NC-1
CHAPTER 1
Service Steering Components
Lesson: 1.16 Replace power steering pump
LEARNING GUIDE
Learning Steps
1.
Read the Information Sheet 1.16: on function of power
steering pump, construction, types of power steering
pumps, operation of power steering pump and replace
power steering pump.
Resources
Information Sheet 1.16
2.
Read and Perform Operation Sheet 1.16: on replacing
power steering pump
Operation Sheet 1.16
3.
Answer Self Check 1.16 on replacing power steering
pump
Sample Self Check 1.16
4.
Compare to Model Answer 1.16 on replace power steering
pump
Model Answer to Self Check 1.16
If finished, proceed to lesson 17
After completing the activities of this learning unit you should achieve the following:

Function of power steering pump

Construction of power steering pump

Types of power steering pump

Operation of power steering pump
INFORMATION SHEET 1.16
Function of power steering pump
In a modern power steering system, the pump provides power steering fluid under pressure to the steering gear box. When
the driver provides steering input by turning the steering wheel, the power steering control valve applies fluid pressure to one
side of a piston, which assists the driver in turning the wheel.
Construction of power steering pump:
The hydraulic power for the steering is provided by a rotaryvane pump. This pump is driven by the car's engine via a
belt and pulley. It contains a set of retractable vanes that spin
inside an oval chamber.
As the vanes spin, they pull hydraulic fluid from the return
line at low pressure and force it into the outlet at high
pressure. The amount of flow provided by the pump depends
on the car's engine speed. The pump must be designed to
provide adequate flow when the engine is idling. As a result,
the pump moves much more fluid than necessary when the
engine is running at faster speeds.
The pump contains a pressure-relief valve to make sure that
the pressure does not get too high, especially at high engine
speeds when so much fluid is being pumped.
Vane pump
components
1. The pump
housing contains the
entire pump
assembly except for
the fluid reservoir.
2. The
pump's rotor connects to the portion of the shaft located inside the
housing.
3. The pump's cam ring is a steel plate with a cam-shaped (or
eccentrically shaped) center hole.
4. The pump's pressure plate, constructed of flat, ground-steel, is
located against the sides of the cam ring.
5. The pump's flow control valve (a spool valve) reduces the
amount of fluid that the pump delivers to the steering gear assembly during
excessive pump output (such as during high-speed driving). The valve
therefore reduces fluid temperatures and conserves engine power.
Types of hydraulic power steering pump
1.
2.
3.
Roller type
Slipper type
Gear typ
Operation of power steering pump
The vane pump consists of a rotor, a cam ring, and
vanes. It contains a set of retractable vanes that spin
inside an oval chamber. When the rotor rotates, the
vane in each slot of the rotor is radically moved out by
centrifugal force and pressed against the cam ring. The
fluid from the suction port is confined in chambers
formed between two adjacent vanes and carried to the discharge port.
As the vanes spin, they pull hydraulic fluid from the return line at low pressure and force it into the outlet at high pressure.
The amount of flow provided by the pump depends on the car's engine speed. The pump must be designed to provide
adequate flow when the engine is idling. As a result, the pump moves much more fluid than necessary when the engine is
running at faster speeds
The pump contains a pressure-relief valve to make sure that the pressure does not get too high, especially at high engine
speeds when so much fluid is being pumped
OPERATION SHEET 1.16
PROCEDURE:
1.
Drain out the
power steering fluid from reservoir
OPERATION
TITLE:
Replace power steering pump
2.
Disconnect the pressure tube and suction hose Defective power steering pump
PURPOSE:
3. Loosen the drive belt adjusting bolt
CONDITIONS OR SITUATIONS FOR THE
OPERATION:
EQUIPMENT, TOOLS AND MATERIALS:
4.
5.
Remove the drive belt
Remove the pump pulley
6.
7.
Loosen the pump mounting bolts
Remove the pump
8.
Replace the new pump
9. Install new pump in reverse order of removal
10. Adjust the power steering drive belt tension
11. Refill the power steering fluid
Pump components worn out

Vehicle

Hand tools

Wedge

Steering fluid
 Power steering pump
12. Bleed the power steering system
PRECAUTIONS:

Ensuring that the power steering fluid is disposed in proper place
ASSESSMENT
CRITERIA:

Power steering drive belt tension is adjusted to the specification as per service manual

Power steering pump is replaced without damaging to the other components as per the
service manual

Air is completely removed from the power steering system

SAMPLE OF SELF CHECK 1.16
Self Check 1.16
SECTION A: Short Answer type question
1.
2.
3.
State the function of power steering pump.
List the types of steering pump.
List the components of power steering vane pump.
SECTION B: Multiple choice/matching questions
1.
Match the correct name given in column ‘B’ for the vane pump diagram given in column ‘A’.
Column ‘A’
a.
b.
c.
d.
e.
f.
g.
h.
i.
j.
SECTION C: Open ended type question
1.
2.
Explain the construction of power steering pump.
Explain the operation of power steering pump.
Column ‘B’
Pump cover
Rotor
Vanes
Pressure control valve
Drive shaft
From fluid reservoir
Pump housing
Spool valve
Pulley
To steering gear box

Model Answer 1.16
MODEL ANSWER TO A SELF-CHECK 1.16
SECTION A: Short Answer type question
1. In a modern power steering system, the pump provides power steering fluid under pressure to the steering gear
box. When the driver provides steering input by turning the steering wheel, the power steering control valve
applies fluid pressure to one side of a piston, which assists the driver in turning the wheel.
2. Types of steering pump
a. Roller type
b. Slipper type
c. Gear typ
3. Components of vane pump are;
1. Pump housing
2. Pump rotor
3. Cam ring
4. Pressure plate
5. Flow control valve
SECTION B: Multiple choice/matching questions
1. Pulley
2. Drive shaft
3. Pressure control valve
4. From fluid reservoir
5. To steering gear box
6. Pump cover
7. Rotor
8. Pump housing
SECTION C: Open ended type question
1. Construction of power steering pump:
The hydraulic power for the steering is provided by a rotary-vane pump. This pump is driven by the car's engine via a
belt and pulley. It contains a set of retractable vanes that spin inside an oval chamber. As the vanes spin, they pull
hydraulic fluid from the return line at low pressure and force it into the outlet at high pressure. The amount of flow
provided by the pump depends on the car's engine speed. The pump must be designed to provide adequate flow when
the engine is idling. As a result, the pump moves much more fluid than necessary when the engine is running at faster
speeds. The pump contains a pressure-relief valve to make sure that the pressure does not get too high, especially at
high engine speeds when so much fluid is being pumped.
2.
Operation of power steering pump
The vane pump consists of a rotor, a cam ring, and vanes. It contains a set of retractable vanes that spin inside an oval
chamber. When the rotor rotates, the vane in each slot of the rotor is radically moved out by centrifugal force and pressed
against the cam ring. The fluid from the suction port is confined in chambers formed between two adjacent vanes and carried
to the discharge port.
As the vanes spin, they pull hydraulic fluid from the return line at low pressure and force it into the outlet at high pressure.
The amount of flow provided by the pump depends on the car's engine speed. The pump must be designed to provide
adequate flow when the engine is idling. As a result, the pump moves much more fluid than necessary when the engine is
running at faster speeds
The pump contains a pressure-relief valve to make sure that the pressure does not get too high, especially at high engine
speeds when so much fluid is being pumped
Reference
(2013, 01 21). Retrieved from how a car works: www.howacarworks.com
Singh, D. (2007). Automobile Engineering Vol. 1. Delhi: Standard Publishers Distributors.
(how a car works, 2013)
(2013, 01 21). Retrieved from how a car works: www.howacarworks.com
CHAPTER 1
Service Steering Components
Lesson: 1.17 Replace electronic power steering assembly
LEARNING GUIDE
Learning Steps
Resources
1. Read the Information Sheet 1.17: on
construction of electronic power steering
assembly, operation of power steering pump Information Sheet 1.17
and replacing electronic power steering
assembly.
2. Read and Perform Operation Sheet 1.17:
Operation Sheet 1.17
3. Answer Self Check 1.17. on replace
electronic power steering assembly
Sample Self Check 1.17
4. Compare to Model Answer 1.17 on replace
Model Answer to Self Check 1.17
electronic power steering assembly
After completing the activities of this learning unit you should achieve the following:
 Construction of electronic power steering assembly
 Operation of electronic power steering assembly
INFORMATION SHEET 1.17
Construction of electronic power steering assembly:
In this type of steering system, steering sensor consist of tow sensors: “Torque senor” and
“Rotation sensor” ‘Torque sensor’ converts the steering torque input and its direction into
voltage signals. ‘Rotation sensor’ converts the rotation speed and direction into voltage
signals and is located on the input shaft of the steering gear box. The inputs from steering
sensor and the vehicle speed sponsor are sent to a microprocessor control unit where these are
compared with a preprogrammed force assist map. The control unit then sends out the
appropriate command signal to the current controller which supplies the appropriate current
to the electric motor which pushes the rack to the right or left depending on in which
direction the current flows. The amount of power assists increases with the increase in
current. There is a provision to protect the electric motor form being overloaded and also
from the voltage surges from a faulty alternator or charging problem.
Operation of electronic power steering assembly;
Power steering systems supplement the
torque that the driver applies to the
steering wheel. Traditional power
steering systems are hydraulic systems,
but electric power steering (EPS) is
becoming much more common. EPS
eliminates many hydraulic power steering
(HPS) components such as the pump,
hoses, fluid, drive belt, and pulley. For
this reason electric steering systems tend
to be smaller and lighter than hydraulic
systems.EPS systems have variable
power assist, which provides more
assistance as the speed of a vehicle
decreases and less assistance at higher
speeds. They do not require any
significant power to operate when no
steering assistance is required. For this
reason, they are more energy efficient
than hydraulic systems.
How the system works:


The EPS electronic control unit (ECU) calculates the assisting power needed
based on the torque being applied to the steering wheel by the driver, the
steering wheel position and the vehicle’s speed.
The EPS motor rotates a steering gear with an applied force that reduces the
torque required from the driver.
There are four forms of EPS, based on the position of the assist motor. They are;
1.
2.
3.
4.
Column assist type (C-EPS)
Pinion assist type (P-EPS)
Direct drive type (D-EPS)
Rack assist type (R-EPS)
OPERATION SHEET 1.17
OPERATION TITLE:
PURPOSE:
CONDITIONS OR SITUATIONS FOR
THE OPERATION:
EQUIPMENT, TOOLS AND
MATERIALS:
Replace electronic power steering assembly
Defective or worn out electronic steering components
Defective or worn out electronic steering components
 Vehicle
 Hand tools
 Wedge
 Electronic Power steering assembly
PROCEDURE:
1. Disconnect the Negative battery cable
2. Remove the steering wheel
3. Disconnect the electric connection from the motor
4. Remove the Steering column assembly
5. Disconnect the intermediate shaft from pinion shaft
6. Jack up the vehicle
7. Remove the wheels
8. Remove the tie rod end ball joint from knuckle arm
9. Remove the gear box mounting brackets
10. Remove the rack and pinion steering assembly
11. Replace the electronic power steering assembly in the
reverse order of removal
PRECAUTIONS:
 Ensuring that old electronic power steering assembly is disposed in
the scrap yard
ASSESSMENT
 Electronic power steering is replaced as per standard procedures
CRITERIA:
 Related electrical connections are connected securely

SAMPLE OF SELF CHECK 1.17
Self Check 1.17
SECTION A: Short Answer type question
1.
2.
3.
4.
Name the types of sensors used in electronic power steering.
State the function of torque sensor.
State the function rotation sensor/steering angle sensor.
What does EPS stand for?
SECTION B: Multiple choice/matching questions
1. Match the correct name given in column ‘B’ for the exploited diagram of electronic
power steering assembly given in column ‘A’.
Column ‘A’
Column ‘B’
1. Electronic torque sensor
2. Rack screw
3. Motor
4. Rack and pinion
5. Vehicle speed sensor
6. Electric power
7. Input torque
8. Rotation sensor
9. Belt and ball nut
10. Computer
11. Steering gear box
SECTION C: Open ended type question
1. Explain briefly the operation of electronic power steering assembly.

Model Answer 1.17
MODEL ANSWER TO A SELF-CHECK 1.17
SECTION A: Short Answer type question
1. Torque sensor and rotation sensor
2. Torque sensor converts the steering torque input and its direction into voltage signals.
3. Rotation sensor converts the rotation speed and direction into voltage signals and is
located on the input shaft of the steering gear box.
4. Electric power steering
SECTION B: Multiple choice/matching questions
1. Electronic power steering assembly
1. Input torque
2. Rack and pinion
3. Torque sensor
4. Vehicle speed sensor
5. Electric power
6. Computer
7. Motor
8. Rack screw
9. Belt and ball nut
SECTION C: Open ended type question
1. Operation of electronic power steering
 The EPS electronic control unit (ECU) calculates the assisting power
needed based on the torque being applied to the steering wheel by the
driver, the steering wheel position and the vehicle’s speed.
 The EPS motor rotates a steering gear with an applied force that reduces
the torque required from the driver.
Reference
(2013, 01 21). Retrieved from how a car works: www.howacarworks.com
http://www.cvel.clemson.edu/auto/. (2014, 01 22). [email protected] Retrieved from
www.cvel.clemson.edu/auto/systems/ep_steering.html
Singh, D. (2007). Automobile Engineering Vol. 1. Delhi: Standard Publishers Distributors.
(2013, 01 21). Retrieved from how a car works: www.howacarworks.com
http://www.cvel.clemson.edu/auto/. (2014, 01 22). [email protected] Retrieved from
www.cvel.clemson.edu/auto/systems/ep_steering.html
Singh, D. (2007). Automobile Engineering Vol. 1. Delhi: Standard Publishers Distributors.
CHAPTER 3
Adjust brake pedal free play
Lesson 3.1: Adjust brake pedal free play
LEARNING GUIDE
Learning Steps
Resources
1. Read the Information Sheet 3.1: on purpose
of brake pedal free play, purpose pedal
Information Sheet 3.1
height, purpose of reserve distance and
adjust pedal free play.
2. Read and Perform Operation Sheet 3.1:
on adjust pedal free play
Operation Sheet 3.1:
3. Read and Perform Job Sheet 3.1: on
adjust pedal free play
Job Sheet 3.1
4. Answer Self Check 3.1: on adjust pedal
free play
Sample Self Check 3.1
5. Compare to Model Answer 3.1: on adjust
Model Answer to Self Check 3.1
pedal free play
If finished, proceed to lesson 3.2
After completing the activities of this learning unit you should achieve the following:



Purpose of brake pedal free play
Purpose of pedal height
Purpose of reserve distance
3.1.1 Purpose of brake pedal free play





Is to trap a small amount of pressure in the brake
system.
To prevent brake drag and overheating.
To determine measurement of how far the pedal
moves before the master cylinder first begins to
apply.
To ensure that there is less play before the brakes start grabbing.
Improves pedal feel and helps to get rid of that that there is a bunch of
free play before the brakes actually start working.
3.1.2 Purpose of pedal height


To determine pedal in its original position
To ensure that pedal bushings, return springs, or master
cylinder push rod are working properly.
3.1.3 Purpose of reserve distance




To determine measurement from the floorboard of the vehicle to
the TOP of the brake pedal when the brakes are applied.
Reserve distance determines all braking systems in order to keep
the Vent Port open inside the master cylinder.
To ensure that there is no air in the system
To ensure that the automatic brake adjusters may not be working.
OPERATION SHEET 3.1
OPERATION TITLE:
Adjust brake pedal free play
PURPOSE:
Overhaul master cylinder or power brake booster
CONDITIONS OR SITUATIONS
FOR THE OPERATION:
When the following symptoms are observed:
EQUIPMENT, TOOLS AND
MATERIALS:







Too much play in the pedal
Leakages from master cylinder push rod
Over heating of brake
Vehicle
Wheel wedge
Hand tools
Measuring Tape/ruler
PROCEDURE:
1. Depress the brake pedal several times until there
is no more vacuum left in the booster.
2. Depress the pedal by hand until the resistance is
felt.
3. Measure the pedal’s free play between the
position in the previous step and pedal’s released
position.
4. Adjust the pedal free play by turning the push
rod.
5. Measure the pedal free play, pedal height and
reserve distance.
6. Measure the clearance of brake light switch.
7. Adjust the clearance of brake light switch if
required
PRECAUTIONS:
 Ensuring parking brake is engaged
ASSESSMENT CRITERIA:
 Brake pedal free play is adjusted to the specification as per the service manual
JOB SHEET 3.1
JOB TITLE:
Adjust brake pedal free play
READING:
Performance guide, service manual, information sheet and operation
sheet.
Adjust brake pedal free play
OBJECTIVE:
MATERIALS
REQUIRED:
TOOLS &
EQUIPMENT
REQUIRED:

PROCEDURE:
ASSESSMENT
CRITERIA:
Trainer will use the following criteria during assessment:


Self
Check 3.1
SAMPLE OF SELF CHECK 3.1
SECTION A: Short Answer type question
1. State the purpose of pedal free play.
2. State the purpose of brake pedal height.
3. State the purpose of brake pedal reserve distance.

