experience.
Repair of the underframe 9 - 4
n Three requirements
Fastening
device
Pulling
device
Fastening
device
Measurement
device
This will set the vehicle firmly
as the applied force is effectively
utilized
ΠSetting the vehicle
 Resetting the vehicle
Measurement Checking distortions of the sizes and  Checking the degree
device
of deformation
conditions of the reconstruction
Pulling
device
This device generates effective
force by using the power such
as hydraulic device
Ž Roughing out
2) Floor systems
Floor systems anchor pulling equipment and anchoring equipment to rails or anchors embedded in the floor.
They allow independent use of individual systems and allow
the easy anchoring of single sections. They don't take up much
space, as when not use the various parts can be stored away.
However, the rails or anchors remain in the floor.
Rails are made of aluminum as well as steel, and some systems
use a rubber cover to obtain a flat surface.
The individual parts can be used flexibly in combination with
other adjustment and alignment systems and equipment.
 Checking the degree
of reconstruction
(repeat pulling/measurement
and carry out the final check)
Repair of the underframe 9 - 5
3) Bench-type systems
These systems are based on taking measurements using a jig.
A jig is mainly used to show the correct positions of major points on the underbody. There are dedicated systems
that require special attachments for each vehicle model, and there are universal systems that can be used for any
model by relying on a frame chart. Many of these systems are European.
The platform used to set the jig is a jig bench, and pulling systems and setting systems are also set using the
bench. The bench itself is portable. However, for reasons of convenience the system is often used in combination
with a hoist, which means it occupies its own space. Lifts improve efficiency as the height of the vehicle can be
freely adjusted during the repair process.
Since all that is required is to pull in the direction of the dimensions and positions showed three-dimensionally by
the jig, work is fast and even the inexperienced can use this system. However, it does take time to set up the jig.
Portable bench and bench placed on a hoist.
4) Platform system
This is also known as a drive-on system because the vehicle is driven on to the work platform.
The pulling system and anchoring system are integrated, and setting up requires a certain amount of space.
Many of these systems are made in North America.
To set up, the platform is tilted so that the end is at floor height, and the vehicle is driven or pulled by a chain onto
the platform. Because the vehicle is around one meter off the ground it makes working on the suspension easy.
Platform tilts and moves up and down
5) Other systems
Other systems are basically variations of the floor, jig bench and platform systems.
Some platform systems have a scaffold (birdcage) that encloses the entire vehicle. These systems enable pulling
from many directions.
Some systems combine a jig bench with a platform or floor system.
Simple floor systems with only anchoring parts can be used in combination with separate measuring and pulling
systems. The advantage of this system is the low initial cost.
Repair of the underframe 9 - 6
6) Related equipment
In addition to the functions of anchoring, measuring and pulling, body adjustment and alignment systems come
with a variety of other related devices and equipment
Clamps are used to grip panels, and there is a wide variety of shapes owing to the variety of damage sites and
conditions. There are underbody clamps (generally used at the front and rear right and left sides of the side sills)
that anchor the body and panel clamps used on damaged sites and for additional anchoring.
Hydraulic rams have been mentioned earlier in the section on repairing outer panels. A hydraulic ram is a must
because it can be used universally, from a tower used for making repairs through to a power unit that pulls chains
and a tool that does auxiliary pushing and pulling using attachments.
There are also chain pullers (chain blocks) that can be used to pull. These are used when pulling systems are too
strong and when repairing minor damage. They can also be used for auxiliary anchoring.
Measuring systems are part of body use of attachments systems and are mainly used on the underbody. There is
also the tram gauge, which is used to measure lengths of certain parts.
More detail on various devices and instruments is included in a later chapter.
3. Anchoring the body
(1) The role of anchoring
Pulling force cannot be used effectively unless the vehicle body is firmly anchored.
The anchored parts receive the same force used in the pulling process. If a low strength area is anchored when
strong force is applied, the anchored part will either deform or disintegrate.
Even for strong areas the right site must be chosen, otherwise moment caused upon the application of force may
result in the application of force in a different direction. Not only will this slow down repair work, but it will cause
additional deformation.
n Role of anchoring
Adequate force cannot be applied without firm anchoring.
Repair of the underframe 9 - 7
(2) Basic anchoring methods
Basic anchoring is combined with setting up the body alignment system. Normally, the flanges under the side
sills are anchored to the equipment using underbody clamps or special clamps for particular car models. The
body is anchored in four sites, front back left and right.
The four clamps must be connected so that strong force is not applied to one site only. Though vehicle models
vary, because with the floor system the anchor sites are apart from one another the underbody clamps are connected with metal tubes shaped like a hanging rack. They are not connected in bench or platform systems because the anchored sites and the bench are close.
If there are no flanges under the side sills, create anchorage by welding on a thin panel or use a special anchor
adapter available for each model. In cases where the frame is separate, like for a truck, the frame and body are
anchored separately.
Anchoring is also difficult if there is damage to the side of the body. Anchor the undamaged side as normal and
add anchor points at the front and rear to disperse the pulling force.
n Basic anchoring
Side sill
Pulling
direction Set in a way that the direction
of the teeth on the underbody
clamps will face opposite to
the pulling direction.
Underbody
clamp
For the floor system, the four anchor sites
are connected in a double cross.
Repair of the underframe 9 - 8
(3) Supplementary anchoring
Depending on the direction of the pulling force,
adding supplementary anchoring can make repair
easier by making effective use of the pulling force.
Supplementary anchoring is mainly required in the
following instances.
1) To reinforce basic anchoring
When chains are used for anchoring, the direction
of the pulling force can cause the chains to slacken. In such instances, add anchors in the opposite
direction.
2) To counter moment
Not all pulling is done on the center of the body.
Adding anchors in the direction of the moment
caused by pulling and the opposite direction of the
moment will prevent further deformation.
3) To prevent excessive pulling
Pulling force travels to a fixed point and does not
affect any points past the fixed point. For example,
if you want to pull on the front half of the front
frame, anchors should be added immediately behind the area you want to align. Adding anchors
to the opposite side when pulling from the side
makes effective use of the force.
4) To protect opening parts
The upper part of the body is not anchored. Consequently, when strong force is applied it can have
an effect as far as the front pillars. Therefore, connecting the top of the front pillar and the upper surface of the side sill will prevent deformation in the
door. When pulling near the trunk, add a heavy rod
to the part where the trunk opens.
Repair of the underframe 9 - 9
4. Setting adjustment and alignment equipment
(1) Setting floor-type adjustment and alignment equipment
Assemble the anchoring system over the floor rails and anchors and set the damaged vehicle. Although this will
vary slightly from model to model, first move the vehicle to the prescribed position. If the vehicle cannot be driven, use a trailer or tow truck. If using manpower, use three or more people and designate one person to monitor
the surrounding area. If the steering wheel or brake can be used move the vehicle after checking them.
Place damaged parts in a wide corridor, transport the vehicle to the prescribed position of the rails and anchors
and first attach underbody clamps to the underneath of the side sills. Sites near the jack points listed in the service
manual are suitable locations for the clamps. Then install the piping that connects the front back and right and
left. Leave the anchor bolts in place.
Next, assemble the anchoring system in line with the underbody clamps and fix it to the rails. If you are able,
raise the vehicle using a jack or the hoist that comes with the adjustment and alignment equipment. When using
a jack, set up a rigid rack by jacking the front and back separately. A rigid rack can be omitted if work underneath
the body is not necessary.
Adjust the positions of the underbody clamps and the anchoring system, and when it is firmly in place tighten
the connecting pipes. The setting is now completed. For the fastening type that uses chains, support the body by
placing rigid racks against the right and left connecting pipes. Then anchor the vehicle by attaching at least four
chains to the front and back on both sides of the vehicle. If the vehicle is severely damaged, it is a good idea to
add chains in the pulling direction and in the opposite direction.
Œ

Attach underbody clamps to the four sites of
the side sill flanges
Lift the rear side using a jack and set
the anchor stand
Ž

Place the rear side on the anchor stand
and set the anchor stand in the same way
for the front side
Once both front and back are on the anchor stand,
join the connection pipes and fasten the vehicle
using chains, wedges and bolts
* If the hoist is installed at the center of the floor type repair equipment,
those operations  and Ž can be completed at once
Repair of the underframe 9 - 10
(2) Setting platform-type adjustment and alignment equipment
After moving the vehicle near the equipment, either tilt or lower the platform and either drive the car onto the
platform or use a winch.
Return the platform to its proper position, raise the vehicle on the platform using the jacks that are originally included and attach the underbody clamps and anchor stands. Take down the jacks and fix the anchors to the base.
Setting is now completed.
For vehicles with damaged tires that can't be driven, use a special support with wheels.
Œ

Place the damaged car on the tilted
platform by either driving the car or
using a winch
Ž
Set the fastening clamps and
fasten the car on the platform
Remove the wheels
(3) Setting bench-type adjustment and alignment equipment
The methods of setting up a bench-type system vary depending on whether there is a hoist and on the type of
hoist.
If there is no hoist, place the damaged vehicle on a support stand. After attaching the underbody clamps, put the
bench underneath the vehicle, raise the bench with a garage jack and attach the anchor stands to the bench. Raise
the bench higher and take down the vehicle stand.
If there is a forklift or similar type of hoist that can raise the vehicle from the side, a stand is not needed as the
vehicle can be placed directly on the bench. Raising the vehicle with a hoist with four or three columns makes
this task easy. Since the bench has casters, after setting up you can move it to a space where you can work on
the vehicle.
