SDA-1200, SDA-1400 & SDA
SERVICE MANUAL
SDA-1200 STEERABLE DRIVE AXLE
SDA-1400 STEERABLE DRIVE AXLE
SDA-1600 STEERABLE DRIVE AXLE
WITH EXTENDED SERVICE BRAKES
AND ABS PROVISIONS
Fabco Automotive Corporation, Livermore, CA
VP 9/03
Ph: (925) 454-9500
1- (800) 967- 8838
Fax (925) 454-9501 www.fabcoautomotive.com
TABLE OF CONTENTS
PAGE
1.0
2.0
3.0
INTRODUCTION ...............................................................................................................................
1
1.1
1.2
1.3
1.4
1.5
1.6
1
1
1
2
2A
2B
LUBRICATION ..................................................................................................................................
3
2.1
2.2
2.3
2.4
2.5
2.6
Wheel Bearings·····················································································································
Universal Joints·····················································································································
Kingpin Bearings···················································································································
Differential Carrier·················································································································
Steering Tie Rod Ends··········································································································
Spindle Inner Bearings··········································································································
3
3
3
3
3
3
AXLE ADJUSTMENT........................................................................................................................
4
3.1
3.2
3.3
3.4
3.5
3.6
3.7
3.8
3.9
4.0
General ·································································································································
Wheel Bearing Adjustment ···································································································
Kingpin Adjustment ···············································································································
Toe-in Adjustment·················································································································
Steering Stop Adjustment ·····································································································
Camber Adjustment ··············································································································
Caster Adjustment ················································································································
Brake Adjustment··················································································································
Universal Joint Adjustment ···································································································
4
4
4-5
5
6
6
6
6
6-7
STEERABLE DRIVE END DISASSEMBLY......................................................................................
7
4.1
4.2
4.3
4.4
5.0
6.0
General Description ··············································································································
Operation ······························································································································
Operating Instructions···········································································································
SDA-1200 Specifications ······································································································
SDA-1400 Specifications ······································································································
SDA-1600 Specifications ······································································································
General Precautions for Disassembly···················································································
Brake Drum, Hub, and Wheel Bearings················································································
Brake and Wheel Spindle ·····································································································
Splindle Yoke Removal·········································································································
7
7-8
8-9
9-10
CLEANING AND INSPECTION ........................................................................................................
10
5.1
5.2
5.3
Choice of Cleaning Methods·································································································
Drying and Corrosion Inhibition·····························································································
Inspection······························································································································
10
10
10
STEERABLE DRIVE END ASSEMBLY............................................................................................
10
General Precautions for Assembly ·······················································································
Spindle Installation················································································································
Brake Equipment ··················································································································
Wheel Bearings, Hub, and Brake Drum················································································
10
11-12
12-13
13
6.1
6.2
6.3
6.4
TABLE OF CONTENTS
PAGE
7.0
ADDITIONAL SERVICE PROCEDURES..........................................................................................
14
7.1
7.2
Steerable Drive End Removal·······························································································
Differential Carrier Removal··································································································
14
15
8.0
TORQUE SPECIFICATIONS ............................................................................................................
16
9.0
SPECIAL TOOLS ..............................................................................................................................
17
9.1
9.2
9.3
9.4
9.5
9.6
9.7
9.8A
9.8A
9.8B
9.9
17
18
19
20
21
22
23
24
24
25
26
10.0
ABS PARTS & SERVICE.................................................................................................................. ABS-1
10.1
10.2
10.3
10.4
11.0
Spindle Seal Driver ···············································································································
Hub Seal Driver·····················································································································
Lower Kingpin Seal Driver ····································································································
Upper Kingpin Seal Driver ····································································································
Axle Seal Driver ····················································································································
Lower Kingpin Locknut Wrench ····························································································
Upper Kingpin Ball Stud Puller······························································································
Differential Carrier Removal Tool – SDA-1200 & 1400·························································
Differential Carrier Removal Tool – SDA-1600 ·····································································
Steerable End Adapter··········································································································
Inner Spindle Greasing Tool ·································································································
ABS Sensor Removal ···········································································································
ABS Sensor Inspection ·········································································································
ABS Sensor Installation ········································································································
ABS Sensor Operational Test·······························································································
Figure 10.1: ABS Assembly, Left-hand Side········································································
Figure 10.2: Clamp Assembly, ABS Cable Inside Steerable End········································
Figure 10.3: Bracket Assembly, ABS Cable, Left-hand Side ···············································
ABS-1
ABS-1
ABS-1
ABS-1
ABS-2
ABS-3
ABS-3
ILLUSTRATED PARTS.....................................................................................................................