MODEL ANSWER TO A SELF-CHECK 3.1
Model Answer 3.1
SECTION A: Short Answer type question
1.
a. Is to trap a small amount of pressure in the brake system.
b. To prevent brake drag and overheating.
c. To determine measurement of how far the pedal moves before the master
cylinder first begins to apply.
d. To ensure that there is less play before the brakes start grabbing.
e. Improves pedal feel and helps to get rid of that that there is a bunch of free
play before the brakes actually start working.
2.
a. To determine pedal in its original position
b. To ensure that pedal bushings, return springs, or master cylinder push rod are
working properly.
3.
a. To determine measurement from the floorboard of the vehicle to the TOP of
the brake pedal when the brakes are applied.
b. Reserve distance determines all braking systems in order to keep the Vent Port
open inside the master cylinder.
c. To ensure that there is no air in the system
d. To ensure that the automatic brake adjusters may not be working.
Bibliography
(Automotive, 2013)
Anglin, W. H. (2007). Automotive Mechanics. New Delhi: Tata McGraw-Hill.
Singh, D. K. (2009). Automobile Engineering Vol 1. Delhi: Standard Publishers Distributors.
(Kim)
CHAPTER 3
Adjust brake pedal free play
Lesson 3.1: Adjust brake pedal free play
LEARNING GUIDE
Learning Steps
Resources
1. Read the Information Sheet 3.1: on purpose
of brake pedal free play, purpose pedal
Information Sheet 3.1
height, purpose of reserve distance and
adjust pedal free play.
2. Read and Perform Operation Sheet 3.1:
on adjust pedal free play
Operation Sheet 3.1:
3. Read and Perform Job Sheet 3.1: on
adjust pedal free play
Job Sheet 3.1
4. Answer Self Check 3.1: on adjust pedal
free play
Sample Self Check 3.1
5. Compare to Model Answer 3.1: on adjust
Model Answer to Self Check 3.1
pedal free play
If finished, proceed to lesson 3.2
After completing the activities of this learning unit you should achieve the following:



Purpose of brake pedal free play
Purpose of pedal height
Purpose of reserve distance
3.1.1 Purpose of brake pedal free play





Is to trap a small amount of pressure in the brake
system.
To prevent brake drag and overheating.
To determine measurement of how far the pedal
moves before the master cylinder first begins to
apply.
To ensure that there is less play before the brakes start grabbing.
Improves pedal feel and helps to get rid of that that there is a bunch of
free play before the brakes actually start working.
3.1.2 Purpose of pedal height


To determine pedal in its original position
To ensure that pedal bushings, return springs, or master
cylinder push rod are working properly.
3.1.3 Purpose of reserve distance




To determine measurement from the floorboard of the vehicle to
the TOP of the brake pedal when the brakes are applied.
Reserve distance determines all braking systems in order to keep
the Vent Port open inside the master cylinder.
To ensure that there is no air in the system
To ensure that the automatic brake adjusters may not be working.
OPERATION SHEET 3.1
OPERATION TITLE:
Adjust brake pedal free play
PURPOSE:
Overhaul master cylinder or power brake booster
CONDITIONS OR SITUATIONS
FOR THE OPERATION:
When the following symptoms are observed:
EQUIPMENT, TOOLS AND
MATERIALS:







Too much play in the pedal
Leakages from master cylinder push rod
Over heating of brake
Vehicle
Wheel wedge
Hand tools
Measuring Tape/ruler
PROCEDURE:
1. Depress the brake pedal several times until there
is no more vacuum left in the booster.
2. Depress the pedal by hand until the resistance is
felt.
3. Measure the pedal’s free play between the
position in the previous step and pedal’s released
position.
4. Adjust the pedal free play by turning the push
rod.
5. Measure the pedal free play, pedal height and
reserve distance.
6. Measure the clearance of brake light switch.
7. Adjust the clearance of brake light switch if
required
PRECAUTIONS:
 Ensuring parking brake is engaged
ASSESSMENT CRITERIA:
 Brake pedal free play is adjusted to the specification as per the service manual
JOB SHEET 3.1
JOB TITLE:
Adjust brake pedal free play
READING:
Performance guide, service manual, information sheet and operation
sheet.
Adjust brake pedal free play
OBJECTIVE:
MATERIALS
REQUIRED:
TOOLS &
EQUIPMENT
REQUIRED:

PROCEDURE:
ASSESSMENT
CRITERIA:
Trainer will use the following criteria during assessment:


Self
Check 3.1
SAMPLE OF SELF CHECK 3.1
SECTION A: Short Answer type question
1. State the purpose of pedal free play.
2. State the purpose of brake pedal height.
3. State the purpose of brake pedal reserve distance.

MODEL ANSWER TO A SELF-CHECK 3.1
Model Answer 3.1
SECTION A: Short Answer type question
1.
a. Is to trap a small amount of pressure in the brake system.
b. To prevent brake drag and overheating.
c. To determine measurement of how far the pedal moves before the master
cylinder first begins to apply.
d. To ensure that there is less play before the brakes start grabbing.
e. Improves pedal feel and helps to get rid of that that there is a bunch of free
play before the brakes actually start working.
2.
a. To determine pedal in its original position
b. To ensure that pedal bushings, return springs, or master cylinder push rod are
working properly.
3.
a. To determine measurement from the floorboard of the vehicle to the TOP of
the brake pedal when the brakes are applied.
b. Reserve distance determines all braking systems in order to keep the Vent Port
open inside the master cylinder.
c. To ensure that there is no air in the system
d. To ensure that the automatic brake adjusters may not be working.
Bibliography
(Automotive, 2013)
Anglin, W. H. (2007). Automotive Mechanics. New Delhi: Tata McGraw-Hill.
Singh, D. K. (2009). Automobile Engineering Vol 1. Delhi: Standard Publishers Distributors.
(Kim)
CHAPTER 3
Perform wheel alignment
Lesson 3.3: Adjust canter and camber angle
LEARNING GUIDE
Learning Steps
 Read the Information Sheet 3.3: on definition
of camber and caster, purpose of caster and
camber, effects of caster and camber, and
procedures of adjusting caster and camber
angle
Resources
Information Sheet 3.3
Read and Perform Operation Sheet 3.3: on Adjust Operation Sheet 3.3
canter and camber angle
Read and Perform Job Sheet 3.3: On
perform wheel alignment
Answer Self Check 3.3 on adjust caster and
camber angle
Compare to Model Answer 3.3 on adjust caster
Job Sheet 3.3
Sample Self Check 3.3
Model Answer to Self Check3.13
and camber angle
If finished, proceed to lesson 3.4
After completing the activities of this learning unit you should achieve the following:




Define camber and caster angle
State the purpose of caster and camber angle
List the effects of caster and camber angle
Perform adjustment of caster and camber angle
INFORMATION SHEET 3.3
3.3.1 Definition of caster and camber angle
Caster angle:
The kingpin or the steering axis is tilled forwards or backward from the
vertical is known as caster angle. The backward tilt from the vertical is
known as positive caster and the forward tilt as negative caster. The caster
measured in degrees is kept between 2° and 7°. Increased amount of caster
and play in steering linkage leads to excessive front wheel
wobble.
Positive caster tends the wheel to toe-in while negative caster
causes the wheel to toe-out. In case caster angle on both the wheel is same, both
shall ‘toe-in’ equally and be balanced. If caster on one wheel is greater, the
vehicle will pull to the side of the wheel having lesser caster angle.
Too much positive caster on wheels causes wheel ‘shimmy’ and hard steering.
Low value of caster causes wheel wander. Vehicle having power steering must keep more
positive caster angle so that the front wheels may return after cornering. All though greater
positive caster provides greater stability, steering becomes hard. Vehicle with manual steering
have lesser caster reduce steering effort.
Camber angle:
The tilting in or out of the front wheels from the vertical when viewed from
the front of the vehicle is known as camber angle. If the top of the wheel tilts
out, it has “positive” camber. If the top of the wheel tilts in, it has “negative
"camber. During the manufacturing stage, a small positive camber is given to
the front’s wheels (generally less than 3°) So that the negative camber effects
due to bearing clearances, suspension deflections, axle deflections and dynamic
operating loads are taken care of.
The front wheels become nearly vertical resulting in zero camber angles and
these start rolling along the road. Excessive positive camber wears the outer
tread section of the tires and shoulder.
Negative camber is given to rear wheels of rear drive vehicles. If it is too negative, there will
be excessive wear of inner shoulder and tread section when vehicle is over loaded.
The camber angle is kept equal on both the front wheels so that the tire wear due to the ‘cone
effect’ is balanced. If the camber angle is unequal in both the wheels, the vehicle shall roll in
the direction of the wheel having greater camber, this affects directional stability.
3.3.2. Purpose of caster and camber angle




The steering system must ensure handling, good steering stability and recovery after
turns.
However, for the steering system to do their job properly, the front wheel must be
kept correctly aligned.
To reduce the dynamic stress and wear of each components part by properly setting
steering mechanism, and toe angle which moves in very complicated manner.
Front wheel alignment consists of adjustment of steering angles and dimensions of the
front wheel, after installation to the body structure which must be kept at accurate
value
3.3.3 Effects of caster and camber angle
Effects of caster angle
1.
2.
3.
4.
5.
Increase effectiveness in ensuring straight-ahead driving stability
Good wheel recovery after turning
Increase trial as well as the force that returns the steering wheel to neutral position
Increases the steering effort.
Provide lighter steering resistance
Effects of camber angle
1.
2.
3.
4.
5.
Emphasize the straight-ahead stability of the vehicle.
Reduce ground camber of the vehicle during rolling.
Improve vehicle cornering performance.
Assist in reducing the tendency of front wheel to toe-out.
Reduce direct road shock to the steering system.
OPERATION SHEET 3.3
OPERATION TITLE:
Adjust caster and camber angle
PURPOSE:
Sometimes tire tends to wear due to unequal pressure,
defective steering components or worn out kingpin
bearing. So if we do not perform adjustment of caster
and camber angle, the tire tends to wear unevenly within
short period of time and driving comforts become poor.
CONDITIONS OR SITUATIONS
FOR THE OPERATION:
When the following symptoms are observed:





Uneven tire wear
Car wader
Unwanted noise
Short tire life
Hard steering
EQUIPMENT, TOOLS AND
MATERIALS:





Vehicle
Hand tools
Wheel wedge
Caster and camber gauge
SST
PROCEDURE:
1. Park the vehicle on the ramp/lift.
2. Wedge the wheels.
3. Perform pre-alignment.
4. Position the steering wheel straight
ahead.
5. Lock the steering wheel with SST.
6. Install camber and caster gauge.
7. Loosen the front adjusting cam nut.
8. Adjust camber and caster by adjusting
cam bolt to the center value of the
gauge.
9. Tighten the adjusting cam nut with
specific torque
10. Remove the camber and caster gauge.
11. Repeat the steps from 6 to 9 for the next
wheel.
PRECAUTIONS:
 Ensuring vehicle is parked safely
 Ensuring that the steering wheel is not disturbed while performing alignment.
ASSESSMENT CRITERIA:
 All steps are followed in correct sequence.
 Safety precautions are followed.
 Camber and caster angle is adjusted as per standard procedures and specification
JOB SHEET 3.3
JOB TITLE:
Perform wheel alignment
READING:
Performance guide, service manual, information sheet and operation
sheet.
Perform wheel alignment as per the standard procedure
OBJECTIVE:
MATERIALS
REQUIRED:
TOOLS &
EQUIPMENT
REQUIRED:
PROCEDURE:

Marker/ chalk







Vehicle
Hand tools
Wheel wedge
Caster and camber gauge
SST
Measure tape/ steel ruler
Steering wheel lock (SST)








Park the vehicle on level ground.
Perform pre-alignment.
Position the steering wheel straight ahead.
Lock the steering wheel by SST
Perform toe-in adjustment.
Install camber and caster gauge.
Perform caster camber adjustment.
Adjust camber and caster by adjusting cam bolt to the center
value of the gauge.
Remove the caster camber gauge.
Tests drive the vehicle.


ASSESSMENT
CRITERIA:
Trainer will use the following criteria during assessment:






All steps are followed in correct sequence.
Safety precautions are followed.
Tighten the adjusting cam nut with specific torque
Toe-in is adjusted as per specification given in service manual
The locked steering wheel is not disturbed
Camber and caster angle is adjusted as per standard procedures
and specification

SAMPLE OF SELF CHECK 3.3
Self Check 3.3
SECTION A: Short Answer type question
1. Define caster angle.
2. Define camber angle.
SECTION B: Multiple Choice question/objective type questions
1. The backward tilt from the vertical is known as _____________.
A. Negative caster
B. Negative camber
C. Positive caster
D. Positive camber
2. The forward tilt from the vertical is known as _____________.
A. Negative camber
B. Positive camber
C. Positive caster
D. Negative caster
3. If the top of the wheel tilts out, it has ___________.
A. Positive camber
B. Negative caster
C. Positive caster
D. Negative caster
4. If the top of the wheel tilts in, it has ______________.
A. Negative caster
B. Negative camber
C. Positive caster
D. Positive camber
SECTION C: True/false or matching type question
1. Excessive positive camber wears the outer tread section of the tires and shoulder. T/F
2. Increased amount of caster and play in steering linkage leads to excessive front wheel
wobble. T/F
3. The caster measured in degrees is kept between 2° and 6°. T/F
4. During the manufacturing stage, a small positive camber is given to the front’s wheel,
generally less than 3°. T/F
SECTION D: Explanation type/open ended type question
1. State the purposes of caster and camber angle.
2. List all the effects of caster and camber angle.