If the bench body is attached to a hoist, raise the vehicle once on the bench, support the vehicle with a special
stand and then attach the underbody clamps. Although you can't move it once it has been set up, the vehicle can
be raised and lowered while working.
Benches that serve as measuring systems can also be used in conjunction with floor-type and platform-type
equipment. In such cases, the vehicle is anchored to the bench, the vehicle to the adjustment and alignment
equipment and the equipment to the bench.
Œ

Raise the bench with a hoist
and lift the damaged car
Ž
Support the car with wheel stands
or a rigid rack that can be used
from the gaps of the bench, and
lower the bench
Set the underbody clamps and raise
the bench again and remove the stands
Repair of the underframe 9 - 11
(4) Anchoring the damaged vehicle horizontally
Different systems have various tricks to loading vehicles that make the work more efficient. It is important that
you grasp these various features.
For almost all models it is important that the damaged vehicle is positioned horizontally. To be accurate the axis
of the bench or platform should be parallel with the vehicle. With floor systems, the vehicle should be positioned
parallel to the baseline of the measuring system, or if the floor is level the vehicle should be anchored parallel to
the floor.
5. Measuring the body
(1) The purpose of measuring
The body is measured to determine how misaligned the various parts of the deformed body are.
1) Length
The simplest measurement is to compare the length. For example, if the left fender is shorter than the right front
fender, the left side has been pushed in.
However, this is not an accurate assessment. This is because it is possible that the right side has stretched.
2) Diagonal measurements
Another way to compare measurements is to compare the diagonal measurements. The diagonals of the symmetrical quadrangles are the same. A vehicle body has many symmetrical parts, and this makes it possible to
see deviation. Use a rod or something similar to measure the length of one of the diagonals and then use it to
measure the other diagonal. If the lengths are the same the vehicle is normal, but if the dimensions are not the
same there is deviation.
However, this only tells you the positional relationships of the four corners of the quadrangle and nothing about
the panels in the middle. Also, since the body is three-dimensional, deviation occurs not only at the right and left
of the front and back, but it also occurs above and below. Determining deviation based only on two-dimensional
diagonals has its limitations.
n Compare the opposing corners
Repair of the underframe 9 - 12
3) Numeric conversion
To grasp an accurate picture of the state of the vehicle lengths need to be substituted with numbers and interpreted. This is the task of measuring. Taking measurements will, for example, tell you that the upper surface of the
front fender is 800 mm on the right and 780 mm on the left. However, this information is not enough. You must
refer to the body manual to check the original dimensions. When you do this you find that the correct length is
805 mm. This tells you immediately that both lengths are wrong.
(2) Types of measuring devices and characteristics
The tram gauge and centering gauge are examples of universal measuring instruments.
1) Tram gauge
The length of the tram gauge is adjustable, and there is an indicator needle on the ends of each of the rods that
can also be secured. The rods have a measuring tape and weights, and gauges from which the figures of the
dimension between the two indicator needles can be read directly are most common. A tram gauge is useful for
measuring the distance between two points on the body and it is also easy to handle. It is indispensable in body
repair work.
This range is expandable
Measure tape
Indicator needle
Points the measured position
This range is expandable
Measure tape
Indicator needle
Points the measured position
Repair of the underframe 9 - 13
2) Centering gauge
When suspended at the symmetrical points of
the underbody it will automatically show the
body's center line. By looking through a pin
from one end you will see the deflection of the
body. It takes a little time to learn how to look
through the pin.
Other gauges that are suspended under the underbody include those that use a plate to measure the distance using laser beams. The center-
Deflection of the center is
checked through the pin
alignment
ing does not provide figures, it only allows you
to check alignment.
3) Adjustment and alignment equipment and measuring systems
Hooks to be attached
to the body
Although jigs are often used in systems that
combine measuring systems, there is a variety
of other systems that are also used.
These include measuring using laser beams,
and the use of computers to read data on the
positions of indicators set under the underbody
that can make real-time comparisons of these
measurements and the correct dimensions.
4) Jigs
A jig is a tool used for aligning parts. Jigs that
N Dedicated jig
are used in alignment systems show the normal
positions of major body sites and parts. There
are universal jigs and dedicated jigs
À Dedicated jig
A dedicated jig uses attachments designed for
a specific model. They can also be used to hold
the position of a new panel for placement and
welding.
Á Universal jig
A universal jig can be used for many models by
altering the way in which the provided jigs are
assembled. The jigs are assembled by following the directions according to the body charts
prepared for each model made by the manufacturer by taking actual measurements.
N Universal jig
Repair of the underframe 9 - 14
n Body charts
Each universal jig system has its own set of body charts.
Repair of the underframe 9 - 15
 The principle behind a measurement plane
A plane is made at a set distance parallel to the body. It is possible to show the correct positions on the body using positions on this plane and this distance between the plane and the various areas on the body. As a plane, it
doesn't have to be a plate-like surface with no gaps. A virtual plane is also acceptable. This is the basic principle
behind jig-type measuring systems. Apart from ordinary jigs, there are also systems that extend arms from the
frame to create a virtual plane and have attachments provided with measuring tapes.
Body dimension charts show the dimensions of a projected plane.
n Measurements using a virtual plane
Virtual plane for
measurement
Jigs, platform, floor surface, measuring device, etc
(3) How to read body charts
1) Body dimension charts
Body dimension charts show the true dimensions of new vehicles and are used for vehicle alignment. They are
included in body manuals for each model.
Because with a unitized body the engine and suspension are directly attached to the body, their layout has a
bearing on traveling performance and safety. For example, if the position of strut mounts is incorrect, the wheel
alignment will be out, the vehicle won't travel straight, and the tires will suffer from abnormal abrasion.
If you have a body dimension chart you can proceed with body repairs even if the new panels haven't arrived.
2) Linear distance measurements and plane projection measurements
In Subaru body manuals, the underbody is shown by plane projection measurements and the upper body is
shown using linear distance measurements.
À Linear distance measurements
Linear distance measurements are taken by measuring the direct distance between two measurement points
(vehicle reference points).
They are easy to understand because they can be measured directly using a calibrated tram gauge. However, it's
often not possible to measure the inside of the engine room if the engine is there.
Repair of the underframe 9 - 16
Á Plane projection measurements
Plane projection measurements are obtained by establishing a virtual plane parallel to the body, and take measurements from an image of the body projected onto the plane. In other words, it takes planar measurements that
do not take account of differences in height and width.
This is almost impossible to do with an ordinary tram gauge or measuring tape. These measurements are useful
when using a set body and alignment and measuring equipment that have a parallel measuring plane (or lines).
A cord with an attached weight is hung from the measurement points, and the distance between the places where
the weights come in contact with the measurement plane is measured. This is why some systems (and measurement systems) come with indicator needles. Using this method it is possible to get the required measurements
even if there are obstacles, such as the engine, suspension, and parts, in the way of taking a linear distance measurement between two points.
n Linear distance measurements and plane projection measurements
Even with the dimension between
the same measurement criteria
positions, its value may differ
according to measurement methods
Linear distance measurements
Plane projection measurements
Virtual
measurement
plane
In parallel with the central line of the body
3) Obtaining accurate measurements
Most of the body is symmetrical, but there are some areas that are asymmetrical. Although it is difficult to know
right from left in the underbody, basically these are described from the point of view of looking down on the
vehicle from above. Consequently, when taking measurements under a vehicle be aware that right and left are
reversed.
Figures will also be incorrect if linear distance measurements and plane projection measurements are confused.
When measuring the same place it is often shorter to take plane projection measurements rather than linear
distance measurements.
Since a vehicle's reference points are surprisingly hard to find, check using diagrams in the body manual. Measure from the center of a hole.
6. Body alignment
(1) Accident entry and pulling
It is often said that in order to repair a damaged body all you have to do is apply the same amount of force in the
opposite direction to the impact that occurred. In fact, however, it is difficult to accurately determine the amount
of force and direction. Even if it were possible, the momentary force of an accident and the slower task of pulling are not the same. Also, body panels damaged as a result of the impact may already have a different strength
compared with the original body as a result of work hardening.
Repair of the underframe 9 - 17
(2) Pulling systems and characteristics
1) Principles of hydraulic systems
Hydraulic systems are indispensable when repair-
N Pascal’s principle
ing a vehicle body.
Pascal's principle applies to hydraulics. Namely, if
10 kg f
there is a piston with a sectional area of 10 cm2, and
1 kgf (9.81 N) of force is applied to oil (fluid) inside a
100 cm²
10 cm
device, a separate piston with a sectional area of 100
cm2 connected by the same fluid will move with a
1 cm
1 kg f
10 cm²
force of 10 kgf (98.1b N). If the size ratio of the piston
on the input side and the piston on the output side
is altered, the same force can be increased infinitely.
However, the strokes will decrease correspondingly.
if 1 kg f (9.81 N) of force is applied using a piston with the
sectional area of 10 cm2, since the force will be applied equally to
the whole liquid, the piston with the sectional area of 10 times
bigger, 100 cm2 will have the force of 1kg f x 10. In other words,
the ratio between the force and sectional area is always the same
2) Hydraulic mechanism
In a simple hydraulic device used in body repair,
n Hydraulic units and work
the fluid to which pressure has been added by
manually pushing a pump amplifies its force in a
piston in a hydraulic ram. A hydraulic ram can be
used for a variety of purposes, centering on pistons, by fitting new pipes and changing the attachments on the tip.