IP-1
11.1
11.2
SDA-1200, 1400 & 1600 IIlustrated Parts·············································································
SDA-1200, 1400 & 1600 Illustrated Parts List ······································································
Copyright © 1999
IP-1
IP-2-6
Fabco Automotive Corporation, 151 Lawrence Drive, Livermore, CA 94551
ASBESTOS WARNING
SUGGESTED PROCEDURES FOR WORKING WITH COMPONENTS
SUSPECTED OF CONTAINING ASBESTOS
Asbestos has been found to be a primary cause of various forms of respiratory disease and cancer of several vital body organs. Primary ingestion is by breathing or
swallowing airborne dust containing fibers. Smokers are at a greater risk than those
who do not smoke. The onset of such a fatal disease can be at an extended period of
time, (several years) after the exposure. The Occupational and Safety Health Administration (OSHA) has established very stringent limitations for exposure to asbestos fibers by workers using the material, and every precaution should be taken to
minimize the risks involved. The following are some suggested procedures to adopt
when working with material that has, or may be suspected of containing, asbestos.
1. Approved protective clothing, gloves, eye shield and aprons should be worn
whenever working around the suspected material. NIOSH & OSHA approved
respirator masks suitable for asbestos dust should be worn at all times. Disposable dust face masks are not allowed by OSHA.
2. Do not smoke while working on any asbestos related material or wearing protective apparel.
3. Do not eat or drink food while wearing protective clothing. Always wash before
eating, drinking or smoking.
4. Do not use compressed air for any dirt removal. Use only approved high efficiency vacuum cleaners suitable for use with asbestos. Do not dry brush deposits or accumulations of dirt from components. What cannot be removed with the
high efficiency vacuum cleaner should be washed with a water soaked rag. The
rag should not be wrung dry but should be disposed of, together with other wastes
containing asbestos in specially sealed and marked containers in accordance
with EPA and OSHA regulations.
5. Do not wear protective clothing away from the working area, vacuum clean clothing before removal. Shower, if possible, before going home.
These suggestions are neither complete nor authoritative on the subject of
working with asbestos but are meant as a warning of the possible risks. It is
the responsibility of the supervising authority to be aware of the possible
dangers involved and to provide suitable training, precaution and protection for those working in an asbestos environment.
1.0 INTRODUCTION
1.1 GENERAL DESCRIPTION
The Fabco Steerable Drive Axle consists of four major
assemblies; the axle housing, two steerable drive ends,
and a differential carrier. A steering tie rod links the right
and left steerable ends, and steering input is delivered via
a steering arm. The arm is usually located on the left
steerable end, although right hand or even dual steering
arms are available.
When steered, the outer section of each steerable drive
end rotates about the kingpin centerline. The U-joint,
centered on the kingpin centerline, allows power to be
transmitted throughout the possible range of steering inputs.
The axle is equipped with S--cam air brakes and automatic slack adjusters.
1.2 OPERATION
1.3 OPERATING INSTRUCTIONS
Driving forces are put into the axle at the pinion yoke on
the differential carrier; they pass through the differential
to the inner axle shafts and on to the universal joints. The
yoke shafts get their power from the U-joints and transfer
it by means of splines to the drive flanges, which are
bolted to the wheel hubs, thus rotating the wheels.
In conditions where the vehicle's rear wheels might spin,
such as sand, loose dirt, mud, snow, ice, or ascending
grades, the front drive axle can be shifted into operation
for improved traction. Engagement can be made at any
vehicle speed, provided that the rear wheels are not spinning. Engagement is best accomplished when the engine is pulling lightly.