Model Answer 3.3
MODEL ANSWER TO A SELF-CHECK 3.3
SECTION A: Short Answer type question
1. The kingpin or the steering axis is tilled forwards or backward from the vertical is
known as caster angle.
2. The tilting in or out of the front wheels from the vertical when viewed from the front
of the vehicle is known as camber angle.
SECTION B: Multiple Choice question/objective type questions
1.
2.
3.
4.
C
D
A
B
SECTION C: True/false or matching type question
1.
2.
3.
4.
T
T
F
T
SECTION D: Explanation type/open ended type question
1. Purpose of caster and camber angle
 The steering system must ensure handling, good steering stability and recovery after
turns.
 However, for the steering system to do their job properly, the front wheel must be
kept correctly aligned.
 To reduce the dynamic stress and wear of each components part by properly setting
steering mechanism, and toe angle which moves in very complicated manner.
 Front wheel alignment consists of adjustment of steering angles and dimensions of the
front wheel, after installation to the body structure which must be kept at accurate
value
2. Effects of caster angle
1. Increase effectiveness in ensuring straight-ahead driving stability
2. Good wheel recovery after turning
3. Increase trial as well as the force that returns the steering wheel to neutral position
4. Increases the steering effort.
5. Provide lighter steering resistance
Effects of camber angle
1.
2.
3.
4.
5.
Emphasize the straight-ahead stability of the vehicle.
Reduce ground camber of the vehicle during rolling.
Improve vehicle cornering performance.
Assist in reducing the tendency of front wheel to toe-out.
Reduce direct road shock to the steering system.
Reference
angelin, C. (1985). Automotive Mechanics. New Delhi: Tata McGraw-Hill.
Anglin, W. H. (2007). Automotive Mechanics. New Delhi: Tata McGraw-Hill.
Anglin, W. H. (2009). Automotive Mechanics. New Delhi: tata Mcgraw Hill Education.
Corporation, M. M. (2002). Automatic Transmission. Mitsubishi Motor Cor[poration.
Corporation, T. M. (2002). Fundamentals of Serviicing Vol. 2. Toyota city: Toyota Motor
Corporation.
James D, H. (1991). Singh, D. K. (2009). Automobile Engineering Vol 1. Delhi: Standard
Publishers Distributors.
Lesson 21: Parking brake
LEARNING GUIDE
Learning Steps
Resources
1. Read the Information Sheet 21: on
function of parking brake
Information Sheet 21
2. Read and Perform Operation Sheet 21: on
adjusting parking brake
Operation Sheet 21
3. Answer Self Check 21
Sample Self Check 21
4. Compare to Model Answer 21
Model Answer to Self Check 21
If finished, proceed to lesson 22
After completing the activities of this learning unit you should achieve the following:
 State the function of parking brake
 State the types of parking rake
INFORMATION SHEET 21
21.1
Function of parking brake
The function of parking brake is to prevent the vehicle from rolling away when it has been
sopped or parked, even if the road surface is slopping and it is also used as an auxiliary
service brake, in case the main service brake shoe failed
21.2
Types of parking rake
The types of parking brake are
a.
OPERATION SHEET 21
OPERATION TITLE:
Adjust parking brake
PURPOSE:
To have effectiveness in stopping the vehicle in
downhill while applying parking brake
CONDITIONS OR SITUATIONS
When there is improper functioning of parking brake
FOR THE OPERATION:
EQUIPMENT, TOOLS AND
Vehicle , Hand tools , Lift/Ramp, Wheel wedge
MATERIALS:
1.
2.
3.
4.
5.
6.
7.
8.
Park the vehicle on the lift/ramp/ground
Wedge the wheel
Adjust the rear brake shoe clearance before adjusting the parking brake
Check the parking brake level travel by pulling the parking lever all the way up
Count the number of clicks
Tighten the adjusting nut until the travel is correct
Tighten the adjusting lock nut
Check that the rear brakes are not dragging after adjusting parking brake
PRECAUTIONS:

Appropriate use of PPE
ASSESSMENT


Parking brake is adjusted as per standard procedures
Parking brake holds the vehicle when parked on the slope
CRITERIA:

SAMPLE OF SELF CHECK 1.14
Self Check 21
SECTION A: Short Answer type question
1. State the function of parking brake
2. What are the types of parking brake

MODEL ANSWER TO A SELF-CHECK 21
Model Answer 21
Section A
1. The function of parking brake is to prevent the vehicle from rolling away when it has
been sopped or parked, even if the road surface is slopping and it is also used as an
auxiliary service brake, in case the main service brake shoe failed
2. The types of parking brake are
a. Sick type
b. Centre lever type
c. Pedal type
Bibliography
http://www.autoshop101.com/forms/brake06.pdf. (2014, 01 22). parking brake. Retrieved
from http://www.autoshop101.com/forms/brake06.pdf:
http://www.autoshop101.com/forms/brake06.pdf
Lesson 21: Parking brake
LEARNING GUIDE
Learning Steps
Resources
1. Read the Information Sheet 21: on
function of parking brake
Information Sheet 21
2. Read and Perform Operation Sheet 21: on
adjusting parking brake
Operation Sheet 21
3. Answer Self Check 21
Sample Self Check 21
4. Compare to Model Answer 21
Model Answer to Self Check 21
If finished, proceed to lesson 22
After completing the activities of this learning unit you should achieve the following:
 State the function of parking brake
 State the types of parking rake
INFORMATION SHEET 21
21.1
Function of parking brake
The function of parking brake is to prevent the vehicle from rolling away when it has been
sopped or parked, even if the road surface is slopping and it is also used as an auxiliary
service brake, in case the main service brake shoe failed
21.2
Types of parking rake
The types of parking brake are
a.
OPERATION SHEET 21
OPERATION TITLE:
Adjust parking brake
PURPOSE:
To have effectiveness in stopping the vehicle in
downhill while applying parking brake
CONDITIONS OR SITUATIONS
When there is improper functioning of parking brake
FOR THE OPERATION:
EQUIPMENT, TOOLS AND
Vehicle , Hand tools , Lift/Ramp, Wheel wedge
MATERIALS:
1.
2.
3.
4.
5.
6.
7.
8.
Park the vehicle on the lift/ramp/ground
Wedge the wheel
Adjust the rear brake shoe clearance before adjusting the parking brake
Check the parking brake level travel by pulling the parking lever all the way up
Count the number of clicks
Tighten the adjusting nut until the travel is correct
Tighten the adjusting lock nut
Check that the rear brakes are not dragging after adjusting parking brake
PRECAUTIONS:

Appropriate use of PPE
ASSESSMENT


Parking brake is adjusted as per standard procedures
Parking brake holds the vehicle when parked on the slope
CRITERIA:

SAMPLE OF SELF CHECK 1.14
Self Check 21
SECTION A: Short Answer type question
1. State the function of parking brake
2. What are the types of parking brake

MODEL ANSWER TO A SELF-CHECK 21
Model Answer 21
Section A
1. The function of parking brake is to prevent the vehicle from rolling away when it has
been sopped or parked, even if the road surface is slopping and it is also used as an
auxiliary service brake, in case the main service brake shoe failed
2. The types of parking brake are
a. Sick type
b. Centre lever type
c. Pedal type
Bibliography
http://www.autoshop101.com/forms/brake06.pdf. (2014, 01 22). parking brake. Retrieved
from http://www.autoshop101.com/forms/brake06.pdf:
http://www.autoshop101.com/forms/brake06.pdf
CHAPTER 8
Perform wheel alignment
Lesson 3.2: Adjust Toe-in
LEARNING GUIDE
Learning Steps
Resources
1. Read the Information Sheet3.2: on
definition of toe-in, purpose of toe angle, Information Sheet3.2
turning radius and adjust toe-in.
2. Read and Perform skill sheet 3.2: Read and
Skill sheet 3.2
interpret manuals
3. Read and Perform Operation Sheet3.2:
Adjust Toe-in
Operation Sheet 3.2
4. Answer Self Check 3.2 on adjust toe-in
Sample Self Check 3.2
5. Compare to Model Answer 3.2 on adjust
Model Answer to Self Check3.2
toe-in
If finished, proceed to lesson 3.3
After completing the activities of this learning unit you should achieve the following:





State definition of toe- in and toe-out
Explain purpose of toe angle
Explain the effects of toe angle
Explain the turning radius
Adjusting toe-in
INFORMATION SHEET 3.2
Steering geometry:
The term "steering geometry” (also known as "front-end geometry") refers to the angular
relationship between suspension and steering parts, front wheels, and the road surface.
Because alignment deals with angles and affects steering, the method of describing alignment
measurements is called steering geometry. Traditionally, there are five steering geometry
angles: Camber, Caster, Toe angle, kingpin inclination (SAI).
 Toe-in
 Toe-out and
 Camber angle
 Caster angle
 Kingpin inclination
3.2.1 Definition of Toe-in and Toe-out
Toe-in:
If the front of the wheels point inward toward the car so that the fronts of the
wheels are closer together than the back of the wheels then the wheels are in the
toe-in position. Toe-in is generally measured in millimeter, i.e., 1/8-1/4 inch. (3.186.35 mm),
Incorrect toe-in causes:
 Tire slip
 Tire wear on outside of the tread
 Tire scrub and
 Poor steering stability
Toe-out:
If the front of the wheels point away from the car so that the fronts of the
wheels are further apart than the back of the wheels then the wheels are in
the toe-out position.
Toe-out is provided by keeping proper relation between the steering
knuckle arms, tie rods and drop arm. These linkages are arranged such that
the inner wheel left or right, toe-out more than the outer wheel when taking
a curve.
3.2.2 Purpose of Toe-angle
i)
ii)
iii)
iv)
v)
vi)
Good directional stability
Steering ease
Minimum tire wear
Reversibility of steering gear and
Good riding qualities of the vehicle
Better Gas Mileage/fuel consumption
Kingpin inclination (KPI):
This angle is also known as steering axis inclination. The king-pin inclination or
(steering axis inclination) is the angle between the vertical line and centre of the
kingpin or steering axle, when viewed from the front of the vehicle.
The king-pin inclination is absolutely necessary due to the following:
1. It helps the car to have steering stability
2. It makes the operation of the steering quite easy particularly
when the vehicle is stationary.
3. It helps in reducing the tire wear on the tire.
3.2.3: Turning radius
If the right and left front wheels were both
to turn by exactly the same amount (that
is, if the right and left steering angles were
the same), they would have same turning
radius (r1 = r2), but each wheel would turn
around a different center (O1 and O2).
Smooth turning would therefore be
impossible due to side-slipping of the tires.
To prevent this, the knuckle arms and tie
rods are so arranged as to cause the wheels
to toe-out slightly greater angle than the outer wheel so that the centers around
which they turn will coincide but the turning radii will be different ( r1= r2 ).
SKILL SHEET 3.2
SKILL TITLE:
EQUIPMENT, TOOLS AND
MATERIALS:
Read and interpret manual
Service manual
PROCEDURE:
1. Identify the model of vehicle
2. Collect the appropriate manual as per the vehicle model
3. Select the correct specification chart
4. Select the value of toe-in and toe-out as per the specification given in manual
5. Interpret the specific value to apply in a given vehicle.
OPERATION SHEET 3.2
OPERATION TITLE:
Adjust Toe-in
PURPOSE:
Sometimes tire tends to wear due to unequal pressure,
defective linkages or worn out kingpin bearing and
faulty steering components. So if we do not perform toein adjustment, then the tire tends to wear unevenly
within short period of time.
CONDITIONS OR SITUATIONS
FOR THE OPERATION:
When the following symptoms are observed:





Uneven tire wear
Short tire life
Defective steering linkages
Hard steering
Steering dragging to one side
EQUIPMENT, TOOLS AND
MATERIALS:




Measure tape/ steel ruler
Marker/ chalk
Steering wheel lock (SST)
Hand tools
PROCEDURE:
1. Position the steering wheel straight ahead
2. Lock the steering wheel by SST
3. Measure the radius of both tires
4. Mark the centre of both front tire tread
5. Mark the centre of both rear of front tire tread
“B”
6. Measure the distance between centre of front
tires
7. Note the reading
8. Measure the distance between centre of front
rear tread “A”
9. Note the reading
10. Calculate the difference (B-A)
11. Adjust Toe-in (Repeat step 5-9 until required
value is obtained.
PRECAUTIONS:
 Ensuring appropriate use of PPE
 Ensuring the tie rod is tightened after adjustment
ASSESSMENT CRITERIA:
 All steps are followed in correct sequence.
 Safety precautions are followed.
 Toe-in is adjusted as per specification given in service manual
 The steering wheel locked straight ahead position

Self
Check 11.1
SAMPLE OF SELF CHECK 11.1
SECTION A: Short Answer type question
1.
2.
3.
4.
Define steering Geometry.
List the types of steering angle.
List the causes of incorrect toe angle.
List the requirements of kingpin inclination (KPI).
SECTION B: Multiple Choice question/objective type questions
1. If the front of the wheels point away from the car so that the fronts of the wheels are
further apart than the back of the wheels then the wheels are in the _______ position.
A. Toe-in
B. Camber
C. caster
D. Toe-out
2. If the front of the wheels point inward toward the car so that the fronts of the wheels
are closer together than the back of the wheels then the wheels are in the _______
position.
A. Toe-in
B. Camber
C. caster
D. Toe-out
SECTION D: Explanation type/open ended type question
1. Explain the construction of turning radius.
2. State the purpose of toe angle

Model Answer 3.2
MODEL ANSWER TO A SELF-CHECK 3.2
SECTION A: Short Answer type question
Ans 1: The term "steering geometry” (also known as "front-end geometry") refers to the
angular relationship between suspension and steering parts, front wheels, and the road
surface.
Ans 2:





Toe-in
Toe-out and
Camber angle
Caster angle
Kingpin inclination
Ans 3:




Tire slip
Tire wear on outside of the tread
Tire scrub and
Poor steering stability
Ans 4:



It helps the car to have steering stability
It makes the operation of the steering quite easy particularly when the vehicle is
stationary.
It helps in reducing the tire wear on the tire.
SECTION B: Multiple Choice question/objective type questions
Ans 1: D
Ans 2: A
SECTION C: Explanation type/open ended type question
Ans 1: Turning radius
If the right and left front wheels were both to turn by
exactly the same amount (that is, if the right and left
steering angles were the same), they would have
same turning radius (r1 = r2), but each wheel would
turn around a different center (O1 and O2). Smooth
turning would therefore be impossible due to sideslipping of the tires.
To prevent this, the knuckle arms and tie rods are so arranged as to cause the wheels to toe-out
slightly greater angle than the outer wheel so that the centers around which they turn will coincide but
the turning radii will be different ( r1= r2 ).
Ans 2: Purpose of Toe-angle
i)
ii)
iii)
iv)
v)
vi)
Good directional stability
Steering ease
Minimum tire wear
Reversibility of steering gear and
Good riding qualities of the vehicle
Better Gas Mileage/fuel consumption
Bibliography
Anglin, W. H. (2007). Automotive Mechanics. New Delhi: Tata McGraw-Hill.
Anglin, W. H. (2009). Automotive Mechanics. New Delhi: tata Mcgraw Hill Education.
Corporation, M. M. (2002). Automatic Transmission. Mitsubishi Motor Cor[poration.
Max Bohner et.al. (1989). Wuppertal: GTZ.
Ontario, Q. P. (2005). CooperatParrott, P. (2000). Singh, D. K. (2009). Automobile
Engineering Vol 1. Delhi: Standard Publishers Distributors.
Sweeney, T. (2002). Teaching strategies to improve learning and comprehension. RMC
Research Corporation.
www.autocorner.ca. (2013). Retrieved from www.autocorner.ca
Lesson 4.2: Adjust wheel bearing pre load
OPERATION SHEET 4.2
OPERATION TITLE:
PURPOSE:
CONDITIONS OR SITUATIONS FOR
THE OPERATION:
EQUIPMENT, TOOLS AND
MATERIALS:
Adjust wheel bearing pre load
 To precisely determine the position of a shaft
in radial and axial directions, and to increase
its rotating precision at the same time.
 To increase the bearing rigidity
 To prevent vibration or abnormal noise
generated by trembling shaft.
 To restrict the sliding revolution and sliding
rotation of rolling element.
 For exact position control of rolling element
against the rings.
When a new bearing is installed or after
overhauling wheel hub assembly
Torque meter , Marking cloth , Tray , SST, Sets of
mechanic hand tools , Spring tension gauge and pre
load gauge , Lock nut, check nut, Lock washer
1. Collect the required tools and materials
2. Torque the bearing check/adjusting nut by
SST
3. Turn the hub several times to free the
bearing
4. Tighten the bearing check/adjusting nut
5. Loosen the bearing check/adjusting nut
until it can be rotate by hand
6. Measure the frictional force of the oil seal
by spring tension gauge
7. Tighten the bearing check/adjusting nut
8. Measure the pre load at the hub bolt by
spring tension gauge/pre load gauge
Note: refer vehicle service manual for
specifications
9. Install the lock washer
10. Tighten the lock nut and bend the lock
washer
11. Clean the work area
12. Store the tools and materials
PRECAUTIONS: Ensuring appropriate use of PPE
Wheel bearing pre load adjusted as per the service manual
ASSESSMENT
CRITERIA:
CHAPTER 2
Analyze kingpin condition
Lesson 2.3: Assemble kingpin assembly
LEARNING GUIDE
Learning Steps
Resources
1. Read the Information Sheet 2.3: on
Information Sheet 2.3
components of kingpin and its functions
2. Read and Perform Operation Sheet 2.3:
on assemble kingpin assembly
Operation Sheet2.3
3. Read and Perform Job Sheet 2.3: On
analyze kingpin condition
Job Sheet 2.3
4. Answer Self Check 2.3 on assemble
kingpin assembly
Sample Self Check 2.3
5. Compare to Model Answer 2.3 on
Model Answer to Self Check 2.3
assemble kingpin assembly
If finished, proceed to lesson 2.4
After completing the activities of this learning unit you should achieve the following:



Identify the components of kingpin
State the function of kingpin components
Assemble kingpin assembly.
INFORMATION SHEET2.3
Components of kingpin
i.
ii.
iii.
iv.
Kingpin bearing
Kingpin bearing cap
Kingpin housing
Kingpin shim
Functions of kingpin components:
1. Kingpin bearing: It allows the wheel to rotate freely as the driver
steer the steering wheel. Most cars have upper and lower bearing on
each wheel.
2. Kingpin bearing cap:
Car have upper and lower kingpin bearing cap on each wheel. It is use to
hold the kingpin bearing while rotating.
3. Kingpin housing: kingpin housing assembly operatively coupling the wheel mounting
assembly, the front axle and the steering assembly with
the help of kingpin. The kingpin housing assembly is
provided with upper and lower arm supports. The
lower arm support provides a new and improved
locking mechanism to keep the kingpin in place.
4. Kingpin shim:
The purpose of the shims is to put a preload on the kingpin
bearings. A spring scale is used to check the preload by
measuring the amount of pull required to turn the knuckle and
also it is use for the camber adjustment of the front wheel.
OPERATION SHEET 2.3
OPERATION TITLE:
Assemble kingpin assembly
PURPOSE:
Steering become hard to steer and gives abnormal noise
during operation which leads to uneven tire wear. so it is
necessary to dismantle kingpin and replace its parts
CONDITIONS OR SITUATIONS
FOR THE OPERATION:
When the following symptoms are observed:
EQUIPMENT, TOOLS AND
MATERIALS:
 Vehicle, set of hand tools, Jack, Safety stand, Kingpin
bearing, Kingpin bearing caps, Grease, Preload gauge
, Kerosene



noisy wheel while in operation
uneven tire wear
hard steering
PROCEDURE:
1. Apply the kingpin bearing with grease
2. Apply the grease in the steering knuckle
3. Install steering knuckle
4. Install the kingpin bearing shims and lower
kingpin bearing cap
5. Adjust kingpin bearing by adding or removing
shims
6. Install the kingpin bearing, shims and steering
knuckle arm
7. Adjust kingpin bearing by adding or removing
shims
8. Connect the steering knuckle arm to drag link
and tie rod end
9. Install axle shaft
10. Install knuckle spindle/stub axle
11. Install backing plate
12. Install wheel hub assembly and disc rotor,
caliper assembly, adjusting nuts and lock nuts
13. Refit the wheel
14. Remove the stand
PRECAUTIONS:
 Ensuring appropriate use of PPE
 Ensuring that the waste grease are disposed safely
ASSESSMENT CRITERIA:
 All steps are followed in correct sequence.
 Components are assembled without damage
 Preload is adjusted as per service manual
JOB SHEET 2.3
JOB TITLE:
Analyze kingpin condition
READING:
Performance guide, service manual, information sheet and operation
sheet.
Analyze kingpin according to standard procedure
OBJECTIVE:
MATERIALS
REQUIRED:
TOOLS &
EQUIPMENT
REQUIRED:
PROCEDURE:
Marking cloth, kingpin, kingpin bearing, and kingpin bearing cap, shims,
grease and kerosene.
 Set of mechanic hand tools
 Floor jack
 Safety stand
 Pre-load gauge
 Special service tools(SST)
Test drive the vehicle
Park the vehicle on the level ground
Remove the kingpin components
Inspect for defective components
Check kingpin condition (bearing, shims and kingpin bearing cap)
for worn out and adjustment, repair and replace if necessary
Replace Faulty kingpin components
Assemble new kingpin components
ASSESSMENT
CRITERIA:
Trainer will use the following criteria during assessment:



All steps are followed in correct sequence.
Components are assembled without damage
Preload is adjusted as per service manual

Self
Check 2.3
SAMPLE OF SELF CHECK 2.3
SECTION A: Short Answer type question
1. List the components of kingpin
2. State the function of kingpin bearing
3. State the function of kingpin bearing cap.
SECTION B: Multiple Choice question/objective type questions
1. The purpose of the shims is to put _______ on the kingpin bearings.
a. Turning force
b. Driving force
c. Preload
d. Thrust load
2. Kingpin shims are used for the adjustment of;
a. Caster angle
b. Camber angle
c. Kingpin axis inclination angle
d. Toe angle

MODEL ANSWER TO A SELF-CHECK 2.3
Model Answer 2.3
SECTION A: Short Answer type question
Ans 1.
i.
Kingpin bearing
ii.
Kingpin bearing cap
iii. Kingpin housing
iv.
Kingpin shim
2. It allows the wheel to rotate freely as the driver steer the steering wheel.
3. It is use to hold the kingpin bearing while rotating.
SECTION B: Multiple Choice question/objective type questions
Ans 1. C
2. b
Bibliography
Anglin, W. H. (2007). Automotive Mechanics. New Delhi: Tata McGraw-Hill.
Anglin, W. H. (2009). Automotive Mechanics. New Delhi: tata Mcgraw Hill Education.
Corporation, M. M. (2002). Automatic Transmission. Mitsubishi Motor Cor[poration.
Fellows, T. A. (1995). Strategies for Effective Teaching a Handbook forTeaching Assistants.
Madison: University of Wisconsin.
Kagan, S. a. (1998). Multiple intelligences: The complete MI book. San Cemente: Kagan
Publishing.
Max Bohner et.al. (1989). Wuppertal: GTZ.
Ontario, Q. P. (2005). Cooperative Learning: Think-Pair-Share Strategy. Online Teaching
Resource , p. 1.
Parrott, P. (2000). Instructional strategies for co teaching and inclusion. Richmond:
University of Richmond.
Singh, D. K. (2009). Automobile Engineering Vol 1. Delhi: Standard Publishers Distributors.
Sweeney, T. (2002). Teaching strategies to improve learning and comprehension. RMC
Research Corporation.
University, Y. (2002). The Teaching Assessment and Evaluation Guide. Senate Committee on
Teaching and Learning.
Whelan, M. (2013, 01 07). electric light. Retrieved from edison tech center:
www.eidsontechcenter.org
www.autocorner.ca. (2013). Retrieved from www.autocorner.ca
CHAPTER 1
Diagnose Suspension System Failures
Lesson 1.1: Suspension Operation Manually
LEARNING GUIDE
Learning Steps
Resources
1. Read the Information Sheet 1.1 Function of
suspension system, types of suspension system,
types of suspension spring, construction and
Information Sheet 1.1
operation of suspension system, sprung weight
and un-sprung weight and suspension
movement
2. Read and Perform Operation Sheet 1.1 on
check suspension operation manually
Operation Sheet 1.1
3. Read and Perform Job Sheet On Diagnose
suspension system failures
Job Sheet
4. Answer Self Check 1.1
Sample Self Check 1.1
5. Compare to Model Answer 1.1
Model Answer to Self Check1.1
If finished, proceed to lesson 1.2
After completing the activities of this learning unit you should achieve the following:
 State the function of suspension system
 State the types of suspension system
 State the types of suspension spring
 Explain the construction and operation of suspension system
 Explain sprung and un-sprung weight
 Explain suspension movement
INFORMATION SHEET 1.1
1.1.1 Function of suspension system
In order to provide comfortable ride to the passengers and avoid additional stresses in the motor car
frame, the car should neither bounce or roll or sway the passengers when cornering nor pitch when
accelerating, braking or sudden lifting or dropping of front wheels in relation to the rear wheels.
Although some of the road irregularities and inequalities are absorbed by modern large tires yet it is
necessary to employ a suspension system for reducing the shocks to passenger and car
A suspension system is located between the vehicle body of the frame and the wheels and designed
to ease the shocks of road surface irregularities and thus improve riding comfort and stability as well
as the tires road holding characteristics.
Therefore the following are the functions of suspension system
a) Support the weight of the vehicle
b) Cushion bumps and irregularities of road
c) Maintain traction between the tires and the road
d) Hold the wheels in alignment
1.1.2 Types of Suspension system
1. Rigid axle suspension
a. Parallel leaf spring type
b. Trailing arm type with twisting beam
c. 4-link type
2. Independent suspension
a. Macpherson strut type
 L-Shaped Lower Arm Macpherson Strut Type
 Dual –link strut type
b. Double wishbone type
 Double wishbone type with coil springs
 Double Wishbone type with torsion bars
c. Semi-trailing arm type
1.1.3 Types of suspension spring
The various suspension springs may be classified as follows
1. Steel spring
a. Leaf spring
b. Tapered leaf spring
c. Coil spring
d. Torsion bar spring
2. Rubber spring
a. Compression spring
b. Compression-shear spring
c. Steel-reinforced spring
d. Progressive spring
e. Face-shear spring
f. Torsional shear spring
3. Plastic spring
4. Air spring
5. Hydraulic spring
1.1.4 Construction and operation of suspension system
a. Rigid axle suspension
In most cars, the rear suspension
must carry most of the extra
weight of the passenger and
luggage. This leads to a difficult
problems: if the suspension
springs are made hard or stiff
enough to handle this extra load,
they will be too hard for when
there is only the driver; on the
other hand, if they are made soft
enough for when there is only the
driver, they will be too soft for when the car is fully loaded. The same also applies to the shock
absorbers. This problem can be solved by using leaf spring or other types of springs having a
variable spring rate, gas-filled shock absorbers, different types of independent suspension, etc.
In vehicles having a rigid axle suspension system, the right and left wheels are connected by a single
axle which itself is fitted to the body and the frame via springs (leaf springs or coil springs) due to its
great strength and simple construction, the rigid axle suspension system is widely used with the front
and rear wheels of buses and trucks and with the rear wheels of passenger cars.
Types of rigid suspension are:
 Parallel leaf spring type
 Trailing arm type with twisting beam
 4-link type
Parallel leaf spring type
This is the rigid axle
suspension which is most
generally used for the rear
suspension of commercial
vehicles.
Construction
The type of axle generally
used with a parallel leaf
spring type suspension is also
called live axle, in which the
differential, axle shafts, and
wheel hub mounting are
combined into one rigid unit. The live axle is connected to the propeller shaft and is attached to the
frame in such way as to allow it (the axle) to move up and down its springs, and to cope with the
loads and the braking and driving forces imposed upon it.
Trailing arm type with twisting beam
This is a rigid axle suspension which is used for the rear suspension of small front-wheel drive cars.
Construction
The rear ends of
suspension arms are
welded to the axle
beam, which houses the
stabilizer. Both ends of
the stabilizer are also
welded to the same axle
beam. Loads applied
from tires are therefore
broken down into their
directional components
for distribution as show
in the chart below.
Coil springs
Vertical
Shock absorber and lower bushings
Longitudinal
Lateral
Upper support rubber cushions
Suspension arms and front bushings
Lateral rod and bushing
When the wheels bound and rebound in the opposite directions, the twisting movement of the ends of
the suspension arms is translated into a twisting of the rear axle beam, built-in stabilizer and rear
suspension arms. The twisting of the rear axle beam and stabilizer generates a reactive force which
opposes the twisting of the suspension arms, aiding the coil springs in providing roll rigidity to
minimize body rolling, thus yielding greater steering stability.
Roll rigidity is the sum of the increases in front and rear suspension recovery moments that are
produced when the vehicle rolls from side to side, and which are transmitted from the front and rear
suspension to the body.
4-LINK TYPE
Of the various types of rigid axle suspensions, this suspension provides superior riding comforts,
since it handles axle positioning and load suspension separately. Ordinarily, coil springs are used as
suspension springs.
CONSTRUCTION
Axle positioning is carried out by
two lower control arms, two upper
control arms and one lateral
control rod. For load suspension
and absorption of road shock, only
the springs are used.
Reactive force to wheels driving
and braking torques (which act in
the
vehicle’s
longitudinal
direction) are handle by the lower
and upper control arms, and lateral
forces by the lateral control rod.
One end of each control arm, or
one end of the lateral rod, is
fastened to the body or the frame and the other ends are attached to the rear axle housing via rubber
bushings.
Coil springs are mounted between the lower control arms or rear axle housing and the body.
b. Independent Suspension
In vehicles having an independent
suspension system, the right and left
wheels are not connected directly by an
axle. The suspension is fitted to the body
and the frame in such a way that wheels
can move
independently without
affecting each other. The independent
suspension is commonly used with front
wheels of the passenger cars and small
trucks and more recently with the real
wheels of passenger cars as well.
Types of independent suspension are:



Macpherson strut type
Double wishbone type
Semi-trailing arm type
Macpherson strut type
This is the most widely used independent suspension systems for the front suspension of small and
medium sized cars.
The strut type suspension is composed of the lower arms, strut
bars, stabilizer bar and strut assemblies
 One end of the lower arm is attached to the suspension
member via rubber bushing, and can move freely up and
down. The other end is mounted on the steering knuckle
arm by means of ball joint.
 The strut bars withstand the force being exerted from the
wheels in the longitudinal direction. One end is fastened
to the lower arm and the other end is mounted via a
rubber cushion to a strut bar bracket welded to the front
cross member.
 The stabilizer bar helps to maintain the vehicle level on
corners and gives the tire better road holding
characteristics. It is fitted at both end to the lower
suspension arm via rubber bushings and links, and at two
centre points to the body via rubber bushings.
 The coil springs are mounted on the strut assembly, and
the shock absorber is build into the strut assembly.
L-SHAPED LOWER ARM MACPHERSON STRUT TYPE
Construction
There are several lower-arm
configurations being used to
support the wheels and car body.
Some front- engine, front- wheeldrive vehicles employ L-shaped
lower arms are mounted to the
body at two points, via bushings,
and at one more point to the
steering knuckle via the ball joint.
This type of arm can withstand
both lateral and longitudinal
forces, thus making it possible to
eliminate the strut bar.
Dual –link strut type
This type of suspension is used in the rear of the front –engine front -wheel- drive cars and is one
type of strut suspension
Construction
The wheel are supported by two suspension arms which are nearly perpendicular to the vehicles
longitudinal centre line, and by strut rods running parallel to this centre line. The longitudinal, lateral
and vertical loads from the wheels up-down motions and each borne by different components.
Therefore, it is possible for each of the components to have the most appropriate design for the
vehicle, superior handling stability and riding comfort can be realized with this suspension.
Force and loads from various directions are applied to the following components:
Vertical
Coil springs
Shock absorber
Longitudinal
Lateral
Double wishbone type
a. Double wishbone type with coil springs
b. Double Wishbone type with torsion bars
Double wishbone type with coil springs
This type of independent suspension
system is used widely as the front
suspension of passenger car and
small trucks.
The wheel is fitted to the body via a
pair of suspension arm (upper and
lower arm)
The shock absorber and coil springs
are mounted inside the quadrilateral
formed by these two arms, the
steering knuckle and the frame.
One of each suspension arm is fitted
to the body or frame via bushings,
and the other end to the steering
Strut rod and bushings
Upper support rubber cushions
Suspension arms and bushings
knuckle via a ball joint. The top of the shock absorber is fitted to the body or frame, and the bottom
to the lower arm. The coil spring is fastened between the lower arm and the body or frame.
Double Wishbone type with torsion bars
This type of suspension is used on
many small trucks in place of a
suspension system with coil
springs.
Shown below is the torsion bar
fitted to the upper arm. The lower
arm is connected to the
suspension member by a rubber
bushing.
The upper arm is joined to the
upper arm shaft by rubber
bushings. The torque arm is
attached to the rear of the upper
arm by two bolts and the torsion
bar is splined to it.
The front of each torsion bar is splined to the torque arm of the upper arm, and the rear of the bar fits
into anchor arms, which is attached to the cross member by the anchor arm adjusting bolts. It is
therefore easy to adjust the height of the vehicle using this bolt. The front and rear splined are each
provided a dust cover to keep out muddy water
Semi-trailing arm type
This is an independent suspension system design with the
objectives of increasing rigidity with respect to lateral loads
and minimizing changes in alignment (toe-in, tread and
camber) that occur due to the up and down motion of the
wheels.
Generally, the construction is simple and the components
take up little space, so it often used as the rear suspension
on passenger cars.
The swing axis of the suspension arms are located forward
of the wheels, and the arms are installed via bushing to the
suspension members so that there axis are at an angle with
respect to the vehicles longitudinal centreline.
The differential is carried by a differential support member
mounted on the body via bushings. Also, CV (constant
velocity) joints are normally used as joint in the drive shaft.
1.1.4 Sprung and Unsprung weight
The body is supported by springs. The weight of the body, etc, which is supported by spring is called
the sprung weight. On the other hand, the wheel and axles, and other parts of the automobile which
are not supported by springs, make up the un-sprung weight
UNSPRUNG WEIGHT.
It is generally said that the greater the sprung weight of an automobile, the better the riding comfort
becomes, because, as the sprung weight made larger, the tendency of the body to be jerk decreases.
Conversely, if the un-sprung weight is large, it is easy for the body to be jolted.
Oscillation and jolting of the sprung parts of the vehicle-specially the body – have a particularly
great effect on riding comfort.
1.1.6 Suspension movement
Suspension movement can be also called as oscillation and jolting. This oscillation and jolting can be
classified as follows:
1. Oscillation of sprung weight
2. Oscillation of un-sprung weight
Oscillation of sprung weight
Pitching
Pitching is the up-and-down oscillation, in relation to the car’s center of gravity, of the front and
back of the car. This happens especially when the car goes over larger ruts or bumps in the road or
when driving over an unpaved road which is rough and full of potholes. Also, pitching occurs more
easily in vehicles with softer spring than in those with harder springs.
Rolling
When turning or when driving on a bumpy road, the springs on one side of the vehicle expand,
while those on the other side contract. This results in body rolling in the lateral (side-to-side)
direction.
Bouncing
Bouncing is the up-and-down movement of the auto body as a hole. When car is running at high
speeds on an undulating surface, bouncing is likely to occur. Also, it occurs easily when the springs
are soft.
Yawing
Yawing is the movement of the car’s longitudinal centerline to the right and left, in relation to the
car’s center of gravity. On roads where pitching occurs, yawing is also likely to occur.
Oscillation of un-sprung weight
Hopping
Hopping is the up-and-down bouncing of the wheels which usually occurs on corrugated roads
while driving at medium and high speeds.
Tramping
Tramping is the up-and-down oscillation in opposite directions of the left and right wheels, causing
the wheels to skip over the road surface. This occurs most easily in vehicles with rigid axle
suspension.
Wind-up
Wind-up is the phenomenon in which the leaf springs attempt to wind themselves around the axle
due to the driving torque
OPERATION SHEET 1.1
OPERATION TITTLE:
Check suspension operation manually
PURPOSE:
To determine the faults in suspension system
CONDITIONS OR SITUATIONS FOR Upon hearing abnormal sound or rough ride while driving
THE OPERATION:
EQUIPMENT, TOOLS AND
MATERIALS:


Vehicle
Wheel wedge
PROCEDURES:
1.
2.
3.
4.
5.
Park the vehicle on the level ground
Recommend for replacement
Rock the vehicle
Determine the faulty components
Wedge the wheels
PRECAUTIONS:

Ensuring vehicle is parked safely
ASSESMENT CRITERIA:


Vehicle is parked safely
Faulty components are determined and recommended
for replacement

SAMPLE OF SELF CHECK 1.1
Self Check 1.1
SECTION A: Short Answer type question
1. State the function of suspension system
2. List down the main type of suspension system
3. List down the suspension movement of sprung weight
SECTION B: Multiple Choice question/objective type questions
1. Following are the types of rigid suspension except
a. Parallel leaf spring type
b. Trailing arm type with twisting beam
c. 4-link type
d. Dual –link strut type
2. The up-and-down oscillation, in relation to the car’s center of gravity, of the front and back
of the car is called
a.
b.
c.
d.
Pitching
Rolling
Bouncing
Yawing
3. Torsional shear spring is one of the type of suspension
a. Steel spring
b. Rubber spring
c. Air spring
d. Plastic spring
SECTION C: True/false or matching type question
State true or false for the following statement
1. Hopping ,Tramping and Wind-up are the oscillation of sprung weight
2. The other parts of the automobile which are not supported by springs is called un-sprung
weight
3. Macpherson strut type, Double wishbone type and Semi-trailing arm type are the types of
independent suspension
SECTION D: Explanation type/open ended type question
1. Explain the construction of double wishbone type with coil springs independent suspension
2. Differentiate between sprung and un-sprung weight with the help of diagram

MODEL ANSWER TO A SELF-CHECK 1.1
Model Answer 1.1
SECTION A: Short Answer type question
1. State the function of suspension system
Answer. The following are the function of suspension system
a) Support the weight of the vehicle
b) Cushion bumps and irregularities of road
c) Maintain traction between the tires and the road
d) Hold the wheels in alignment
2. List down the main type of suspension system
Answer. Main types of suspension system are
a. Rigid suspension
b. Independent suspension
3. List down the suspension movement of sprung weight
Answer. Suspension movements of sprung weight are
a.
b.
c.
d.
Pitching
Rolling
Yawing
Bouncing
SECTION B: Multiple Choice question/objective type questions
1. Following are the types of rigid suspension except
e. Parallel leaf spring type
f. Trailing arm type with twisting beam
g. 4-link type
h. Dual –link strut type
2. The up-and-down oscillation, in relation to the car’s center of gravity, of the front and back
of the car is called
e.
f.
g.
h.
Pitching
Rolling
Bouncing
Yawing
3. Torsional shear spring is one of the type of suspension
e. Steel spring
f. Rubber spring
g. Air spring
h. Plastic spring
SECTION C: True/false or matching type question
State true or false for the following statement
1. Hopping ,Tramping and Wind-up are the oscillation of sprung weight False
2. The other parts of the automobile which are not supported by springs is called un-sprung
weight True
3. Macpherson strut type, Double wishbone type and Semi-trailing arm type are the types of
independent suspension True
SECTION D: Explanation type/open ended type question
1. Explain the construction of double wishbone type with coil springs independent
suspension
Answer. This type of independent suspension system is used widely as the front suspension of passenger
car and small trucks.
The wheel is fitted to the body via a pair of suspension arm (upper and lower arm)
The shock absorber and coil springs are mounted inside the quadrilateral formed by these two arms, the
steering knuckle and the frame.
One of each suspension arm is fitted to the body or frame via bushings, and the other end to the steering
knuckle via a ball joint. The top of the shock absorber is fitted to the body or frame, and the bottom to the
lower arm. The coil spring is fastened between the lower arm and the body or frame.
2. Differentiate between sprung and un-sprung weight with the help of diagram
Answer.
Sprung weight- The weight of the body, etc, which is supported by spring is called the sprung
weight.
Un-sprung weight- other parts of the automobile which are not supported by springs, make up the
un-sprung weight
JOB SHEET 1.1
JOB TITLE:
Diagnose Suspension System Failure
READING:
Refer manuals, information sheet and operation sheets.
OBJECTIVE:
To troubleshoot suspension system failure
MATERIALS
REQUIRED:
Vehicle and Wheel wedge
TOOLS &
EQUIPMENT
REQUIRED:
Car lift, Hydraulic floor jack
PROCEDURE:
Collect required tools, materials and equipment
Park the vehicle on ramp or lift the car
Check the suspension components manually
Perform visual inspection
Perform test drive to troubleshoot suspension system failure
Trainer will use the following criteria during assessment:
ASSESSMENT
CRITERIA:
 All operation steps were completed in the correct sequence.
 All safety precautions were followed while using the tools and
equipment.
 Defective suspension components are identified
Lesson 1.2 Visual inspection of suspension system
LEARNING GUIDE
Learning Steps
1. Read
the
Information
Resources
Sheet
1.2
on
Components of suspension system and Information Sheet 1.2
types of suspension defects
2. Read and perform skill sheet 1.2 on use of
Skill sheet 1.2
car lift
3. Read and Perform Operation Sheet 1.2 on
perform visual inspection
Operation Sheet 1.2
4. Answer Self Check 1.2
Sample Self Check 1.2
5. Compare to Model Answer 1.2
Model Answer to Self Check1.2
If finished, proceed to lesson 1.3
After completing the activities of this learning unit you should achieve the following:
 State the components of suspension system
 State the types of suspension defect
INFORMATION SHEET 1.2
1.2.1 Components of suspension system
Component of suspension system are;
a. Shock absorber
A shock absorber is a suspension component
that controls the up-and-down motion of the
vehicle’s wheels. OR
A device used to absorb mechanical shocks, as
a hydraulic or pneumatic piston used to
dampen the jarring sustained in a moving
motor vehicle. OR
A shock absorber is a tubular hydraulic device
placed near each wheel to control or dampen
spring oscillations.
b. Stabilizer bar
Stabilizer bar is a hollow or solid bar
connecting the right and left suspension
c. Lateral control rod
The lateral rod is mounted transversely
between the axle and a structural member
d. Springs
Springs are designed to prevent shocks from
the road surface and vibration of the wheels
from reaching the vehicle body directly
e. Suspension arm
f. Strut rod (bar)
g. Ball joints
A joint that allows the control arm and
steering knuckle to move up and down and
sideways as well
h. Rubber bushing: separates the faces of
two metal objects while allowing a
certain amount of movement. This
movement allows the suspension parts
to move freely, for example, when
travelling over a large bump, while
minimizing transmission of noise and
small vibrations through to the chassis
of the vehicle.
i. Torsion bar spring
1.2.2 Types of defect
The suspension system holds up the vehicle and its load. It keeps the axles in place. Therefore, broken
suspension parts can be extremely dangerous. Always check the suspension system during your pre-trip
and report any defects to breakdown.
a. Leaking shock absorbers.
b. Torque rod or arm, u-bolts, spring hangers, or other axle positioning parts that are cracked,
damaged, or missing.
c. Any loose, cracked, broken, or missing frame members.
SKILL SHEET 1.2.3
SKILL TITLE:
Use car lift
EQUIPMENT, TOOLS AND
MATERIALS:
vehicle and car lift
PROCEDURE:
1. Check hoist instructions
2. Close all vehicle doors and drive the vehicle into lift area
3. Check Safe Working Load (SWL) of lift against Gross Vehicle Mass (GVM)
4. GVM can usually be found in the vehicle manual
5. Swing arms of car lift under vehicle and position pads in correct place
6. Lift pads must be positioned under a strong point on the vehicle body. Eg. Where metal is
thickest or where elements join
7. Operation requires use of two hands. This is a safety feature, to keep the operator away from
the hoist area while lifting is occurring
8. Operate lift to raise pads to within a few mm of vehicle lift point. Check and readjust lift pad
position if necessary
9. A locking mechanism is provided to minimizes the distance the load will fall if something is
gone wrong while lifting
10. After final checking is done raise the vehicle
OPERATION SHEET 1.2
OPERATION TITLE:
Perform visual inspection
PURPOSE:
To determine the defects or faulty components of
suspension system
CONDITIONS OR SITUATIONS
FOR THE OPERATION:
When following symptom are observed
EQUIPMENT, TOOLS AND
MATERIALS:
Vehicle, Ramp, Car Lift, Wheel wedge and PPE


Rough ride
Noises in the suspension system
PROCEDURE:
1. Park the vehicle on the ramp/lift
2. Inspect the faulty components
3. Determine the faulty components
4. Recommend for replacement
5. Wedge the wheels
PRECAUTIONS:
 Ensure vehicle is parked/lifted safely
 Ensure lift is operated as per standard procedures and locked
 Ensure PPE is used during visual inspection
ASSESSMENT CRITERIA:
 Vehicle is parked/lifted safely
 Faulty components are determined and recommended for replacement

Self Check 1.2
SAMPLE OF SELF CHECK 1.2
SECTION A: Short Answer type question
1. List down the components of suspension system

Model Answer 1.2
:
MODEL ANSWER TO A SELF-CHECK 1.2
1. List down the components of suspension system
Answer: Components of suspension system are
a)
b)
c)
d)
e)
f)
g)
h)
i)
Shock absorber
Stabilizer bar
Lateral control rod
Springs
Suspension arm
Strut rod (bar)
Ball joints
Rubber bushing
Torsion bar spring
Lesson 1.3: Test drive
LEARNING GUIDE
Learning Steps
Resources
1. Read the Information Sheet 1.3 on
symptoms, causes and remedial measures Information Sheet 1.3
of suspension failures
2. Read and Perform Operation Sheet 1.3 on Operation Sheet 1.3
perform test drive
3. Answer Self Check 1.3
Sample Self Check 1.3
4. Compare to Model Answer 1.3
Model Answer to Self Check1.3
If finished, proceed to chapter
After completing the activities of this learning unit you should achieve the following:



State the symptoms of suspension system failure
State the causes of each symptom of suspension system failure
State the remedial measure for each causes of suspension system failure
INFORMATION SHEET 1.3
1.3.1 Symptoms, causes and remedial measure of suspension failures
Sl.no
Fault
1.
Front wheel low i.
ii.
speed shimmy
iii.
iv.
v.
vi.
2.
Front
tramp
3.
Rough ride
4.
5.
6.
7.
Cause
wheel i.
ii.
iii.
Uneven tyre pressure
Loose ball joints or king-pin
Front springs soft
Irregular tire tread
Loose linkage
Looseness in steering gear.
Wheels unbalanced
Excessive wheel run out
Shock absorber defective
i. Excessive tire pressure
ii. Shock absorber defective
iii. Excessive friction in suspension
Remedy
i.
ii.
iii.
iv.
v.
vi.
i.
ii.
iii.
Inflate to correct pressure
Replace
Replace
Match treads
Readjust. Replace worm
parts
Replace worn parts
Rebalance
Replace
Replace
i. Reduce
to
correct
pressure
ii. Replace
iii. Lubricate parts
i. Stabilizer bar loose
i. Tightened as required
Sway on turn
ii. Sagging or weak spring
ii. Replace
iii. Incorrect caster
iii. Re-adjust
i. Avoid
Breakage
of i. Overloading
ii.
Loose
centre
bolt
ii. Tightened centre bolt
spring
iii. Loose U-bolt
iii. Tightened U-bolt
iv. Defective shock absorber
iv. Replace
v. Tight spring shackle
v. Loosen as necessary
i.
Leaf
broken
i. Replace
Sagging spring
ii. Weak spring
ii. Replace
iii. Short coil spring
iii. Install shim or replace
iv. Defective shock absorber
iv. replace
Noises in the Commonly attributed to any loose, Examine the parts carefully.
suspension
worn or un-lubricated part such as Locate the cause and correct
system
U-bolts, rebound clips, shackles, as required.
shock absorbers linkage and etc.
OPERATION SHEET 1.3
OPERATION TITLE:
Perform test drive
PURPOSE:
To diagnose suspension system failure
CONDITIONS OR SITUATIONS
FOR THE OPERATION:
when there is problem with suspension system
EQUIPMENT, TOOLS AND
MATERIALS:
Vehicle and On test plate
PROCEDURE:
1. Note the customer complaint
2. Display the ON TEST plate
3. Start the engine
4. Move/drive the vehicle on different
road conditions
5. Trace the symptoms (Sound, jerk,
vibration)
6. Recommend for repair/replace
7. Determine the defective parts
PRECAUTIONS:
 Ensure that safety belt is fasted
 Ensure that speed limit is maintained
ASSESSMENT CRITERIA:
 Test drive is performed as required
 Suspension failure symptoms are identified
 Faulty parts are identified

Self Check 1.3
SAMPLE OF SELF CHECK 1.3
SECTION A: Short Answer type question
1. List down the symptoms of suspension system failure
2. What would be the causes and remedies when there is rough ride?
SECTION B: Multiple Choice question/objective type questions
1. Following are the causes of Sagging spring except
a. Weak spring
b. Short coil spring
c. Overloading
d. Defective shock absorber
2. Noises in the suspension system is mainly caused by
a. Un-lubricated part
b. Overloading
c. Defective shock absorber
d. Tight spring shackle

MODEL ANSWER TO A SELF-CHECK 1.3
Model Answer 1.3
SECTION A: Short Answer type question
1. List down the symptoms of suspension system failure
Answer. Symptoms of suspension system failure are
a. Front wheel low speed shimmy
b. Front wheel tramp
c. Rough ride
d. Sway on turn
e. Breakage of spring
f. Sagging spring
g. Noises in the suspension system
2. What would be the causes and remedies when there is rough ride?
Answer.
Trouble
Rough ride
Causes
1. Excessive tire pressure
2. Shock absorber defective
3. Excessive friction in suspension
Remedies
1. Reduce to correct pressure
2. Replace
3. Lubricate parts
SECTION B: Multiple Choice question/objective type questions
1. Following are the causes of Sagging spring except
a. Weak spring
b. Short coil spring
c. Overloading
d. Defective shock absorber
2. Noises in the suspension system is mainly caused by
a. Un-lubricated part
b. Overloading
c. Defective shock absorber
d. Tight spring shackle
Reference

Anglin, D. L. (n.d.). Automotive Mechanics. In D. L. Anglin, Automotive Mechanics.