Its many uses include widening a spot that has
been pushed in, raising an area that is sagging and
stretching a panel that is compressed. But because
of its force it is often used to repair sites on the
frame, such as frames (members) and pillars.
When a hydraulic ram is about to release a large
amount of force the stroke (ram) displacement decreases. As a result, there is a limit to how much
manual pumps can be used when the pushing dis-
n How to convert stretching force to pulling force
Chain
tance is long and you want to increase force.
An air pump driven by compressed air is used in
such cases. With the flick of a switch you can get
the required force and stroke.
Most hoists and jacks used for repairing vehicle
bodies are air-driven hydraulic rams and have basically the same structure as those used to repair
panels.
On its own a hydraulic ram can virtually only produce force in a pushing direction. However, by
combining a ram with chains it is possible to produce force in a pulling direction.
In reality, the pulling direction will not
change as shown in the diagram
Repair of the underframe 9 - 18
3) Chain puller
Not only hydraulic rams produce large pulling
force. Wire pullers and chain pullers are used
as tools that amplify human force in a pulling
direction. Both produce force by reeling wire
or chain. Although it is a person who reels the
wire or chain, a continuous large force can be
used because the reel has a lever that multiples the force.
4) Pulling systems
Damage that hasn't affected the underframe can be repaired using pulling systems that use chains, clamps, hydraulic rams, chain pullers, floor anchors and rails.
The extent to which a vehicle is firmly anchored varies according to the size of the force that is to be applied.
(3) Three elements of force
1) Magnitude and direction
Magnitude, direction and point of application are the three elements of force.
Arrows are often used to express the magnitude and direction of force. Magnitude is shown by the length of the
arrow and direction by the direction of the arrow. This type of representation is known as a vector.
When represented by a vector, it is easy to imagine the composition and dispersion of force. Composition can be
thought of as a single force made from two or more forces applied from other directions. Dispersion is the way
in which force applied from a certain direction spreads and transmits.
n Methods of expressing force
Dispersion of forces
Composition of forces
Added force
Magnitude of force
Direction
of force
Point of application
(Point where
force is applied)
You can indicate here
Dispersion of forces
Added force
Combined force
Repair of the underframe 9 - 19
2) Principle of action and counteraction
When force is applied to an object, the same
n Action and counter action
amount of force is produced in the opposite direction. For example, if a drum on the ground is
Action
Counter action
pushed with a force of 10N it will produce a counter
force of 10N in the drum in the opposite direction.
This force functions as a kicking force against the
ground by the person who is pushing the drum.
Therefore, when the ground where you kick is slippery like ice and thus the counter force is not able
to be transmitted to the ground, the drum won't
move at all no matter how hard it is pushed. The
initial pushing force is called action and the repellent force is called counteraction.
Rockets and jet planes fly in the sky because of the
Action
Counter action
force of the counteraction in the opposite direction
to the force injected by burning fuel.
When pulling force is applied in a pulling direction to a body that is anchored to an alignment system, the body
will produce a reaction force in a pushing direction toward the alignment system and the alignment system will
produce a similar reaction force in a pushing direction toward the floor or bench. Accordingly, force more than
that which can be sustained by the anchoring system cannot be applied to the body. Also, since force is also applied to the body where it is attached to the anchoring system, if that section is weak it will not be possible to
apply a large amount of force.
3) The action of inertia
When the same amount of force is applied, it acts differently depending on whether the force is applied slowly
or whether the same force is applied momentarily. For instance, if a certain amount of force is steadily applied to
a stationery vehicle, the vehicle will start moving in the direction to which the force has been applied. However,
if a huge force is applied momentarily, the area to which the force was applied will deform. This is how inertia
works.
In other words, inertia means that a body in motion tends to remain in motion and a body a rest tends to stay at
rest. Inertia is in proportion to the weight of the body.
Force received by a car in an accident is momentary force. Therefore, even though a vehicle that is not anchored,
it will not produce moving force and as a result the body will deform. In contrast, force applied when repairing is
applied slowly. Consequently, if the body is not firmly anchored the vehicle will move. The force will also have a
wider effect than the force did in the accident.
n Inertia
Heavier objects are more difficult to move, and once they move, you need larger force to stop them
Repair of the underframe 9 - 20
4) Concentration and dispersion of force
When force is applied at one site to a material made entirely of the same substance and which has a uniform
shape, the force will be transmitted throughout the entire material. If the force exceeds the strength of the material, it will deform or break, but where that will happen can't be known until it occurs. However, if the area or
shape of a material varies, for example it suddenly narrows or there is a site where it folds over, it will always
deform or break at those points. This is because the force is concentrated in these areas. This is called the concentration of stress.
n Concentration of force
The area where the force is
concentrated
When the whole area is even,
it depends on the way of applying
force for where to be bent
If there is an area where the force
is concentrated, it is always bent
from this section
Punched
hole
Change in
sectional area
Curve
(corner)
5) Moment of force
Objects have a center of gravity, which we can think of as the place where that object's weight concentrates. This
isn't always the place that appears to be its center.
Force applied to the center of gravity can be seen as applying force to the entire object. If the object is not anchored, it will move in the same direction as the applied force. However, if force is applied to a site away from its
center of gravity, the force will act as a rotational force centering on the center of gravity. This is moment.
The anchored parts of an anchored object will behave like that object's center of gravity. When force is applied to
an anchored body, force will be applied to unexpected directions if thought is not given to the anchored points
and the direction of the force.
Moment
Center of gravity
Center of gravity
Moment
Center of gravity
Center of gravity
If force is applied to a site away from its center of gravity,
moment will be generated and a rotational force is created
Repair of the underframe 9 - 21
(4) Clamps
1) Structure of clamps
Clamps are used so that force can be applied when
pulling the body. Although clamps are generally
tools used to hold something or to clasp something, clamps are used in alignment work as tools
that are attached to panels and to which force is
applied.
With the exception of special clamps, clamps used
for pulling have two rows of teeth that clip onto a
panel or flange. The teeth are pressed against the
Because of the wedges,
as the application of
the forces becomes
greater, so is the force
of biting into the panel
As you apply more forces,
the teeth will bite into
the panel
panel by tightening a bolt. If the pulling force is
correct, the more that force is applied the more
the teeth will take on a shape that sinks into the
body. The bigger the area of the teeth the greater
the amount of force that can be applied.
Although the part that clamps the body is similar
for every shape of clamp, the clamp itself comes
in various different shapes. This is so that they
can be attached anywhere on the body. There are
clamps that can be used universally in various different places and those that are for use in a special
single site. Clamps can be divided into the following broad categories.
À Universal clamps
These are attached to flanges or the end of panels.
They come in various shapes and sizes and can be
used for a wide range of sites.
Á Vice clamps
Because vice clamps have a large throat they can
be attached to the body over an obstacle. Vice
clamps are used in areas where universal clamps
cannot be used, such as an edge with a box structure, like the roof and floor, and for clamping a
pouch panel that uses service holes. They are also
known as C clamps because of their shape.
 Special clamps
These are clamps with shapes made to fit the body
and panels.They can be used only on specific sites.
They include blade clamps used for bolt holes in
struts and narrow clamps used on the roof rail.
For strut tower
For fastening the body
(floor type: a set of four)
Repair of the underframe 9 - 22
2) Clamps and pulling direction
Clamps are designed to be pulled front to back, up and down, and right to left. The pulling direction is determined
by the structure of the clamp. A clamp cannot be pulled in any direction.
The extended line of the pulling direction must pass through the center of the teeth. If this is not exact, moment
could cause the teeth to slip and the clamp to break.
This precaution applies to every type of clamp.
n Correct way of pulling clamps.
Moment
Moment
Pulling direction should be
matched to the center of the
area where the clamps are
biting into the body
If pulling off center,
the panel may be
scratched and being
disengaged easily
Repair of the underframe 9 - 23
3) How to handle clamps and chains
If clamps are handled badly they can't be used for long, work efficiency falls
and the risk of accident increases. Be mindful of the following points in the
daily use and maintenance of clamps.
À Check the clamp's teeth
A large amount of force is applied to the body via the teeth on a clamp. If the
teeth are in bad condition, the force will not be transmitted. Teeth have a triangular profile so that when force is applied they will grip the panel and not slip.
If the teeth become round or dirt gets in the gap between the teeth, their ability
to grip will decrease and it will be easier for them to come off. Clean and check
the teeth regularly.
Á Don't over tighten the bolt
Sometimes the bolts around the teeth that prevent the clamp from slipping
or coming off are tightened more than necessary. However, because pulling
force acts in the direction that the bolts are tightened, they can't come off even
if a large amount of force is applied. A bolt will get damaged if it is tightened
with more than the appropriate torque. Check clamp bolts regularly, remove
dirt and dust from the grooves and coat them lightly with machine oil. Replace
cracked or deformed bolts and nuts with new ones.
 Don't twist chains
Chains which transmit force to the clamps play an important role in body repair. Chains of a size specified for the alignment system have some margin as
far as strength is concerned. They do not break as long as they are used normally. However, it is dangerous to use a smaller chain than the size specified or
to use and old chain that has rust.
Using even a specified chain when it is twisted will apply undue force, and
even if it doesn't break suddenly its strength will be decreased. Always make
sure a chain is not twisted and protect it by occasionally applying some machine oil.