– 1–
1.4 STEERABLE DRIVE AXLE SPECIFICATIONS — FABCO MODEL SDA-1200
MAXIMUM CAPACITY
12,000 Pounds Load Rating
BRAKES
Type
Size
Chamber
Certification
Slack Adjusters
Drum, S-Cam
16.5 Diameter x 5 Inch
20 Square Inch
FMVSS 121
Automatic
HOUSING
Fabricated Steel, Cast Banjo
CAMBER
1/2° Positive
WHEELS
Mounting
Minimum Wheel Size
DIFFERENTIAL CARRIER
Ring Gear Diameter
Pinion Spline
Single Reduction Ratios
UNIVERSAL JOINT
10-Studs on 11.25 Inch Bolt Circle
20 Inch
Hypoid
13.4 Inch
1.75 Diameter, 34 Spline Involute
3.55, 3.70, 3.90, 4.11, 4.33, 4.63, 4.88,
5.29, 5.38, 5.57, 5.83, 6.17, 6.50, 7.17
Single Cardan
KINGPINS
Type
Inclination
Spherical
5°
STEERING
Ackerman to Match Wheelbases
146" to 183" or 184" to 222"
TRACK
91.1 Inches over Wheel Mounting Faces
AXLE SHAFTS
Spline
Body
TURN ANGLE
1.75 Inch Diameter, 34 Spline Involute
1.69 Inch Diameter
35°
LUBRICATION
Type
Capacity
WEIGHT – Dry
SAE 90, 140, 80W-140, Synthetic Acceptable
Approximately 9.5 Quarts
1,435 Lbs.
–2–
1.5 STEERABLE DRIVE AXLE SPECIFICATIONS — FABCO MODEL SDA-1400
MAXIMUM CAPACITY
14,000 Pounds Load Rating
BRAKES
Type
Size
Chamber
Certification
Slack Adjusters
Drum, S-Cam
16.5 Diameter x 5 Inch
20 Square Inch
FMVSS 121
Automatic
HOUSING
Fabricated Steel, Cast Banjo
CAMBER
1/2° Positive
WHEELS
Mounting
Minimum Wheel Size
DIFFERENTIAL CARRIER
Ring Gear Diameter
Pinion Spline
Single Reduction Ratios
UNIVERSAL JOINT
10-Studs on 11.25 Inch Bolt Circle
20 Inch
Hypoid
13.4 Inch
1.75 Diameter, 34 Spline Involute
3.55, 3.70, 3.90, 4.11, 4.33, 4.63, 4.88,
5.29, 5.38, 5.57, 5,83, 6.17, 6.50, 7.17
Single Cardan
KINGPINS
Type
Inclination
Spherical
5°
STEERING
Ackerman to Match Wheelbases
146" to 183" or 184" to 222"
Dual Steering Arms
TRACK
91.1 Inches over Wheel Mounting Faces
AXLE SHAFTS
Spline
Body
TURN ANGLE
1.75 Inch Diameter, 34 Spline Involute
1.69 Inch Diameter
35°
LUBRICATION
Type
Capacity
WEIGHT – Dry
SAE 90, 140, 80W-140, Synthetic Acceptable
Approximately 9.5 Quarts
1,455 Lbs.
– 2A –
1.6 STEERABLE DRIVE AXLE SPECIFICATIONS — FABCO MODEL SDA-1600
MAXIMUM CAPACITY
16,000 Pounds Load Rating
BRAKES
Type
Size
Chamber
Certification
Slack Adjusters
Drum, S-Cam
16.5 Diameter x 6 Inch
24 Square Inch
FMVSS 121
Automatic
HOUSING
Fabricated Steel, Cast Banjo
CAMBER
1/2° Positive
WHEELS
Mounting
Minimum Wheel Size
DIFFERENTIAL CARRIER
Ring Gear Diameter
Pinion Spline
Single Reduction Ratios
UNIVERSAL JOINT
10-Studs on 11.25 Inch Bolt Circle
20 Inch
Hypoid
14.5 Inch
1.75 Diameter, 34 Spline Involute
3.55, 3.70, 3.90, 4.11, 4.33, 4.63, 4.88,
5.29, 5.38, 5.57, 5.83, 6.17, 6.50, 7.17
Single Cardan
KINGPINS
Type
Inclination
Spherical
5°
STEERING
Ackerman to Match Wheelbases
146" to 183" or 184" to 226"
Dual Steering Arms
TRACK
91.1 Inches over Wheel Mounting Faces
AXLE SHAFTS
Spline
Body
TURN ANGLE
1.85 Inch Diameter, 36 Spline Involute
1.69 Inch Diameter
35°
LUBRICATION
Type
Capacity
WEIGHT – Dry
SAE 90, 140, 80W-140, Synthetic Acceptable
Approximately 9.5 Quarts
1,550 Lbs.