H.Gerschler. (n.d.). Technology for the automotive trade Volume 1. In H.Gerschler, Technology
for the automotive trade Volume 1.

Singh, D. K. (2008). In D. K. Singh, Automobile Engineering Vol.1. Delhi.
CHAPTER 2
Replace Faulty Rigid Suspension Components
Lesson 2.1: Shock Absorber
LEARNING GUIDE
Learning Steps
Resources
1. Read the Information Sheet 2.1 on types of
shock absorber, function of shock absorber and Information Sheet 2.1
operation of shock absorber
2. Read and Perform Operation Sheet 2.1 on
replace shock absorber
Operation Sheet 2.1
3. Read and Perform Job Sheet On Replace
faulty rigid suspension system
Job Sheet
4. Answer Self Check 2.1
Sample Self Check 2.1
5. Compare to Model Answer 2.1
Model Answer to Self Check 2.1
If finished, proceed to lesson 2.2
After completing the activities of this learning unit you should achieve the following:
 State the types of shock absorber
 State the function of shock absorber
 Explain the operation of shock absorber
INFORMATION SHEET 2.1
2.1.1 Types of shock absorber
Shock absorbers are classified according to their operation, construction, and by their working
medium.
1. Classification by operation
a. Single-action shock absorber
b. Multiple-action shock absorber
2. Classification by construction
a. Twin-tube shock absorber
 Gas charged twin tube shock absorber
 Position sensitive damping (PSD) twin tube shock absorber
 Acceleration sensitive damping (ASD) twin tube shock absorber
b. Mono tube shock absorber
3. Classification by working medium
a. Hydraulic shock absorber
 Direct acting shock absorber
b. Cam actuated piston type hydraulic shock absorber
 Double acting shock absorber
 Single acting shock absorber
c. Rotary vane type hydraulic shock absorber
 Gas filled shock absorber
2.1.2 Function of shock absorber
The shock absorbers control the spring action, slowing it down on both compression and rebound
and thus prevent bouncing.
The following are the function of shock absorber:
1. Limit Vehicle Body Movement
The main purpose of shock absorbers is to limit overall vehicle body movement, or sway. As a
vehicle is driven, the body will move up and down or side to side to various degrees in response to
driving and road conditions. These types of vehicle movements are held in check by shock absorbers.
2. Stabilize Vehicle Ride
Depending on road conditions or driving style, a vehicle can go from smooth and controlled to
bumpy and erratic in a short time period. Shock absorbers stabilize the overall vehicle ride,
preventing an excess of vehicle body lean or roll in any one direction, especially when cornering or
navigating sharp turns. This stabilization allows for greater vehicle control and stability.
3. Stabilize Vehicle Tires
Most vehicles have one shock absorber per vehicle tire. Each individual shock absorber, in addition
to controlling vehicle body movement and ride, exerts a tremendous stabilizing force on each vehicle
tire. A shock absorber prevents a vehicle's tire from hopping or bouncing in uneven or choppy terrain
and helps to a vehicle tire planted firmly on the ground or road surface.
4. Minimize Tire Wear
By helping to stabilize and control the movements of a vehicle tire, a shock absorber helps to
minimize tire tread wear. Tires that are held firmly against the ground and held in position by a firm
shock absorber last longer and experience much less treads wear.
5. Reduce Overall Suspension Wear
Shock absorbers are only part of a vehicle's overall suspension system. Most vehicles utilize a
combination of various leaf springs, coil springs and struts to stabilize and control a vehicle's
movement. Shock absorbers basically absorb and deflect a great deal of initial road impacts and/or
body movements. What shock absorbers can't contain gets passed on to other parts of a vehicle's
suspension system.
2.1.3 Operation of shock absorber
1. Classification by operation
c. Single-action shock absorber
d. Multiple-action shock absorber
 Single-action shock Absorber
Damping occurs only when the shock
absorber is extended. No damping force is
generated when it is compressed.
Multiple-action Shock Absorber
Damping occurs both when the shock
absorber is extended and when it is
compressed. Currently, most shock
absorbers are used on cars is of this type.
2. Classification by construction
a. Twin-tube shock absorber
 Gas charged twin tube shock absorber
 Position sensitive damping (PSD) twin tube shock absorber
 Acceleration sensitive damping (ASD) twin tube shock absorber
b. Mono tube shock absorber
Twin-tube shock absorber
A twin tube shock or the Twin tube shock
absorber is a low pressure shock having tube
inside the outer shock body which contains
the piston assembly. In order to create
damping force, different coil springs inside
the shock body are used. The inner tube is
known as pressure tube whereas the outer tube
is known as the reserve tube. The reserve tube
is used for storing different types of hydraulic
fluid. The mounts used for the shock absorber
are many but the most popularly used rubber
mount is rubber bushings between the shock
absorber and the suspension for minimizing
suspension
vibration.
The piston rod passes to the upper end of the
pressure tube through rod guide and the seal.
The rod guide assists the piston to move
freely inside whereas the oil is kept inside by
the seal. The movement of the fluid is
controlled by the base valve which is located
at the bottom of the pressure tube.
Working of a Twin Tube Shock Absorber
The pushing of the piston results in the flow of the oil without resistance from below the piston
through different outlets to the area above the piston. The oil displaced the rod flows into the
reservoir tube filled with air. The oil encounters the resistance while passing through the foot valve
thereby generating the bump damping.
The oil above the piston is pressurized and when the piston rod is pulled out which the flows through
the piston. The oil when encounters an resistance while passing through the piston, generates the
rebound damping.
Types of Twin Tube Shock Absorber
Twin tube shock absorber can be of different types depending on the mechanism used.
Some of the popular types are as follows:
a. Gas Charged Twin Tube Shock Absorber
Gas charged shock absorber solved many problems associated with driving. The design
uses low pressure charge of nitrogen gas in the reserve tube. The pressure of the gas may
vary and depends upon the amount of fluid in the reserve tube.
The gas helps in minimizing the aeration of the hydraulic fluid. The creation of foam is prevented
because the gas compresses air bubbles in the hydraulic fluid. Reduction of aeration enhances the
working capacity of the shocks. This shock absorber gives more flexibility to the engineers to design
valve. The additional advantage of the shock absorber is that it creates a mild boost in spring rate to
the vehicle.
Benefits of Gas Charged Twin Shock Absorber

The handling is improved through roll reduction and the reduction of sway and dive.

It reduces aeration and gives smooth control in different types of road conditions.

The heat may lead to the reduction of damping capability in the shock absorber however in
gas charged shocks this is reduced to a considerable extent.
Position Sensitive Damping (PSD) Twin Tube Shock Absorber
Twin tube shock PSD design is a new technology in the field of shock absorber. In this twin shock
absorber, the position of the valve within the pressure tube is taken into account. The pressure tube
contains the tapered grooves which enables optimal ride comfort and added control. The grooves in
effect create two zones within the pressure tube.
In the first zone, the tapered grooves allow hydraulic fluid to pass freely around and through the
piston thereby reducing the resistance on the piston and ensuring a smooth, comfortable ride. The
first zone is utilized in case of normal ride. In case of demanding situations, second zone called as
control zone is utilized. The fluid flow towards the piston valving for more control of the vehicle's
suspension which gives better control.
Advantages



Give fine and smooth ride.
It can adapt itself quickly to different road and weight conditions.
It has two shocks in itself that is-comfort and control
Acceleration Sensitive Damping (ASD) Twin Tube Shocker
Twin tube ASD shocker brings the benefits of both the comfort and the control. Twin tube
ASD design shocker uses the compression valve which provides a bypass to fluid flow
around the compression valve. The compression valve is designed in such a way that it
senses a bump in the road and adjusts the shock automatically to absorb the impact thereby giving
greater control to the shock
Mono tube Shock absorber
Mono tube shock absorber or mono tube shock regulates the flow of the oil between the
compression and compensation chambers by using mechanically fixed base valve. The
shock also utilizes compressible bladder in the compensation chamber for allowing volume
compensation. The use of base valve and the compressible bladder together eliminate the
need for pressurized gas and a floating piston which were the important features of the traditional
mono tube dampers.
How it works?
In mono tube design, the damping force is
created by deflective discs which are heat
treated stainless spring steel. The discs are
generally stacked in a pyramid pattern. The
shim with the largest diameter faces the
piston. The disc which is in close proximity
to piston open first and allows the flow of
the oil. The rate of the shock both on
compression and rebound can be changed
by increasing thickness and sometimes
diameters.
Mono tube shock absorber consists of two
chambers which are stacked on each other
and are separated by a "floating piston".
Both the piston is filled with oil and gas respectively. In the oil filled chamber damping forces are
created. The gas chamber is separated by a floating piston. The compression of shock results in the
compression of the air chamber by the floating piston which displaces the volume of the shaft. This
type of pressure creates the rod-pressure.
The pushing of piston rod also forces the floating piston towards downwards thereby increasing
pressure in both gas and oil section. This also results in the flow of the oil through the piston. This
type of resistance generates the bump damping.
Rebound damping is produced when the oil between piston and guide is forced to flow through the
piston. This happens when the piston is pulled out.
Benefits
1.
2.
3.
4.
5.
6.
Gives good control and smooth ride.
Mono tube Shocks Can is mounted at any angle.
It is lighter as compared to equivalent twin tube designs.
Has high severity life.
Adjusts to road conditions automatically.
Features
The features of the mono tube shock absorber include:
7. It has distinctive mono disc design.
8. The vehicle can be assembled easily.
9. Weight is light.
10. Element of lag and fade is absent.
11. Reliable and durable.
12. It also comes in controlled ride application.
Features
The features of the mono tube shock absorber include:
 It has distinctive mono disc design.





The vehicle can be assembled easily.
Weight is light.
Element of lag and fade is absent.
Reliable and durable.
It also comes in controlled ride application.
3. Classification by working medium
a. Hydraulic shock absorber
 Direct acting shock absorber
b. Cam actuated piston type hydraulic shock absorber
 Double acting shock absorber
 Single acting shock absorber
c. Rotary vane type hydraulic shock absorber
 Gas filled shock absorber
Hydraulic shock absorber
This is an ordinary shock absorber which uses only a fluid (shock absorber fluid) as a working
medium.
In hydraulic shock absorber, fluid is tended to pass through a tiny hole which resists the movement
of fluid. This resistance create friction in the fluid which gives rise to heat. Fluid in the shock
absorber swallows this heat generates due to spring action and thus energy of motion is absorbed.
Thus, the road shock is absorbed by converting energy of motion into heat which is absorbed in the
fluid of shock absorber.
Hydraulic shock absorbers can be classified as under:
1. Direct acting
2. Cam actuated piston type
3. Rotary vane type
Direct acting hydraulic shock absorber
One end of this type of shock absorber is connected to axle whereas other to the chassis frame. It
checks both compression and rebounce of the road spring.
Construction
There are two chambers in this type of shock absorber. The outer chamber serves as a reservoir in
which the inner chamber is housed which act as cylinder. The cylinder contains a combine piston and
valve which is connected to a rod. The combined piston and valve divides the cylinder into two
chambers-upper and lower. The upper chamber of cylinder is called rebound chamber whereas lower
one is called compression chamber.
Operation
When the road spring is compressed, combined piston and valve moves into the lower chamber of
the cylinder, compressing fluid in this chamber. Since the fluid is incompressible, so it opens the
valve connected with piston and enters into upper chamber of the cylinder. Some of the fluid runs
into the outer chamber by opening the inlet and compression valve located at the bottom of the
cylinder.
When road spring comes at rebound, the fluid resistance in the shock absorber puts its effect on it.
As soon as the combined piston and valve is pulled up, valve with piston is closed but due to
increased in pressure, it opens out to other direction as this is double type of check valve. Opening of
the valve in the other direction tends the fluid to flow from upper to lower chamber of the cylinder.
This type of shock absorber is also known as telescopic shock absorber as it moves up and down in
one line during its working just like the telescope barrel.
Cam actuated piston type hydraulic shock absorber.
This type of shock absorber is both of single acting and double acting type.
a. Double acting shock absorber
This type of shock absorber contains two pistons, one of which is rebound whereas other is
compression piston. These pistons are actuated by a cam fitted on a shaft. There is a lever attached to
camshaft, which actuates the cam thereby resulting in the movement of piston.
Every piston contains one intake and one relief valve each. Fluid is transferred from one chamber to
other through these valves.
During compression of road spring, the fluid goes out from compression chamber through relief
valve and enters into the reservoir. During this process, compression of the road spring is checked
up. During the same process, fluid enters into rebound chamber through the rebound valve.
During rebound of road spring, the fluid goes out of rebound chamber through relief valve and enters
into the reservoir and rebound of the spring is checked up. In the mean time, fluid enters into
compression chamber through the intake valve.
b. Single Acting shock absorber
This type of shock absorber, there is only one piston and one intake and on relief valve. When the
wheel strikes a bump, the road springs are compressed and car frame moves downward, carrying the
shock absorber with it. This causes the shock absorber arm to move upward, relieving the cam
pressure on the piston. Release in pressure by the cam allows the piston spring to force the piston
outward, creating vacuum behind the piston. The vacuum causes the intake valve under the head of
piston to open, permitting the fluid to flow under piston head and fill the piston chamber.
As the wheels passes over the bump, the car spring rebound, and the car frame moves forward,
carrying shock absorber with it. This causes the shock absorber arm to move downwards, applying
cam pressure on the piston. Cam forces the piston into the cylinder, closing the intake valve. The oil
trapped in the cylinder, forces the relief valve off its seats and goes out slowly into the reservoir.
Rebounding of road spring is thus damped out by this action.
Rotary vane type hydraulic shock absorber
This type of shock absorber contains a round chamber in which are two-lobe rotor moves in the
viscous fluid. The main chamber contains two-fixed vanes, spring, oil seal, cover and link. When in
assembled state, the main chamber is divided into four part. When the rotor is moved, fluid is under
pressure in two chambers because of the construction of valves which allows very little fluid to flow
toward chamber having less pressure. When the rotor moves in the reverse direction, high pressure
chambers are converted into low pressure ones.
The chambers of the shock absorber are kept filled with fluid automatically so that the effect of it
action may not decrease.
The rotor shaft is operated by an actuating arm which is connected with axle by means of a link.
This type of shock absorber is very popular with ford vehicles.
Gas filled shock absorber
This is a hydraulic absorber which is charged with gas. The principle gas used is nitrogen, which is
kept under either low pressure 10 -15 kg/cm2 or high pressures 20-30 kgcm2
OPERATION SHEET 2.1
OPERATION TITTLE:
Replace shock absorber
PURPOSE:
To obtain smooth operation of suspension system
CONDITIONS OR SITUATIONS Upon finding defective shock absorber
FOR THE OPERATION:
EQUIPMENT, TOOLS AND
MATERIALS:
Vehicle, Wheel wedge, Lift/ramp, Hand tools, new shock
absorber and bushes
PROCEDURES:
1. Collect tools and materials
2. Park the vehicle on the ramp/lift/level
ground
3. Wedge the wheels
4. Loosen the shock absorber nuts
5. Remove the shock absorber
6. Check the shock absorber operation
7. Inspect the bush
8. Replace the bush if damaged
9. Replace new shock absorber
10. Re-tighten the bolts and nuts
PRECAUTIONS:
ASSESMENT CRITERIA:





Ensure that vehicle is parked safely
Ensure that shock absorber nuts and bolts are secured
Ensure that all tools and equipment are handled properly
Defects of shock absorber is determined
Shock absorber and bushes are installed as per standard
procedures
JOB SHEET 2.1
JOB TITLE:
Replace faulty rigid suspension components
READING:
Refer manuals, information sheet and operation sheets.
OBJECTIVE:
To replace defective rigid suspension components
MATERIALS
REQUIRED:
Vehicle, Wheel wedge, , Hand tools, new shock absorber, bushes, and
Safety stand, Bench vice, Leaf springs, Centre bolt and nut, Clamp/clip and
Spring Bush
Lift/ramp and hydraulic floor jack
TOOLS &
EQUIPMENT
REQUIRED:
PROCEDURE:
ASSESSMENT
CRITERIA:
Collect required tools, materials and equipment
Park the vehicle on level ground
Replace shock absorber
Remove leaf spring assembly
Disassemble leaf spring assembly
Assembly leaf spring assembly
Refit leaf spring assembly
Change leaf spring bush
Trainer will use the following criteria during assessment:
 All operation steps were completed in the correct sequence.
 All safety precautions were followed while using the tools and
equipment.
 Defective rigid suspension components are replaced

SAMPLE OF SELF CHECK 2.1
Self Check 2.1
SECTION A: Short Answer type question
1. State the function of shock absorber
2. State types of shock absorber
3. Classify the shock absorber by it working medium and by its construction.
SECTION B: Multiple Choice question/objective type questions
1. Gas filled shock absorber is types of shock absorber which falls under
a. Rotary vane type hydraulic shock absorber
b. Cam actuated piston type hydraulic shock absorber
c. Hydraulic shock absorber
c. Mono tube shock absorber
2. All of the following are function of shock absorber except
a. Minimize Tire Wear
b. Stabilize Vehicle Tires
c. Stabilize Vehicle Ride
d. Minimize shock absorber wear
SECTION C: True/false or matching type question
State true or false for the following statement
1. Twin-tube shock absorber is type of shock absorber that is classified according to working
medium
2. Reduce Overall Suspension Wear is function of shock absorber
SECTION D: Explanation type/open ended type question
1. Label the part of the shock absorber given below
2. Differentiate between single action shock absorber and Multiple-action Shock Absorber

Model Answer 2.1
MODEL ANSWER TO A SELF-CHECK 2.1
SECTION A: Short Answer type question
1. State the function of shock absorber
Answer. The functions of shock absorber are
a. Limit Vehicle Body Movement
b. Stabilize Vehicle Ride
c. Stabilize Vehicle Tires
d. Minimize Tire Wear
e. Reduce Overall Suspension Wear
2. State types of shock absorber
Answer. Types of shock absorber are
a. Classifications by operation
 Single-action shock Absorber
 Multiple-action Shock Absorber
b. Classification by the constructions
 Twin-tube shock absorber
 Mono tube Shock absorber
c. Classification by working medium
 Hydraulic shock absorber
 Gas filled shock absorber
SECTION B: Multiple Choice question/objective type questions
1. Gas filled shock absorber is types of shock absorber which falls under
a. Rotary vane type hydraulic shock absorber
b. Cam actuated piston type hydraulic shock absorber
c. Hydraulic shock absorber
a. Mono tube shock absorber
2. All of the following are function of shock absorber except
a. Minimize Tire Wear
b. Stabilize Vehicle Tires
c. Stabilize Vehicle Ride
d. Minimize shock absorber wear
SECTION C: True/false or matching type question
State true or false for the following statement
1. Twin-tube shock absorber is type of shock absorber that is classified according to working
medium False
2. Reduce Overall Suspension Wear is function of shock absorber True
SECTION D: Explanation type/open ended type question
1. Label the part of the shock absorber given below
2. Differentiate between single action shock absorber and Multiple-action Shock Absorber
Answer.
Single-action shock Absorber
Multiple-action Shock Absorber
Damping occurs only when the shock
absorber is extended. No damping force is
generated when it is compressed.
Damping occurs both when the shock
absorber is extended and when it is
compressed. Currently, most shock absorbers
are used on cars is of this type.
Lesson 2.2: Leaf spring
LEARNING GUIDE
Learning Steps
Resources
1. Read the Information Sheet 2.2 on Types
and function of leaf spring and function Information Sheet 2.2
of leaf spring components
2. Read and Perform Skill Sheet 2.2.3: on use
of hydraulic jack and 2.2.4 on removal of Skill sheet
wheel
3. Read and Perform Operation Sheet 2.2 on Operation Sheet 2.2
remove leaf spring assembly
4. Answer Self Check 2.2
Sample Self Check 2.2
5. Compare to Model Answer 2.2
Model Answer to Self Check2.2
If finished, proceed to lesson 2.3
After completing the activities of this learning unit you should achieve the following:


State the types and function of leaf spring
Explain the function of leaf spring components
INFORMATION SHEET 2.2
2.2.1 Types and function of leaf spring
There are five types of leaf springs
1. Full – elliptic type
Two semi-elliptic springs connected to form the
shape of an ellipse. The advantage of this type is the
elimination of shackle and spring. The lubrication and
wear frequently which are one of the main
drawbacks of this type of springs.
2. Semi – elliptic type
Forming the shape of half ellipse. This type is more
popular for rear suspensions are used in 75% of cars.
3. Quarter- elliptic type
Half of the semi-elliptic spring
4. Three Quarter – elliptic type
One semi-elliptic spring connected over a quarter
elliptic springs. This type is rarely used in now-a-days.
It gives resistance, but occupies more space than
other types
5. Transverse Spring type
Semi-elliptic type spring which has the saddle at
above forming a bow and is fitted parallel to wheel
axle. This type of spring is arranged transversely
across the car instead of longitudinal direction. The
transverse spring for front axle which is bolted rigidly
to the frame at the center and attached to the axle
by means of shackle at both ends
Function of leaf spring
Leaf springs are bend blades of spring steel that can flex freely. Lightening shocks is not the only function of leaf
springs, but also serving as arms to support the axle. For this reason, leaf springs are stiffer, and provide a rougher
ride. However, they have simple structure and strength.
Helper spring: Helper springs are used in the vehicles to provide additional support for heavy loads.
These are both leaf as well as coil spring types. Either type is used in conjunction with regular
suspension system of either type.
In trucks and many other vehicles which undergo great fluctuations in their loads, helper springs are
used. The helper spring is installed above the main spring operates, but when the load exceeds certain
value, both the main and helper spring come into operation.
2.2.2 Function of leaf spring components
1. Leaf: Leaf spring consists of a number of leaves, made of steel plates, of increasing lengths from
the centre.
2. Spring Shackles: Shackles are sort of links by means of which leaf spring are connected with the
chassis frame. The shackles provide swinging ability to the leaf springs. Due to shock on the road
wheel, the spring flattens up and increases in length and during rebound the spring assumes back
its shape thereby decreasing in length. The shackle makes the springs worthy to swing in and out.
Shackle compensate the change in length of the spring
3. Rubber bushings/bush: it absorbs vibrations and prevents it from reaching the body and allows
the spring eyes to twist back and forth as the leaf springs bend.
4. Bumpers: The springs sometimes contract and expand more than permitted and can cause
damage to other components when the wheels goes over a large bump or hole. The bounding
bumpers protect the frame, axles, shock absorber, etc when the springs compresses and expand
more than permitted.
5. U-bolt: It attaches by two U bolts and is placed either over or under the axle housing.
6. Rebound clip: A metal cover or rebound clips placed along the spring keep the leaves in
alignment. They also prevent excessive leaf separation during rebound.
7. Hanger pin: One end of the leaf spring is fixed to the frame by hanger at front
8. Centre bolt: The center bolt keeps the leaf spring in place so when the u bolts are properly torque
the leaf spring center bolt will stay fastened to the axle seat.
SKILL SHEET 2.2.3
SKILL TITLE:
Use of hydraulic jack
EQUIPMENT, TOOLS AND
MATERIALS:
Hydraulic jack
PROCEDURE:
1. Park the vehicle on level ground
LIFTING
2. Turn the release screw counterclockwise to lower the jack. Once the jack is fully lowered, turn the
screw firmly clockwise to close it.
3. Carefully position the saddle of the jack (see photo above) under the vehicle manufacturer’s
recommended lifting point.
4. Pump the handle until the top of the jack’s saddle has nearly reached the vehicle lifting point.
Note: the jack should be positioned at 90° to the vehicle’s lifting point to ensure the jack’s saddle
and vehicle lifting point are in alignment. If not, reposition the jack before lifting the vehicle.
5. To lift the vehicle, pump the handle of the jack. Use smooth, full strokes for best results.
6. Once the vehicle is raised, slide a safety stand of appropriate capacity (not included) under the
proper lifting point referred to in the vehicle owner’s manual. If using two safety stands, position
them at the same point/height on each side of the vehicle.
7. Slowly turn the release screw counterclockwise to lower the vehicle onto the saddle(s) of the safety
stand(s). Then, turn the valve release screw firmly clockwise to close it.
8. While standing safely aside, gently rock the vehicle to determine if it is stable on the jack stand(s).
If it is not, raise the vehicle, and reposition the safety stand(s).
LOWERING
1. Remove all tools, parts, etc. from under the vehicle.
2. Position the saddle under the lifting point. Turn the release screw firmly clockwise, and pump the
handle to raise the vehicle slightly above the saddle(s) of the jack stands. Then, lower the saddle to
its lowest position and remove jack stand(s).
3. Slowly turn the handle counterclockwise (never more than two full turns) to lower the vehicle onto
the ground.
4. Lower the jack completely. then, store in a safe place or location
SKILL SHEET 2.2.4
SKILL TITLE:
Remove wheel
EQUIPMENT, TOOLS AND
MATERIALS:
Hydraulic jack, safety stand. Lever, wheel wrench
PROCEDURE:
1. Park the vehicle on the level ground
2. Wedge the vehicle
3. Loosen the wheel nuts partially
4. Jack up the vehicle
5. Support the axle with the help of steel hose stands
6. Remove the wheel nuts
7. Remove the wheel with help of lever
8. Follow the reverse procedure to refit the wheel
OPERATION SHEET 2.2
OPERATION TITLE:
Remove leaf spring assembly
PURPOSE:
To change/ leaf spring components
CONDITIONS OR SITUATIONS
FOR THE OPERATION:
Upon finding defective leaf spring components
EQUIPMENT, TOOLS AND
MATERIALS:
Vehicle, Wheel wedge, Hand tools, hydraulic floor jack and Safety
stand
PROCEDURE:
1. Support the chassis and axle by safety
stand
2. Remove the wheel
3. Remove the shock absorber
4. Lower the axle until the leaf spring
tension is free
5. Remove the U-bolts, spring seat and
spring bumper
6. Remove the shackle assembly
7. Remove hanger pin
8. Remove the leaf spring assembly
PRECAUTIONS:
 Ensure that vehicle is parked safely
 Ensure that chassis and axel is supported by safety stand
ASSESSMENT CRITERIA:
 Leaf spring is removed without damaging other parts

SAMPLE OF SELF CHECK 2.2
Self Check 2.2
SECTION A: Short Answer type question
1. List down the types of leaf spring
2. State the function of leaf spring
SECTION B: Multiple Choice question/objective type questions
1. Elimination of shackle and spring is the advantage of
a. Full – elliptic type
b. Semi – elliptic type
c. Quarter- elliptic type
d. Three Quarter – elliptic type
2. The function of shackle with a leaf spring is to:
a. allow pivoting of spring end
b. allow spring length to change
c. control sides way
d. control rear torque
SECTION C: True/false or matching type question
State true or false for the following statement
1. Helper springs are used in the vehicles to provide additional support for heavy loads.
2. Spring bumper absorbs vibrations and prevents it from reaching the body and allows the spring
eyes to twist back and forth as the leaf springs bend
SECTION D: Explanation type/open ended type question
1. Label the diagram given below

Model Answer 2.2
MODEL ANSWER TO A SELF-CHECK 2.2
SECTION A: Short Answer type question
1. List down the types of leaf spring
Answer. Types of leaf spring are
a. Full – elliptic type
b. Semi – elliptic type
c. Quarter- elliptic type
d. Three Quarter – elliptic type
e. Transverse Spring type
2. State the function of leaf spring
Answer. The functions of leaf spring are lightening shocks and serve as arms to support the axle
SECTION B: Multiple Choice question/objective type questions
1. Elimination of shackle and spring is the advantage of
a. Full – elliptic type
b. Semi – elliptic type
c. Quarter- elliptic type
d. Three Quarter – elliptic type
2. The function of shackle with a leaf spring is to:
a. allow pivoting of spring end
b. allow spring length to change
c. control sides way
d. control rear torque
SECTION C: True/false or matching type question
State true or false for the following statement
1. Helper springs are used in the vehicles to provide additional support for heavy loads. True
2. Spring bumper absorbs vibrations and prevents it from reaching the body and allows the spring
eyes to twist back and forth as the leaf springs bend. False
SECTION D: Explanation type/open ended type question
2. Label the diagram given below
Lesson 2.3: Leaf spring
LEARNING GUIDE
Learning Steps
Resources
1. Read the Information Sheet 2.3 on
Information Sheet 2.3
material of leaf spring and spring defects
2. Read and Perform Operation Sheet 2.3 on Operation Sheet 2.3
disassemble leaf spring assembly
If finished, proceed to lesson 2.4
INFORMATION SHEET 2.3
2.3.1
Materials of spring
The suitable steels that have been used for the leaf springs are given below
1. Chrome-vanadium steel
Constituents
C
Mn
Si
Ni
Cr
Va
2. Silico- Manganeses Steel
Constituents
C
Mn
Si
Cr
3. Carbon Steel
Constituents
C
Mn
Si
2.3.2
Percentage
0.46
0.57
0.17
0.15
1.40
0.18
Percentage
0.52
1.05
1.95
0.05
Percentage
0.55
0.60
0.20
Spring defects
a. The condition of spring leaves: a cracked or fractured leaf, or one which has been repaired by
welding or is permanently distorted due to damage or so deteriorated that it is seriously
weakened.
b. The condition of spring eyes: a defective spring eye
c. The correct location of the springs to the axle for symmetry: a spring so fitted that the axle is
misaligned
d. A shackle and hanger pin not correctly positioned or excessively loose in its bracket
e. Excessive side play at spring eye.
f. Check the security of spring and saddle to the axle
 Evidence that a spring saddle is fractured or moving relative to the spring
 A nut or bolt securing the spring to the axle not secure or missing
OPERATION SHEET 2.3
OPERATION TITLE:
Disassemble leaf spring assembly
PURPOSE:
To replace leaf spring components
CONDITIONS OR SITUATIONS
FOR THE OPERATION:
Upon finding defective leaf spring components
EQUIPMENT, TOOLS AND
MATERIALS:
Hand tools and Bench vice
PROCEDURE:
1. Clamp the leaf spring assembly on the
bench vice
2. Pry up the leaf spring clamp
3. Loosen the centre bolt nut
4. Remove the spring
5. Inspect the leaf spring for damage
6. Remove the spring bush
7. Determine the leaf spring for damage
PRECAUTIONS:
 Ensure that leaf spring assembly is clamped on the vice securely
ASSESSMENT CRITERIA:
 Leaf spring assembly is clamped on the vice securely
 Damage of leaf spring is determined
Lesson 2.4: Leaf spring
OPERATION SHEET 2.4
OPERATION TITLE:
Assemble leaf spring assembly
PURPOSE:
To replace leaf spring components
CONDITIONS OR SITUATIONS
FOR THE OPERATION:
After replacing defective leaf spring components
EQUIPMENT, TOOLS AND
MATERIALS:
Hand tools, Bench vice, Leaf springs, Centre bolt and nut,
Clamp/clip and Spring Bush
PROCEDURE:
1. Replace leaf spring, centre bolt and nut,
clamp if damaged
2. Arrange the leaf springs in sequential
order
3. Insert the centre bolt
4. Clamp the leaf spring assembly on the
bench vice
5. Install and tighten the centre bolt nut
6. Bend the spring clamps
7. Remove the leaf spring assembly from
the bench vice
8. Install the leaf spring bushes
PRECAUTIONS:
Ensure that leaf spring assembly is clamped on the vice securely
ASSESSMENT CRITERIA:
 Leaf spring assembly is assembled as per standard procedures
Lesson 2.5: Leaf spring
SKILL SHEET 2.5
SKILL TITLE:
Use of torque wrench
EQUIPMENT, TOOLS AND
MATERIALS:
PROCEDURE:
1. Examine the torque wrench.
2.
3.
4.
5.
Determine the nut and bolt that you wish to tighten.
Consider the dial and set it according to the size and diameter of the nut and bolt.
Fix the appropriate socket of the wrench on to the nut or bolt and then slowly begin the tightening process.
Make sure that you use short and equally spaced strokes.
Stop tightening when the wrench feels like it "breaks" or slips on the nut. When the appropriate pressure is
gained, the mechanism inside the wrench cuts off the force that is being applied by the user.
OPERATION SHEET 2.5
OPERATION TITLE:
Refit leaf spring assembly
PURPOSE:
To replace or repair leaf spring components
CONDITIONS OR SITUATIONS
FOR THE OPERATION:
After replacing or repairing defective leaf spring components
EQUIPMENT, TOOLS AND
MATERIALS:
Hand tools, Lever, hydraulic floor Jack and safety stand
PROCEDURE:
1. Install the leaf spring assembly in the spring
hanger
2. Install the hanger pin and nut
3. Install the spring shackle and bush on the
chassis
4. Install the other end of leaf spring assembly
in the spring shackle
5. Install the shackle plate and nuts
6. Tighten the hanger nuts
7. Jack up the axel and align centre bolt head
8. Install the spring bumper
9. Install “U” bolts and spring seat
10. Tighten the “U” bolt
11. Install shock absorber
12. Refit the wheel
13. Remove the safety stands
PRECAUTIONS:
 Ensure that leaf spring assembly is clamped on the vice securely
ASSESSMENT CRITERIA:
 Leaf spring assembly is refitted as per standard procedures
 ‘U’ bolts are tightened as per standard practice
Lesson 2.6 Leaf spring
OPERATION SHEET 2.6
OPERATION TITLE:
Change leaf spring bush
PURPOSE:
To replace with new bush
CONDITIONS OR SITUATIONS
FOR THE OPERATION:
Upon finding worn out bush
EQUIPMENT, TOOLS AND
MATERIALS:
Hand tools, Pry bar, Jack, Safety stand, Spring bush and MP grease
PROCEDURE:
1. Support the chassis by safety stand
2. Lower the axle until the leaf spring tension
is free
3. Remove the shackle pin’s nuts and plate
4. Remove the spring eye by lever from
shackle pin
5. Remove the spring bushes
6. Replace the new spring bushes
7. Insert the spring on the spring shackle
8. Install shackle plate and nuts
9. Remove the hanger pin
10. Pry up spring eye by lever
11. Remove spring bushes
12. Replace new spring bushes
13. Insert spring eye on hanger
14. Install hanger pin and nut
15. Remove safety stands
PRECAUTIONS:
 Ensure that damaged spring bushes and old grease are disposed in proper place
 Ensure that safety stands are properly positioned
ASSESSMENT CRITERIA:
 Spring bushes are changed as per industrial procedures
 Nuts and bolts are tightened as per standard practice
 Damaged bushes are replaced
Reference