Repair of the underframe 9 - 24
(5) Pointers
1) How to determine the pulling direction
In the case of comparatively light front damage, repairs can be made by following a certain method regardless of
the condition of the damage. Let's take the example of a vehicle that received an impact from the front on the left
side on a diagonal. The left side of the front body is pushed toward the rear while the whole vehicle is bent toward
the upper right. The damage stopped at the side member and the toeboard has not been affected.
Since the impact was from the front left on a diagonal, one would think that the pulling direction is also the front
left on a diagonal and that since the vehicle is bent slightly up to the right force should be applied in a slightly
downwards direction. However, this would be wrong.
Even if the front is pulled on a diagonal from the front, the force will disperse to the direction of the side member
and the radiator support, which would not be effective. The clamps would most likely come off. If the pulling direction and the panel surface to which the clamps have been attached are not aligned, bending moment will act
on the clamps and the clamps will come off and the panel to which they were attached will be deformed.
It is best if the panel surface, surface to which the clamps are attached and the pulling direction are all aligned.
In other words, you should pull from virtually face-on despite the deformation of the side member that has been
pushed back. This will make the most effective use of the pulling force. In the same way, you should pull on the
deformed radiator support and cross member from virtually side-on while being drawn into the side member. For
the right side member that is bent slightly upwards, force should be applied from straight in front of the front. The
basic rule is to apply force from these three directions.
To put it more precisely, envisage the damage panel returned to its correct position. Decide on an angle which
will allow a straight pulling direction. This point requires considerable thought. Generally speaking, vehicle body
panels are a combination of vertical and horizontal panels, and because there are no panels in a diagonal direction always decide to pull from straight in front or from the side square on.
n The concept of pulling direction
Regardless of the directions of deformation, the pulling
direction should be straight against the body structure
×
Force is applied effectively.
Can be repaired even with
small forces
Since forces are dispersed,
stronger force is required
and there is a possibility of
clamp slips and generation
of deformations on the
normal area
Repair of the underframe 9 - 25
2) Spring back
When force applied by pulling is released, the panel which should have been fixed compresses and moves back
considerably. This is because of elasticity in the sheetmetal and the deformed area has not been able to stretch
due to work hardening of the deformed area.
Compression of a panel for a second time after force has been released when pulling is known as springback.
Repair work is more efficient if springback is minimized. The following three points are important for avoiding
springback.
À Extra pulling
Even if while pulling the panel has resumed its original measurements, if you pull an extra once or twice even if
there is springback you will get closer to the original dimensions.
Á Hammering while pulling
Because a deformed area that has work hardened (plastic deformation) is stronger, the deformation won't come
out even if you apply force by pulling and a panel in another place will be stretched.
Hammer the deformed site while applying some force, and if the residual force from the accident in the deformed
site is released while it is being aligned springback will decrease.
 Don't pull once
Pulling force not only corrects the deformed area but also pulls normal areas. Consequently, as long as the damage is not too minor, instead of applying a huge amount of force all at once, correct the deformation by pulling a
little and hammering, slacken the force to check the springback and then apply the force again.
If strong force is applied all of a sudden, the lower elasticity in the deformed area could cause cracking.
n Pulling pointers
Pull while hammering
the deformed sections
Pull a little further by taking
springback (moving back)
into account
Repair of the underframe 9 - 26
Handling of welding equipment 10 - 1
Chapter 10 Handling of welding equipment
Contents
1. Welding methods and systems ..................................................................................................................... 2
2. Spot welding .................................................................................................................................................. 2
(1) Principles and characteristics . ................................................................................................................. 2
(2) Equipment ................................................................................................................................................. 3
(3) Guns ........................................................................................................................................................... 3
(4) Welding conditions ................................................................................................................................... 4
(5) Conditions of use ...................................................................................................................................... 4
(6) Finishing checks ........................................................................................................................................ 5
3. MIG welding ................................................................................................................................................... 6
(1) Principles and characteristics . ................................................................................................................. 6
(2) Equipment ................................................................................................................................................. 6
(3) Unit . ........................................................................................................................................................... 7
(4) Weld wire supply systems ........................................................................................................................ 7
(5) Welding torch . ........................................................................................................................................... 7
(6) Gas cylinders . ........................................................................................................................................... 7
(7) Welding ...................................................................................................................................................... 8
(8) Conditions of use ...................................................................................................................................... 9
(9) Quality check ............................................................................................................................................. 9
(10) Safety measures . .................................................................................................................................. 10
4. Oxyacetylene gas welder ............................................................................................................................ 11
Handling of welding equipment 10 - 2
1. Welding methods and types
Spot welders and MIG welders are mainly used for replacing welded parts.
Welding using a spot welder, the same method used in the manufacture of new vehicles, is by far the more common method. However, because the performance of welders used for repair work is not as good as those used
during production, reliable repair, such as increasing the number of welds, is required.
A MIG welder is used for À sites that require strength; Á sites where spot welding can't be used; and  sites that
require patches and spot welds.
Joins made using an oxyacetylene welder, which used to be universally used, have insufficient strength so are
not used any more.
MIG welders are mainly used for aluminum alloy panels instead of spot welders. As for plastic, since most materials are thermoplastic, use a welder made for welding plastic that generates heated air. The welding rod should
be made from the same material as the material being welded.
Rustproofing is essential when welding metal panels. Make sure you apply an antirust agent used for welding
before you start welding.
2. Spot welding
(1) Principles and characteristics
Spot welding also goes by the name electrical-resistance welding. As the name suggests, the joint section of the
panel is melted and joined using heat generated by the resistance of the welding current through the panels.
Clamp the two panels using copper electrodes (tips). Once the panels are attached under pressure a strong current melts the welding surface of the panels. When the current is stopped, pressure is maintained until the weld
cools, which strengthens the weld (nugget).
One main feature of spot welding is that technically it is relatively simple and can be done quickly without much
experience. Because heat is applied to one site only, the heat has minimal effect on the surrounding area, thus
restricting distortion.
n Principles of spot welding
Applying
pressure
Tip
Applying
pressure
To be melted
with the heat
generated by
the resistance
Nugget
Panel
Applying
pressure
Tip
Applying
pressure
Power
supply
Applying
pressure
Applying
pressure
Applying pressure
Electroconductivity
Holding
Apply pressure on to the part
to be welded of the lapped
panels and they are adhered
so that the current flows easily.
With pressure being applied,
apply a large current so that
the contact surface of the
panels is melted and welded
together.
Even after applying current,
continue applying pressure
until the welded part cools
down so that the welded part
(nugget) will be reinforced.
Handling of welding equipment 10 - 3
(2) Components
A spot welder consists of a welding gun (arm) with electrodes, a transformer and a timer. Some welders
are integrated units where the transformer is built directly into the welding gun, while some use a separate
transformer.
Because in integrated welders the arms are heavier, a certain degree of strength is required to hold the gun at the
weld site. The weight is relieved by using an overhead boom.
Continuous welding causes the gun to heat. This is the reason some welders are water-cooled or air-cooled.
There are multi-functional spot welders that can also be used to weld washer studs used in body repair. Recently,
high quality welding has become possible using a system in which a computer controls the welding conditions
appropriate for the purpose, panel thickness and the material being welded.
n Spot welder components
Pressure lever
Pressure lever
Transformer Arm
Power
cord
(thin)
Arm
Transformer
Timer
(control unit)
Separate transformer type
Power cord (thick)
Timer
(control unit)
Built-in transformer type
(3) Gun
The arms on a welding gun must be able to press the electrodes against the workpiece no matter the location of
the site. Accordingly, a spot welder comes with a range of arms in different sizes and shapes. Use an appropriate
arm for the site.
Most arms are pressurized and held using air
Choose the shortest possible arm for the welding site.
1) Electrode tips
À In-line
Electricity won't flow if the upper and lower electrode tips pressed against the workpiece aren't in a straight line.
This also means that the arms are parallel. Strength is significantly reduced if the arms are on a slight angle.
n Electrode tips must be in line
No gap between panels
No rust, stain or paint film
on the joined surfaces
Handling of welding equipment 10 - 4
Á Tip shape
If the tip of the electrode tips do not make contact parallel to the
n Shape of tip
workpiece they cannot function properly. The prescribed shape
should be maintained as this has an affect on quality.
The diameter of the ends of the tips depends on the thickness of the
10 mm
5 mm
workpiece. If the panel is thick, the area of the tip will be larger as it
has to generate more current. The following formula is used.
120°
It should not be angled
due to wears or there
should be no dirt or
scratches
· Electrode tip diameter
2t + 3 mm = diameter t is panel thickness
* If sheets are of unequal thickness, calculate using the thickness of
the thinner sheet. For example, if there are sheets measuring 0.8
mm and 0.9 mm,
the formula is: panel thickness 0.8 mm × 2 + 3 = 4.6 mm
Use a tip cutter or file when: À the tip diameter is too big; Á the upper and lower tips do not engage properly;
and  there is dirt on the surface.
If a tip is worn or bent replace with a new tip.
À Pressure (welding force)
Since quality will be affected if a certain amount of pressure is not exerted during spot welding, before welding
check the pressure using a test piece with the same thickness as the welding site. Old panels due to be discarded
are useful for this purpose.
(4) Welding criteria
Criteria to be considered when spot welding are the weld current, time, pressing force and tip diameter. These
vary depending on the thickness of the panel.
These criteria can also vary due to the characteristics of the spot welder being used. Optimum results can be obtained by inputting data such as panel thickness so that the welder automatically controls these values.