– 2B –
2.0 LUBRICATION
2.4 DIFFERENTIAL CARRIERS
Recommended Lubricants
Differential carriers should have the lubricant changed at
the same interval as the rear axle on the vehicle, or approximately 10,000 miles. Drain while lubricant is warm
and clean the magnetic drain plug. Removal of the fill
plug will allow quicker drainage. Be sure to allow the
housing to drain completely. Reinstall the drain plug and
fill the housing to the bottom of the fill plug with the appropriate gear oil. Check for leaks. SAE 140 gear oil (meeting MIL-L-2105 B) is appropriate for most operating
conditions. For extreme conditions, follow the vehicle
manufacturers recommendations for the rear axle and
apply them to the front axle.
1. Gear Oil:
Temperature
Grade
Above 32° F (0° C)
MIL-L-2105
SAE 140
MIL-L-2105
80W-140
Below 32° F (0° C)
MIL-L-2105
SAE 90
MIL-L-2105
80W-90
2.5 STEERING TIE ROD ENDS
2. Chassis Grease:
Temperature
Grade
Above 32° F (0° C)
MIL-G-10294
Below 32° F (0° C)
MIL-G-10294
Tie rod ends should be lubricated every 1,000 miles at
each chassis lubrication. See Figure 1. Inspect for
loose, bent, or otherwise damaged components. Careful
attention to such detail is a vital safety factor.
2.6 SPINDLE INNER BEARINGS
3. Wheel Bearing Grease:
Temperature
Grade
Above 32° F (0° C)
NLGI Grade #2
Below 32° F (0° C)
NLGI Grade #2
The spindle inner bearings require inspection, cleaning,
and packing with grease every 16,000 miles or 1 year.
Remove the brake drum, drive flange, hub, brakes, and
spindle. Grease the spindle inner bearing surface and
pack the cavity between the bearing and seal with
grease. Special greasing tool, Fabco part number
866-0749 may be used.
See figure 1 for lubrication points. Not shown is the air
chamber mounting bracket grease fitting, located on the
bottom of the bracket tube inside the spindle yoke.
2.1 WHEEL BEARINGS
Wheel bearings require cleaning, inspection, and packing with grease at each brake reline. Wheel bearings
should be lubricated in accordance with the vehicle
manufacturer's recommendations. When greasing, liberally pack both inner and outer bearings, ensuring that
the grease has penetrated thoroughly into the cage and
roller assembly. Prior to reassembly, coat the raceways
and interior hub surfaces as well.
2.2 UNIVERSAL JOINTS
Universal joints are lubricated and sealed at the factory,
and should require no additional maintenance throughout their service life.
2.3 KINGPIN BEARINGS
Kingpin bearings should be lubricated at each chassis lubrication (approximately 1,000 mile intervals). See
Figure 1. To ensure thorough lubrication, the front axle
should be raised to relieve weight. The lower kingpin
lube fitting is located in the bottom of the lower kingpin
ball stud itself. The upper kingpin fitting is on the steering
arm or upper kingpin cap.
Figure 1
–3–
5. Torque the bearing adjusting nut to 50 lbs. ft.
while simultaneously rotating the hub assembly. Loosen the nut and repeat this procedure
2-3 times to ensure that the bearings are seated
properly. After the final tightening, back off the
nut 1/4 turn. See Figure 3.
3.0 AXLE ADJUSTMENT
3.1 GENERAL
Adjustments may be necessary after an accident, in response to or to correct steering problems, tire wear problems, or as part of the reassembly process after a
thorough inspection.
3.2 WHEEL BEARING ADJUSTMENT
1. The front of the vehicle should be raised, properly supported, and the front wheels removed
from the axle.
2. Remove the eight 1/2" outer drive flange
locknuts, and the 1 1/4" flanged axle locknut.