H.crouse, W. (1974). Automotive Mechanics. Austrialia .

H.Gerschler. (n.d.). Technology for the automotive trade Volume 1. In H.Gerschler, Technology
for the automotive trade Volume 1.

SIMPSON, E. M. (2007). Automotive Mechanics. In E. M. SIMPSON, Automotive Mechanics.
Australia: McGraw-Hill Australia.

Singh, D. K. (2008). In D. K. Singh, Automobile Engineering Vol.1. Delhi.
CHAPTER 17
Change antilock brake system speed sensors
Lesson 17.1: Antilock brake system speed sensors
LEARNING GUIDE
Learning Steps
1. Read the Information Sheet 2.14: on
definition of ABS system, components
of ABS, function of ABS and operation
of ABS.
Resources
Information Sheet 2.14
2. Read and Perform Operation Sheet
2.14: on changing load sensing device
Operation Sheet 2.14
3. Answer Self Check 2.14
Sample Self Check 2.14
4. Compare to Model Answer 2.14
Model Answer to Self Check 2.14
If finished, proceed to lesson 2.15
After completing the activities of this learning unit you should achieve the following:





Define ABS system
Describe the components of ABS
State the function of ABS
Explain the operation of ABS system.
Know the procedure for changing speed sensors.
INFORMATION SHEET 2.14
1.14.1 Definition of ABS system
A braking system in which a sensor recognizes that a wheel is about to be locked up. The sensor
sends a message to a computer, which starts releasing and applying the brake, stopping the lock
up and allowing the driver to maintain control or drive around an obstacle instead of sliding
towards it.
1.14.2 Components of ABS
The following layout shows the basic components of antilock braking system:
1. Electronic control unit
(ECU)
2. Hydraulic control unit or
modulator
3. Wheel sensor unit
4. Power booster & master
cylinder assembly
1. Electronic control unit (ECU)
The ECU is located inside the vehicle. It receives
signals from the sensors in the circuit and controls the
brake pressure at the road wheel according to the data
analyzed by the Unit
2. Hydraulic control unit or modulator
The location of the Hydraulic Control Unit, or Modulator,
varies from manufacturer to manufacturer. Some locate it
under the fender or hood.
It receives operating signals from the ECU to apply or release
the brakes under ABS conditions
3. Wheel sensor unit
The wheel sensor unit consists of a tooth rotor that rotates
with the road wheels and a pick-up that is located in the
wheel hub.
4. Power booster & master cylinder assembly
The power booster and master cylinder assembly is
mounted on the firewall and is activated when the driver
pushes down on the brake pedal. It provides the power
assistance required during braking.
1.14.3 Function of sensors
The main function of sensor is to monitor the wheel speed and send signal to ECU to activate the
ABS.
1.14.4 Operation of ABS system
Applying brakes too hard, or on a slippery surface, can cause the wheels to lock, steering control
is lost and, in most cases, it produces longer stopping distances. The antilock braking system
prevents wheels locking or skidding, no matter how hard brakes are applied, or how slippery the
road surface. Steering stays under control and stopping distance are generally reduced.
The wheel speed sensor consists of a notched or toothed rotor that rotates with each wheel, and a
pickup. As the wheel turns, a small voltage pulses is induced into the pickup and sent to the
electronic control unit. When the brakes are applied the wheel’s speed of rotation changes. This
sends a new signal to the ECU.
If the control unit detects that a wheel might lock, it sends a signal to the hydraulic control unit
and the hydraulic control unit uses solenoid valves to control the brake pressure and to prevent
the wheel from getting lock.
OPERATION SHEET 2.14
OPERATION TITLE:
Change anti lock brake system speed sensor
PURPOSE:

Make the braking system effective.
CONDITIONS OR SITUATIONS
FOR THE OPERATION:

When a sensors does not function
EQUIPMENT, TOOLS AND
MATERIALS:





Hand tools
wheel speed sensor
wheel wedge
Stands
Jack
PROCEDURE:
1.
2.
3.
4.
Wedge the wheels
Jack up and support the vehicle
Detach the wire connector from the sensor
Take note of the exact placement and routing of the
wiring and remove any clips, grommets and
retainers necessary to free the wire
5. Remove the sensor mounting bolt
6. Remove the sensor
7. Install the new wheel speed sensor
8. Tighten the sensor mounting bolt
9. Connect the wire connector to the sensor
10. Route the wiring and install any clips, grommets
and retainers
11. Remove the safety stand, jack and wheel wedge
12. Drive the vehicle for ON TEST
PRECAUTIONS:

Ensuring that wire is routed as previously to avoid crimping or twisting the wire or harness
ASSESSMENT CRITERIA:
 ABS wheel speed sensor is replaced as per standard procedures
 Sensor wire connector is connected as per standard practice

SAMPLE OF SELF CHECK 2.14
Self Check 2.14
SECTION A: Short Answer type question/complete type question
1. Define ABS
2. State the function of ABS
3. Explain the operation of ABS

MODEL ANSWER TO A SELF-CHECK 2.14
Model Answer 2.14
Section A
1. A braking system in which a sensor recognizes that a wheel is about to be locked up. The
sensor sends a message to a computer, which starts releasing and applying the brake,
stopping the lock up and allowing the driver to maintain control or drive around an obstacle
instead of sliding towards it.
2. The main function of sensor is to monitor the wheel speed and send signal to ECU to activate
the ABS.
3. Applying brakes too hard, or on a slippery surface, can cause the wheels to lock, steering
control is lost and, in most cases, it produces longer stopping distances. The antilock braking
system prevents wheels locking or skidding, no matter how hard brakes are applied, or how
slippery the road surface. Steering stays under control and stopping distance are generally
reduced.
The wheel speed sensor consists of a notched or toothed rotor that rotates with each wheel,
and a pickup. As the wheel turns, a small voltage pulses is induced into the pickup and sent
to the electronic control unit. When the brakes are applied the wheel’s speed of rotation
changes. This sends a new signal to the ECU.
If the control unit detects that a wheel might lock, it sends a signal to the hydraulic control
unit and the hydraulic control unit uses solenoid valves to control the brake pressure and to
prevent the wheel from getting lock.
CHAPTER 5
Change brake booster
Lesson 5.1.Change brake booster
LEARNING GUIDE
Learning Steps
Resources
1. Read the Information Sheet
Information Sheet 5.1
2. Read and Perform Skill Sheet 5.1: on …..
Skill sheet5.1
3. Read and Perform Operation Sheet 5.1:
on …..
Operation Sheet 5.1
4. Read and Perform Job Sheet 5.1: On …
Job Sheet 5.1
5. Answer Self Check 5.1
Sample Self Check 5.1
6. Compare to Model Answer 5.1
Model Answer to Self Check 5.1
If finished, proceed to lesson 1.2
After completing the activities of this learning unit you should achieve the following:
INFORMATION SHEET 5.1
SKILL SHEET 5.1
SKILL TITLE:
EQUIPMENT, TOOLS AND
MATERIALS:
PROCEDURE:
OPERATION SHEET 5.1
OPERATION TITLE:
Change brake booster
PURPOSE:
Brake booster problems can be really dangerous. A few
common problems that are difficult to detect, but
commonly occur include the following. Hold the brake
pedal down and start the engine. The brake pedal will
pull down slightly when the engine starts. If this does
not happen, it indicates a problem with the car vacuum.
Vacuum or fluid leaks from the booster are possible due
to worn out or damaged pistons, valves and hoses. There
is a large internal diaphragm that creates the vacuum for
the brake. It can harden with time, and this can cause
brake to harden and be difficult to press down.
CONDITIONS OR SITUATIONS
FOR THE OPERATION:
When the following symptoms are observed:
EQUIPMENT, TOOLS AND
MATERIALS:
Mechanic hand tools set, Rag, Booster


Hard brake pedal
Vacuum leak. Either on the rubber line that runs
from the booster to the engine
PROCEDURE:
1. Remove the brake master cylinder
2. Disconnect the vacuum warning switch connector
3. Remove the vacuum switch and grommet from the booster
4. Slide the clip and disconnect the hose
5. Remove the check valve and grommet from the booster
6. Remove the return spring ,clip and clevis pin
7. Loosen the push rod clevis lock nut
8. Remove the nuts and push rod clevis
9. Remove the booster and gasket
10. Install new gasket to the new brake booster
11. Refit the brake booster in the reverse order of removal
PRECAUTIONS:

Ensure brake booster components are removed safely
ASSESSMENT CRITERIA:


Brake booster is changed as per standard procedures
Components are disconnected without damage
JOB SHEET 5.1
JOB TITLE:
Change brake booster
READING:
Service manual, information sheet and operation sheets.
OBJECTIVE:
Change brake booster according to periodic maintenance.
MATERIALS
REQUIRED:
Rag, Booster
TOOLS &
EQUIPMENT
REQUIRED:
Mechanic hand tools set
1.
2.
3.
4.
5.
Park the vehicle on the ramp or on the level ground
Issue the brake booster from store
Change brake booster (Refer the repair manual)
Check booster for air tightness
Analyze the test results
6. Follow safety precautions
PROCEDURE:
ASSESSMENT
CRITERIA:
Trainer will use the following criteria during assessment:


Brake booster is changed as per standard procedures
Components are disconnected without damage

SAMPLE OF SELF CHECK 2.3
Self Check 1.1
SECTION A: Short Answer type question
SECTION B: Multiple Choice question/objective type question
SECTION C: True/false or matching type question
SECTION D: Explanation type/open ended type question

Model Answer 1.1
Section A
Section B
Section C
Section D
MODEL ANSWER TO A SELF-CHECK 2.3
CHAPTER 5
Change brake booster
Lesson 5.1.Change brake booster
LEARNING GUIDE
Learning Steps
Resources
1. Read the Information Sheet
Information Sheet 5.1
2. Read and Perform Skill Sheet 5.1: on …..
Skill sheet5.1
3. Read and Perform Operation Sheet 5.1:
on …..
Operation Sheet 5.1
4. Read and Perform Job Sheet 5.1: On …
Job Sheet 5.1
5. Answer Self Check 5.1
Sample Self Check 5.1
6. Compare to Model Answer 5.1
Model Answer to Self Check 5.1
If finished, proceed to lesson 1.2
After completing the activities of this learning unit you should achieve the following:
INFORMATION SHEET 5.1
SKILL SHEET 5.1
SKILL TITLE:
EQUIPMENT, TOOLS AND
MATERIALS:
PROCEDURE:
OPERATION SHEET 5.1
OPERATION TITLE:
Change brake booster
PURPOSE:
Brake booster problems can be really dangerous. A few
common problems that are difficult to detect, but
commonly occur include the following. Hold the brake
pedal down and start the engine. The brake pedal will
pull down slightly when the engine starts. If this does
not happen, it indicates a problem with the car vacuum.
Vacuum or fluid leaks from the booster are possible due
to worn out or damaged pistons, valves and hoses. There
is a large internal diaphragm that creates the vacuum for
the brake. It can harden with time, and this can cause
brake to harden and be difficult to press down.
CONDITIONS OR SITUATIONS
FOR THE OPERATION:
When the following symptoms are observed:
EQUIPMENT, TOOLS AND
MATERIALS:
Mechanic hand tools set, Rag, Booster


Hard brake pedal
Vacuum leak. Either on the rubber line that runs
from the booster to the engine
PROCEDURE:
1. Remove the brake master cylinder
2. Disconnect the vacuum warning switch connector
3. Remove the vacuum switch and grommet from the booster
4. Slide the clip and disconnect the hose
5. Remove the check valve and grommet from the booster
6. Remove the return spring ,clip and clevis pin
7. Loosen the push rod clevis lock nut
8. Remove the nuts and push rod clevis
9. Remove the booster and gasket
10. Install new gasket to the new brake booster
11. Refit the brake booster in the reverse order of removal
PRECAUTIONS:

Ensure brake booster components are removed safely
ASSESSMENT CRITERIA:


Brake booster is changed as per standard procedures
Components are disconnected without damage
JOB SHEET 5.1
JOB TITLE:
Change brake booster
READING:
Service manual, information sheet and operation sheets.
OBJECTIVE:
Change brake booster according to periodic maintenance.
MATERIALS
REQUIRED:
Rag, Booster
TOOLS &
EQUIPMENT
REQUIRED:
Mechanic hand tools set
1.
2.
3.
4.
5.
Park the vehicle on the ramp or on the level ground
Issue the brake booster from store
Change brake booster (Refer the repair manual)
Check booster for air tightness
Analyze the test results
6. Follow safety precautions
PROCEDURE:
ASSESSMENT
CRITERIA:
Trainer will use the following criteria during assessment:


Brake booster is changed as per standard procedures
Components are disconnected without damage

SAMPLE OF SELF CHECK 2.3
Self Check 1.1
SECTION A: Short Answer type question
SECTION B: Multiple Choice question/objective type question
SECTION C: True/false or matching type question
SECTION D: Explanation type/open ended type question

Model Answer 1.1
Section A
Section B
Section C
Section D
MODEL ANSWER TO A SELF-CHECK 2.3
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