(5) Conditions of use
1) Surface conditions of the joined panels
There should be no gaps, paint or rust in the surfaces to be joined. The tips must be pressed tightly against the
panel surfaces.
2) Rustproofing treatment on the surface
Treat the surfaces to be joined by applying a rustproofing sealer beforehand. Rustproof sealers used for welding
conduct current.
3) Weld pitch
When spot welding continuously, current diversion will occur if the spacing (pitch) between the present site
and next site is short. Some of the current will be lost because it will try to reach the previous weld site where
resistance is low. Since there is not the expected level of current flowing, the strength of the latter site will be
lowered.
It is for this reason that you should weld while maintaining certain spacing. Spacing between weld sites should
be more than three times the diameter of the weld nugget.
Handling of welding equipment 10 - 5
n Weld pitch
Pitch
Current diversion
will occur if the
spacing (pitch) is
short.
4) Number of weld points
Refer to the body manual for the locations of the spot weld points. Make a weld point in the center of the
flange.
In vehicle repair it is often not possible to retain the spot points of a new vehicle. Taking the performance of a
spot welder used for repair into account, around 1.3 times as many weld points as that on a new vehicle will
ensure that strength is maintained. In MIG plug welding the same number of weld points as a new vehicle is
acceptable.
5) Panel thickness limit
Although it can vary depending on the performance of the spot welder being used, generally spot welding should
be done on panels no thicker than around 3 mm. MIG plug welding should be used for greater thicknesses.
6) Heating of tips
The electrode tips will become heated if welding continuously. Because when tips heat up À the current is impeded; there is Á friction; and  "dishing" occurs, either take a break after a certain number of times or use a
welder with a cooling attachment.
(6) Inspecting the finish
There is a limit to the results of spot welding that can be ascertained in a visual check. Although a visual check will show
n Spot weld tests
Destruction of test piece
Welded point
spacing and dishing, it won't show any cracks.
For this reason, it is important to weld a test piece beforehand
under the same conditions, remove it and check its strength.
Spot weld
Weld test pieces with the
same thickness as the panel
to be welded.
Then separate the test pieces.
Chisel and hammer can be used
to remove the welded point.
Handling of welding equipment 10 - 6
3. MIG welding
(1) Principles and characteristics
In MIG welding, the welding wire is the electrode and is melted by the heat of the arc within an inert gas shield. It is
also known as semi-automated welding as when the switch is turned on the wire is automatically fed through.
TIG welding also uses the heat generated by the arc. The electrodes are tungsten so they do not wear. The arc
produced by the electrodes melt the welding rod. This requires the use of both hands.
The small torch used on one side only means that MIG welding can be used in a variety of sites. Another feature
of MIG welding is that it can be used to weld panels of unequal thickness.
A MIG welder is used for sites that are inaccessible for spot welding, sites that require strength, and for patches
on panels.
Distortion is minimal and basic operation is relatively simple. A direct current power source of
200 V is used.
n Principles of MIG welding

With switch ON,
the current flows to
emit the arc sparks.
Œ
Plug welds (spot welds) and seam welds (butt
welds) are mostly used when repairing panels.
Welding wire
Plug welds are made at sites that are inacces-
Panel
sible for spot welding. A plug weld is made by
removing the paint film, making a hole in the upper panel and then filling up the hole. A seam
weld is where a 1 – 2 mm gap between panels
is filled in.
Wire melts with spark
heat and drops onto
the part to be welded.
This will cause shortcircuit of arc and thus
arc discharge is stopped.
Ž
With large current
flow, the welded
part is cut with
magnetic force.

Arc discharge starts
again.
Magnetic force
If there is a site where it is difficult use these
methods, make a fillet weld on the end of two
overlapping panels.
(2) Components
A MIG welder consists of the weld torch, which
Regulator
Main unit
feeds the wire and shield gas, an earth clamp, a
Wire supply
devise
Torch
section
welders have an external wire drum), and a gas
cylinder positioned to the side.
Carbon dioxide gas
Switch
Tip
Welding wire
Panel
Earth clamp
Power unit
Control unit
Carbon dioxide
gas cylinder
mechanical unit with a built-in wire drum (some
Handling of welding equipment 10 - 7
(3) Main unit
Voltage, current, and the timer are controlled within the main unit. By calibrating the control panel, the welder
will set the appropriate values.
(4) Wire feed unit
This unit consists of a wire reel and a wire feeder. The wire reel is housed either in the main unit or in a separate
unit.
The wire comes in a variety of diameters and materials. Wire diameters include 0.6 mm and 0.8 mm, and if the
workpiece is an aluminum alloy panel, aluminum wire should be used.
Check the wire feed unit daily and remove dust and oil.
(5) Torch
When the switch is pressed, it feeds the wire through which the elec-
Wire
Current
Gas
tric current passes as well as gas through the nozzle. Since it is used
as a conduit for electricity and gas and is exposed to high temperatures, the torch is the most susceptible to wear of all MIG welding
components.
(6) Gas cylinder
The abbreviation MIG stands for Metal Inert Gas, which is used to
form a shield around the weld site. This prevents rust, minimal gas
is used and it produces a tidy finish.
However, argon, an inert gas, is expensive and though it is used
for aluminum alloys, an activated gas (metal active gas) or a gas
made up of a mixture of carbon dioxide and argon is used for normal sheetmetal. Since the majority of welders use carbon dioxide
gas it is more correct to call this welding MAG (metal active gas)
welding. However, the term MIG welding is commonly used for this
method.
This commonly used carbon dioxide gas has a specific gravity of
1.529 and with a melting point of -56.6 ˚C. It is a gas at room temperature. Carbon dioxide gas is colorless, transparent, tasteless and
odorless.
The gas cylinder should always be upright. Use a belt or chain to
stabilize it and prevent it from tipping over. When exchanging the
cylinder make sure it does not receive an impact.
Gas cylinders are color coded to allow immediate identification of
the contents. Carbon dioxide cylinders are green and argon gas cylinders are grey.
Cylinders are fitted with a gas regulator. Lower the cylinder pressure
(2 – 3 kg/cm2) and adjust the gas flow rate so that it is appropriate for
welding. As evaporation heat causes carbon dioxide gas to freeze
when it leaves the cylinder, so a heater is attached to avoid this.
Check for gas leaks from the regulator daily using a soap and water
solution.
Switch
Nozzle
Handling of welding equipment 10 - 8
(7) Welding
1) Seam welds
Seam welding is when two overlapping panels are welded. Secure the
two panels leaving a gap of 1 – 2 mm
between them, and weld continuously
while filling up the gap.
Because heat will cause distortion in
the surrounding area if you attempt to
weld a long distance at once, make a
weld, stop for a moment and then continue with suitably spaced intervals.
2) Plug welds (spot welds)
Plug welds are made to supplement
welding done using a spot welder.
Plug welds are made at sites where
there are a number of panels to be
joined, sites that require strength, and
sites where spot welding is difficult.
First, make a hole in the top panel
at the weld site. The diameter of the
hole varies depending on the thickness of the panel. A diameter of 5 – 6
mm is suitable for a 0.8 mm-thick steel
sheet.
3) Fillet weld
A fillet weld is used to weld the ends
of one panel laid on top of the other.
Handling of welding equipment 10 - 9
(8) Conditions of use
1) Weld area
Do not leave a gap between panels and perform the necessary rustproofing treatment. Remove any rust or moisture.
2) Distance
n Distance from torch
If the distance between the end of the tip in the nozzle and
the workpiece is too far the distance from the wire tip will
Tip
also be far. This will reduce the current, which will result in
shallow penetration. Conversely, if the distance is too short,
Nozzle
the large amount of current will result in deep penetration.
Accordingly, if you make allowance for this you will be able
to weld panels of different thicknesses without having to
Extension
CO2
adjust the current.
CO2
Wire
Panel
3) Alignment
À Plug weld
Position the tip of the wire in the nozzle so that it is perpendicular to the center of the hole being welded. If it is not in
the center there will be insufficient penetration to the lower
panel.
Á Seam weld
n Torch angle
5 - 20°
Put the wire tip in the middle of the bead. The torch should
be at a 5 – 20˚ angle to the direction of the weld.
 Fillet weld
First, spot weld in a way of plug welds leaving a certain
distance apart and then weld in a way of seam welds to fill
up the gap.
(9) Quality check
n Plug weld diameter
8 - 10 mm
1 - 2 mm
To check whether or not the weld is correct, use a panel
offcut making it the same thickness, etc and check using a
lapped splice. Check the size of the weld diameters on both
sides and then conduct a twist test.
The diameter of a plug weld should be 8 – 10 mm (2 – 4 mm
on the rear panel), and should be raised 1 – 2 mm.
2 - 4 mm
Handling of welding equipment 10 - 10
(10) Safety precautions
1) Welding arc and sputters
Arc welding produces a strong arc that contains ultraviolet rays. Place the workpiece so that you don't have to
look directly into the arc. Wear welding gloves and do not expose skin directly, including the arms. Exposed skin
can be burnt by not only the arc but also by weld sputters. Make sure work clothing is buttoned or zipped.
2) Fire
Since welding generates sparks, make sure there are no hazardous items like gasoline or thinner in the work
area.
3) Gas cylinder
The gas inside the cylinder is liquefied and compressed. Use a cylinder that is not damaged, do not subject it to
any impact and avoid sudden temperature rises, such as exposing it to direct sunlight.
Handle carefully when replacing or shifting.
Handling of welding equipment 10 - 11
4. Oxyacetylene welder
Oxyacetylene welders were once commonly used. However, this type of welding is no longer used in body repair
due to distortion caused by heat, the occurrence of rust after welding, and insufficient strength. Shrinking is also
mainly carried out using electrodes. Today, this is limited to heating or cutting panels no longer in use.
n Gas welder components
À Oxygen cylinder
Oxygen valve for cutting
The cylinder contains oxygen compressed to approximately
150 kg/cm2. The cylinder is black.
Á Acetylene cylinder
Torch head
Oxygen tube
Oxygen hose plug
Acetylene is dangerous. It is stored in a cylinder that
contains a porous material and is dissolved in other
chemicals. Pressure is 15.5 kg/cm2. An acetylene cylinder is
brown.
Waste heat tube
Burner tip
Cutting torch
Acetylene
Oxygen valve
for preheating hose plug
Acetylene valve

 Oxygen valve
Ž
‘
à Acetylene valve
Ä Oxygen regulator
Lowers and maintains the pressure of the oxygen as it
“
’

leaves the cylinder.
Å Acetylene regulator
Lowers and maintains the pressure of the oxygen as it
leaves the cylinder.
Æ One-touch hose connection
The hose used for oxygen is also black and the acetylene
hose is also brown.
Ç Torch
The amounts of oxygen and acetylene can be adjusted
separately. There are torches used for cutting and torches
used for welding.
Welding torch

Œ
Handling of welding equipment 10 - 12
Replacement of welded panels 11 - 1
Chapter 11 Replacement of welded panels
Contents
1. Replacing welded panels . ............................................................................................................................. 2
(1) Assembly replacement ............................................................................................................................. 2
(2) Patch replacement . ................................................................................................................................... 2
2. Order for replacing welded panels ............................................................................................................... 4
(1) Removing damaged parts ........................................................................................................................ 4
(2) Preparation for fitting .............................................................................................................................. 5
(3) Fitting ......................................................................................................................................................... 6
3. Bonded panels . .............................................................................................................................................. 9
(1) Structural adhesives ................................................................................................................................. 9
(2) Bonding methods ..................................................................................................................................... 9
Replacement of welded panels 11 - 2
1. Replacing welded panels
Welded panels can be replaced by either using a supplied assembly or by removing one section and replacing
that section with a patch.
(1) Assembly replacement
This method involves replacement using a supplied panel and is used for parts such as the radiator panel, front
wheel apron, rear skirt and roof panel.
(2) Patch replacement
This is when the damaged area is cut out and replaced with a patch.
In general, if a reinforcement has a complex construction, rather than replacing the whole reinforcement a section is cut out and replaced with a patch. This is a more efficient method. Accordingly the rear quarters, side sills,
and center pillars can be easily replaced using this method. In addition to showing structure and strength, a body
manual also shows the best sites for cutting and the number of weld points.
The basic rule of thumb is to cut out leaving a 50 – 100 mm margin to a panel corner or welded section. Patches
are best used on sites where there are no reinforcements on the under side and the length of patch welding is
kept to a minimum.
When replacing both the inner and outer panel of a pouch-shaped part like a pillar, stagger the cuts of the inner
and outer panel by 30 – 50 mm. Leave inner panels on the body side long and shorten upper outer panels.
Outer pillar
30 - 50 mm
Inner pillar
Replacement of welded panels 11 - 3
1) Joining
Butt welds are often used when replacing parts that have been cut out. MIG weld the gap between the new cut
panel and the old panel on the body. After welding the key spots, fill in the gaps and weld the whole part.
A seam of the thickness of an air saw blade is appropriate. You can either put the new and old part together and
cut once or cut using accurate measurements. When cutting using measurements, if the cut piece is too short
there will be a gap between the panels. To avoid this, leave an extra margin when cutting and make adjustments
at the end.
Similar to
thickness
of a saw
blade
Body side
New part
Put the new and old panels Positioning with a space
together and cut once
similar to thickness of
a saw blade
Spot weld with appropriate
interval to fill in the gaps.
2) Flanging
Create a flange on one of the panels using a flanging tool and attach by either MIG welding a fillet weld or by
using a structural adhesive.
This is restricted to sites where flanges can be made. Ordinary flanging tools are used on flat surfaces. However,
there are some tools used in panel bonding that can be used on crowns and corners.
3) Adding reinforced panels
Use leftover parts of new panels that have been cut for sites that require reinforcing. Cut the same press line to
a length of around 50 mm and weld the part under the body side as a reinforcement panel. Strength is further
improved by laying the new panel on top and making a butt weld. This method is suitable for the side sill and
side frame.
Cut the part
where a new
part is not used.
Cut
Cut
Approx.
50 mm
Reinforced
panel
Approx.
50 mm
Body side
Reinforced
panel
Remove the paint film and
paste a spot welding sealer
Replacement of welded panels 11 - 4
2. Order for replacing welded panels
(1) Removal of damaged sections
1) When to remove parts
Unlike a bolted on panel, once a welded panel is fitted its position cannot be adjusted. Therefore, this work
needs to be done carefully.
The welding of new panels should be done in association with body alignment. If the measurements of underframe parts can be corrected during alignment, remove panels that will be replaced with new panels.
However, if this is done too soon, the dispersion of
force to surrounding parts during the remaining repair
work will not go well and could take longer. Conversely,
if you wait until all body repairs have been completed,
it will take longer.
The basic rule of thumb is to remove parts once the
measurements of key points for welded parts have
been corrected or when they align perfectly with the
measurements of the adjoining panels.
2) Rough cuts
Decide on the sites to be cut out and make a rough
cut.
Since panels that are to be removed don't have to be repaired, if necessary to make repair work more efficient
cut out these sites before the panels are removed.
When make a rough cut, be careful not to cut wire harnesses and tubing on the underside or in pouch structures. Reinforcing materials filled inside pillars must
not be burned.
When working on a particular vehicle model for the
first time make sure you refer to the service manual
beforehand.
When making a rough cut for a patch, leave a margin of
an extra 30 mm on the body side.
Use an air saw or plasma cutter for cutting. If using a
tool that produces a lot of noise, insert ear plugs or
wear ear muffs.
Do not remove the panel being replaced until the dimensions have been corrected.
Replacement of welded panels 11 - 5
3) Drilling out spot welds
Using a drill or a dedicated spot drill, remove nuggets on
spot welds by grinding.
Make sure you grind only the upper panel and not the lower
panel. A spot drill can be adjusted to the thickness of the
panel.
Do not use an ordinary blade with a pointed tip. Use an almost flat dedicated blade (spot cutter).
When there are three layers and the panel being replaced
is under the remaining panel, go all the way through. Use
a MIG welder, weld a plug into the hole in the remaining
panel.
4) Taking off the panel
Insert a chisel into the gap in the panel on which you used
the spot drill, tap it with a hammer and take off. Apply force
in the direction in which you are taking off the panel so that
the panel on the remaining side is not marked.
Also use a chisel and hammer to take off chips from the old
panel that remain on the edge.
Lastly, with a hammer and dolly repair any dents or bumps
formed in the welded part.
(2) Preparation for fitting
1) Treating panels
After removing the panel, use a belt sander to smooth any
spot-weld traces on the panel to be used.
Repair damage to spot welds or pierced sites that occurred
during removal using MIG welding.
Smooth using a belt sander
Replacement of welded panels 11 - 6
2) MIG plug weld holes
Make a hole about 6 mm in diameter in the upper panel at
sites that are to be welded with MIG plugs. Use an air drill or
punching tool.
Using a belt sander, remove paint film on the body side and
new part side taking off more paint than the size of the hole.
Use a drill to make holes
3) Preparation for the new panel
When cutting out to make a patch, cut it out with an air saw
or plasma cutter leaving a margin of around 30 – 50 mm on
the body side.
(3) Fitting
1) Trial fitting and final cut
Trial fit the new panel by clamping it in place.
If the panel needs cutting, place the two panels one on top of
the other and cut simultaneously using an air saw. If this is
not possible, cut in line with the final measurements. Do this
gradually, not in a single step.
In the trial fit, check the measurements and fit any related
panels, adjacent panels and bolt-on panels and looking at the
whole arrangement determine whether they are aligned.
Using a tram gauge, compare with the reference values in
the body dimension diagram.
If the position is fine, take it off and prepare for welding.
Replacement of welded panels 11 - 7
2) Paint removal and rustproofing
Remove any primer coated on the new panel and paint on the weld sites on the body side, on both the front and
back. Use a belt sander.
Apply a welding rustproofing sealer to the area where the welded panel will be placed.
If there are sites requiring a coating of sealer that will be hard to get to once the welding has been done, apply
the sealer beforehand.
Before fitting, compare it with the old part to see whether it has enough small panels, such as reinforcements.
If there aren't enough and if the reinforcements in the old panel are not marked or damaged, take them out and
weld them to the new panel first.
Rustproofing weld sites
3) Number of weld points
Although in spot welding the number of weld points also depends on the power of the welder and repair site,
increase the number of weld points by about 30% so that outer panels have 10% more weld points than a new
vehicle and underframe panels have 30% to 50% more weld points. Generally, the number of weld points is increased because power when spot welding is different from the time of manufacture.
In the underframe there are sites where panels are put on top of each other. If the total panel thickness is more
than 3 mm, choose MIG plug welding in preference to spot welding.
When MIG plug welding, the same number of points as on a new vehicle is fine.
In principle, the sites of the spot welds should be different from the sites on the old panel.
4) Preparation for welding
Cover the surrounding panels and glass with weld protection sheets so that they are not marked by sputters or sparks
during welding.
When spot welding, use a part of an old panel or a piece
cut off the new panel to test weld using the same material
and panel thickness. Check the nugget shape and size and
strength of the test piece.
n Protective sheet
Replacement of welded panels 11 - 8
5) Tack welding
Weld not from the edge inward, but weld first at key points leaving a space in between. Remove the weld clamps
when the panel stops moving.
Check reference measurements and arrangement. If there are no problems complete the welding.
* Key points are corners and sites where the shape changes. For long parts key points are evenly spaced points. Weld
alternately, rather than in one direction.
6) Welding
Fill in the spaces between the key points. As with sites where the panel has been cut out to be patched, once
welds have been made at intervals weld the spaces in between.
The various spot welder arms and air clamps can be used effectively for different repair sites.
The basic rule is to use a MIG welder for any sites where spot welding is not possible.
Use spot and MIG welding as appropriate
7) After treatment
After welding, check the various measurements.
Also check to see whether welding has caused any
distortion.
Make a visual check of the weld sites to see whether the welds have adequate strength.
Use a disc sander or belt sander to smooth the
surface of MIG plug welds and butt weld sites. Be
careful not to grind too much.
Because the heat generated through MIG welding can cause distortion, if necessary repair using
hammering.
Deburr spot welds using a sander also.
Then apply a sealer, antirust agent or foaming
agent.
Apply more rustproofing than would be used for a
new vehicle. This is because welding makes metal
prone to rusting.
Smooth using a belt sander
Replacement of welded panels 11 - 9
3. Bonded panels
(1) Structural adhesives
There are two methods for bonding panels using a structural adhesive: À using only an adhesive; and Á combining an adhesive and welder. The former method is called panel bonding while the second is called weld
bonding.
Using an adhesive has the following advantages: À stress is evened out; Á welded parts do not deform; Â they
have excellent water-tightness and air-tightness; and à it is easy to join different materials. The disadvantages
are that thermal resistance and repeat bonding are not very good and hardening takes time. Bonding provides
similar or superior strength to spot welding because unlike spot welding where spots are welded it is the surface
that is joined.
(2) Bonding methods
When cutting out and making a patch, there are a number of methods depending on the repair site and strength.
The two main methods are attaching a reinforcing panel to the under side of the join and welding, and making a
flange to lap the join. In a flange operation, there are various lines, though this can also be remedied.
Because adhesives used for repair take time to harden the panels must be secured to a firm surface or clamped.
This can be done in various ways. Methods include combining spot welding and rivets, using special fastening
clamps and combining spot welding and adhesive.
When repairing panels using the bonding method, positioning must be precise and the panels must be securely
fastened until the adhesive has hardened completely.
There are cases where due to a huge change in temperature the difference between the cut out sheetmetal and
swelling or contraction of the filler after painting, making the line visible as a result. Ways to counter this include
selecting an appropriate filler and thorough implementation of forced drying.
Long panels cut out and replaced are prone to distortion caused by heat. There is also a higher risk of rusting.
n Example of weld bonding
À Attaching to the back of a panel
Œ
Make a piece with the same shape for attaching to the back of the body side
Spot
welding
and the side of the part being replaced and glue using adhesive.
Spot weld the first of the two pieces to be worked.
Fasten rivets on the surface of the second piece.
Á Joggling
100 mm interval
(except line
sections)
Make a joggle (slight step) on the side of the replacement part and glue it to
the body using adhesive.
After clamping the cut surface with a special vice, fasten using rivets.
Use a flanging tool that can also be used on crowns and corners.
3 mm
40 mm backing

Riveted after
fixing with vice
 Standard panel replacement
Examples: Roof panel, door outer panel.
Advantage: Fewer weld points
50 mm
interval
Riveted:
50 mm
interval
Replacement of welded panels 11 - 10
Repairing aluminum alloy and plastic panels 12 - 1
Chapter 12 Repairing aluminum alloy and plastic panels
Contents
1. Aluminum alloys ............................................................................................................................................ 2
(1) Sanding . .................................................................................................................................................... 2
(2) Repair work ............................................................................................................................................... 2
(3) Heating . ..................................................................................................................................................... 2
(4) Welding ...................................................................................................................................................... 2
(5) Substrate treatment .................................................................................................................................. 3
2. Repairing plastic panels ................................................................................................................................ 4
(1) Minor damage ........................................................................................................................................... 4
(2) Major damage ........................................................................................................................................... 4
(3) Cracks and holes ....................................................................................................................................... 5
Repairing aluminum alloy and plastic panels 12 - 2
1. Aluminum alloys
In Subaru vehicle bodies, aluminum alloys are used in the
hood and the trunk lid.
n The hood of the first Legacy (BP/BL)
model was made from aluminum alloy
(1) Sanding
Aluminum alloys possess different properties to steel and though the same basic body repair methods are used,
several precautions are required.
First, because the surface is soft, deep sanding marks are easily made.When removing paint, use paper with a
finer grit size than paper used for sanding sheetmetal.
The surface of aluminum soon oxidizes and though no further corrosion occurs, paint does not adhere well to this
oxidized film. Consequently, carry out surface preparation straightaway.
(2) Repair work
Only sites in aluminum alloy panels with elastic deformation can be repaired by panel beating. Repairing sites
with plastic deformation is very difficult.
Strength is also lowered as a result of hammering and repeated pulling. Hammers leave marks and there is considerable stretching. Therefore, it is preferable to use a wooden or plastic hammer.
Also, when an aluminum alloy is in contact with iron, the aluminum will rust as a result of being in contact
with another metal. An aluminum alloy may rust because of iron powder adhering to tools used everyday for
sheetmetal.
There are stud welders that have special aluminum pins for use on aluminum alloys. The increasing use of aluminum alloy panels has seen the development of more and more equipment for aluminum alloys and most parts
that are replaced can be repaired.
(3) Heating
When working with aluminum apply moderate heat as aluminum can break if force is applied under low temperatures. The right temperature is roughly the same as when you touch a surface wearing a heavy duty cotton
glove and it feels hot.
Aluminum alloys are good conductors of electricity. Since the heat of a heated area spreads, make sure that only
a small area is heated and that the temperature isn't too high.
Though aluminum is easy to repair because it doesn't crack when heated, there is a limit to how hot it can be
heated, which if exceeded with lower strength. Despite some variation depending on the particular aluminum
alloy, the threshold is 200 – 250 ˚C. Check the temperature with a contactless thermometer.
(4) Welding
Since aluminum alloys require a large current due to their electroconductivity, welding cannot be done using a
spot welder used for repairs. There is a dedicated MIG welder that uses aluminum wire. If using this, use argon
gas as the shield gas as you cannot use carbon dioxide gas.
Repairing aluminum alloy and plastic panels 12 - 3
(5) Surface preparation
Follow the same procedure as for sheetmetal: feathering, priming, and filling. Because some substrate paints can
be used on aluminum alloy as well as sheetmetal and others are made for aluminum alloy only, check the paint
manufacturer's specifications.
n Pointers when repairing aluminum alloy
Grinding
Panel
beating
Heating
Welding
Substrate
Use paper with a finer grit size than paper used for sanding sheetmetal:
Once the substrate appears, immediately carry out surface preparation:
Only possible for elastic deformation
Replace the part in case of plastic deformation
Use a wooden hammer or plastic hammer:
Development of repair tools are in progress:
Because it is softer
prone to rust
Easy to stretch and to leave hammering marks
Studs, etc.
Easy to repair when heated
Temperature limits are 200 °C (6000 type alloy) and
250 °C (5000 type alloy):
Excessive heating deteriorates strength.
Use a radiation thermometer
Use a dedicated MIG welder:
Spot welding is impossible because of their electroconductivity.
Use aluminum wire and argon gas
Primer for aluminum
Repairing aluminum alloy and plastic panels 12 - 4
2. Repairing plastic panels
In some instances plastic panels are used for the rear gate.
n Rear gate R1 (RJ)
Examples of plastic bumpers often requiring repair are listed below.
(1) Minor damage
Wash damage affecting the luster caused by moderate contact, sand with P600 paper and then gently polish the
damaged area.
(2) Major damage
If the bumper has scratches, wash with water and then cut off any protrusions with a knife. Sand with P120 – 600
paper.
Repairing aluminum alloy and plastic panels 12 - 5
(3) Cracks and holes
When repairing holes and cracks, fill the holes or cracks with a
n Cut a guide slit
welding rod made from the same material using a welder used
(3)
for plastic parts (heat gun).
(1)
After degreasing, cut a guide slit into the hole or crack, and create a V-shaped groove using a knife or sander. Sand the surface
of the groove using P60 paper, degrease and clean.
Using a heat gun and a welding rod of the same material, fill
in the groove while melting the damage site at the same time.
Leave until it returns to room temperature. Hold the heat gun
(2)
(4)
(1) Painting surface
(2) PP base
(3) 20 - 30 mm
(4) 3 mm
about 1 – 2 cm from the weld site, and fill in when the bottom of
the welding rod and the damaged area melt together.
n Fill in the groove using a heat gun
Check that it has returned to room temperature, and remove any
excess from the surface using a knife or a cutting disc. If using a
(2)
power tool, use at speeds of below 1,500 rpm. If the speed is too
high the heat may cause melting.
Sand the surface with P240 paper.
(1)
Mask, degrease and clean.
If the plastic is polypropylene, paint with a PP primer before
(2)
starting the painting process.
(3)
(1) Welding rod
(2) Area to be welded
(3) Cross-sectional view
• Melt the site shown by the shaded area
• To retain strength, do not melt until the
welding rod starts to flow
n Remove excess from the surface
and sand with paper
Repairing aluminum alloy and plastic panels 12 - 6
Quality inspection 13 - 1
Chapter 13 Quality inspection
Contents
1. Wheel alignment ............................................................................................................................................ 2
(1) Body and wheel alignment ...................................................................................................................... 2
(2) Factors and testing ................................................................................................................................... 2
2. Adjustments to electrical fittings and headlights ....................................................................................... 3
3. Completion checks ........................................................................................................................................ 3
4. Panel arrangement . ....................................................................................................................................... 4
5. Handling air tools . ......................................................................................................................................... 5
6. Maintaining quality . ...................................................................................................................................... 5
Quality inspection 13 - 2
1. Wheel alignment
(1) Body and wheel alignment
The suspension determines the position of the wheels. In a unitized body, the suspension is attached directly to
the body or via a subframe. Consequently, if there is deviation in the body, the wheels will also be misaligned.
When the repairs have been completed, check the wheel alignment of vehicles that have had damage to the
wheel apron and side frame.
The set values for wheel alignment are the same as those for a new vehicle. If the tires or wheel sizes have been
changed the set values will be different. The values will also be different if the parts that make up the suspension
are damaged or worn.
(2) Factors and testing
The factors in wheel alignment are toe-in, camber, caster and the kingpin angle. Misalignment or tilt in the front/
rear vehicle axis is also an important factor that affects all four wheels.
Use a four-wheel alignment tester under prescribed conditions (empty vehicle on horizontal site) to measure and
test the wheel alignment. If there is misalignment, adjust while referring to the wheel alignment chapter in the
Chassis edition of the service manual.
However, there are occasions when realignment exceeds the scope of adjustment, or adjustment is not possible
for structural reasons. This requires alignment of the body to which the suspension is attached. Do this in accordance with the set values.
Areas at the front that affect wheel alignment the most are the area around the strut mounts and the area near
where the front arm is attached. The wheel apron and the side frame are the panels that have the largest effect. At
the rear, deformation of panels around where the suspension is attached affects alignment.
* Empty vehicle: Empty the trunk but fix the spare tire, jack and repair tools and fill up the fuel tank.
n Main factors in wheel alignment
Camber
Caster
Kingpin angle
F
Toe-in
Front wheel steering angle
(turning radius)
a
b
Toe = b-a
In some cases, it is indicated with this angle
* The added angle between the camber and kingpin is called included angle
n Ensure consistency for all four wheels
Axle inclination
Axle
declination
* Not only the individual elements, but the relationship of
each position and balance are also important
Quality inspection 13 - 3
2. Adjustments to electrical fittings and headlights
It is important to check the operation of the various electrical parts once repairs have been completed. Headlamps often have to be replaced in association with repairs, and also look out for incorrect connection and poor
contact.
Safety regulations determine the direction and range of illumination for headlamps. When headlamps are removed and replaced as a result of repairing a radiator panel, test and adjust the headlamps using a headlamp
tester while referring to the chapter on lighting systems in the Body edition of the service manual.
Height: Within 1/5
Right side: Right: 10 cm, Left: 20 cm
Left side: Left-right: 20 cm
10 m
3. Completion checks for repair sites
Make a visual check of the repair sites and adjacent panels to check weld finish and to see if bolts have been
tightened.
Check for water leaks by hosing damaged vehicles that have had window glass and door weather stripping replaced and repairs to panels associated with the passenger compartment and the trunk.
Road test all the cars when repairs have been completed, and check the operation of the engine, meters, transmission, brakes, steering, etc. Also check for any strange noises or vibration.
Drive carefully so as to avoid an accident.
Quality inspection 13 - 4
4. Panel arrangement
Refer to the body repair manual for the reference values for the panel arrangement.
They are set taking adjacent panels into account, and there are cases where the gaps specified in the reference
values cannot be rigidly maintained. Although there is some variation depending on the site, the permissible limit
is ± 0.5 – 1.0 mm.
(H)
(I)
(E)
(D)
(J)
(C)
(F)
(A)
(B)
(K)
(G)
(A)
Site
Reference value
Between front hood and front grille
6.0 ± 1.0 mm
(B)
Between front hood and headlamp
6.0 ± 1.0 mm
(C)
Between front hood and front fender
3.5 ± 1.0 mm
(D)
Between front hood and front fender (end only)
4.8 + 0.7 – 1.0 mm
(E)
Between front fender and front pillar
3.0 ± 1.0 mm
(F)
Between front fender and front door
4.0 ± 1.0 mm
(G)
Between front fender and side sill
3.0 ± 1.0 mm
(H)
Between roof and front door sash
5.0 ± 1.0 mm
(I)
Between front door sash and rear door sash
5.5 ± 1.0 mm
(J)
Between front door and rear door
4.5 ± 1.0 mm
(K)
Between front door and side sill
6.0 ± 1.0 mm
Quality inspection 13 - 5
5. Handling air tools
Daily maintenance of air tools is vital so that they can be used when required.
À Use air at the prescribed pressure for each tool.
Á Do not use tools for any other purpose.
 Use clean air.
à Clean, check and oil each tool as appropriate after use and at the end of the working day.
6. Maintaining quality
Maintaining quality is based on the established standard process and is achieved by repairers with recognized
skills making repairs in accordance with the various manuals for devices, equipment and materials.
As a result, precision is further enhanced by getting a third party to check quality based on a checklist.
Established
standard
process
Quality
Outstanding
facilities,
equipment
and
materials
Qualified
engineers
Quality inspection 13 - 6
Appendices 1
Appendices
Contents
1. Auto body repair workshop equipment ....................................................................................................... 2
(1) Hoist ........................................................................................................................................................... 2
(2) Garage jack ................................................................................................................................................ 2
(3) Air compressor .......................................................................................................................................... 2
(4) Power supply unit ..................................................................................................................................... 3
(5) Headlamp tester ........................................................................................................................................ 3
(6) Wheel alignment tester . ........................................................................................................................... 3
(7) Dust collection system ............................................................................................................................. 4
(8) Drier ........................................................................................................................................................... 4
2. Related technical resources .......................................................................................................................... 5
(1) Body repair manual .................................................................................................................................. 5
(2) Service manual - Body ............................................................................................................................. 5
(3) Service manual - Chassis ......................................................................................................................... 5
Appendices 2
1. Auto body repair workshop equipment
The following are the main pieces of equipment and systems required by an auto body repair workshop
equipment.
(1) Hoist
A hoist raises a vehicle using an electric motor or an
air-powered hydraulic pump. They are not the same
as hoists used for maintenance and many are pantograph hoists that are part of a body repair system.
By raising a vehicle, the repairer does not have to
assume unnatural postures while working on the
side or underneath a vehicle. The basic rule is not to
crawl under the hoist and to check for safety before
and after use.
(2) Garage jack
A garage jack uses manual power or air power to
raise a vehicle.
Do not go under a vehicle that is raised on a jack.
Be sure to support the vehicle with a rigid rack and
check for safety.
(3) Air compressor
Most power tools are driven by compressed air. A
compressor operates using an electric motor.Although it depends on the number of repairers and
the number of tools being used, the compressor
should be set at 1.5 – 2.0 HP per individual repairer.
Since work stops if the compressor shuts off, a reliable daily backup and maintenance system is required, including all of the air piping.
Appendices 3
(4) Power supply unit
A power supply unit is a power supply system that
integrates power supply, air and dust suction ducts.
Many have a light that illuminates when the power
is on. The unit is installed on the ceiling, a pillar or on
a wall and cords and hoses can be pulled from the
unit as needed.
(5) Headlamp tester
A headlamp tester measures whether the illumination range of the headlamps conforms with
standard.
(6) Wheel alignment tester
Measures each of the factors for wheel alignment
separately for each of the four wheels. It is also
known as a four-wheel alignment tester. It can show
differences between actual values and reference
values.
Appendices 4
(7) Dust suction system
It sucks up and collects sand and dust generated
when sanding body filler from the floor. When using
a dust suction sander, put the tip of the hose into a
gap in the mesh panel in the suction inlet in the floor.
There are other portable cleaners (for one sander or
several sanders), as well as dust collection systems
with ducts in the ceiling or wall that collect dust from
around 10 sanders.
(8) Drier
Accelerates putty drying. Driers have various heat
elements, including infrared lamps and halogen
lamps. They range in size from hand-held dryers to
drier banks.
Appendices 5
2. Related technical resources
When working on a model or a repair site for the first time, gather information by referring to technical resources
on how to proceed with the repair work. Related items are as shown below.
(1) Body repair manual
Sites and materials
Plastic parts, zinc-plated sheetmetal, high tension steel
Rustproofing agent treatment sites
Sealers, rustproofing wax, undercoat
Panel components and cross-sectional diagrams of interlocking panels
Vehicle reference values and dimensions
Arrangement reference values
Weld points and cut lines for replacement of each panel
(2) Service manual - Body
Air bag removal and fitting, diagnosis
Removal and fitting of interior and exterior fittings
(3) Service manual - Chassis
Adjustment of suspension and wheel alignment
Appendices 6
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