See Figure 2.
Figure 3
6. Install the wheel bearing lock washer, and back
off the adjusting nut just enough to allow its
dowel pin to engage in the lock washer's closest
hole. Install and torque the locknut to 400 lbs. ft.
7. Optimally, the wheel bearing end play should be
checked with a dial indicator as part of the adjustment procedure. The correct setting is
.002"-.004".
8. Reinstall the drive flange over the hub assembly. Torque the drive flange locknuts to 100 lbs.
ft., and the flanged axle locknut to 400 lbs. ft.
Figure 2
3. The drive flange should be loose enough to remove by hand. If it is not, use two 3/8"-16 bolts
in the extractor holes provided for this purpose.
Do not disturb the colored drive flange shims.
3.3 KINGPIN ADJUSTMENT
1. The front of the vehicle should be raised, properly supported, and the front wheels removed
from the axle.
4. Remove the wheel bearing locknut and washer
from the spindle and loosen the bearing adjusting nut.
2. Loosen the lower kingpin jam nut and back it
down enough to allow the lower kingpin lock
washer to disengage from its retaining dowel
pin. Back the lower kingpin ball stud down four
complete turns.
– 4–
3. Loosen the upper kingpin adjustment jam nut
and back out the adjusting screw four full turns.
The drive end assembly will begin to lower as
the screw is turned out. See Figure 4.
6. Advance the lower kingpin ball stud until the
stack of feeler gage blades begins to loosen, indicating that the ball stud threads are actually
beginning to spread the suspension and spindle
yokes apart. Back off the ball stud just enough
to allow the closest hole in the kingpin lock
washer to engage the retaining dowel pin.
Torque the locknut to 600 lbs. ft.
7. Back out the upper kingpin adjusting screw just
enough to relieve pressure so the end can turn
freely (approximately 1/16 turn) and torque the
jam nut to 45 lbs. ft.
3.4 TOE-IN ADJUSTMENT
It is not recommended to raise the front of the truck to
check toe-in; at the factory, the setting is made with the
axle loaded to simulate actual operating conditions. An
expandable toe-in alignment bar is recommended.
Since the SDA-1200, 1400, and 1600 axles use an offset
tie rod tube, adjustment is not made by turning the tube itself, but rather by rotating a small adjuster located at the
left end of the tube. See Figure 6. It is critical to making
the adjustment accurately that the front wheels are as
close to straight ahead as possible.
Figure 4
4. Begin tightening the adjusting screw and continue until upward motion of the drive end stops.
If a finger is placed near the gap between the
suspension and spindle yokes, the point at
which upward travel stops can be readily felt.
Additional resistance will also be felt in the effort
required to turn the adjusting screw. The upper
kingpin has now been seated in its bushing.
5. Place a stack of feeler gages in the gap between
the suspension and spindle yokes in the area of
the lower kingpin ball stud. The gages should fit
snugly. See Figure 5.
Figure 6
1. Loosen the tie rod adjuster clamp and left tie rod
clamp. Toe-in is increased by unscrewing the
adjuster from the tie rod itself. The correct setting is 1/16" ± 1/16" toe-in. In the case of a vehicle with full-time four-wheel drive (proportioning
differential), the setting reverts to 1/16" ± 1/16"
toe-out (greater distance in the front than the
rear). Consult a tire specialist for a specific recommendation if specialized tires are used.
2. Tighten both clamp bolts to 75 lbs. ft. Roll the
vehicle forward a distance equal to four rotations of the wheels, taking care to maintain their
straight-ahead alignment. Recheck the toe-in
and repeat this procedure if necessary to obtain
the correct dimension.
Figure 5
– 5–
1. Using a 7/16 socket, rotate the hex extension on
the front of the slack adjuster clockwise until the
shoes first contact the drum. See Figure 7. Rotate the hex extension 1/2 turn counterclockwise to back off the shoes and provide initial
running clearance. A ratcheting noise while
backing off is normal.
3.5 STEERING STOP ADJUSTMENT
The steering stop adjustment is made at the factory.
There should be no need to alter it, barring a case where
a major component such as the axle housing or a spindle
yoke has been replaced for some reason.
The turn angle is set at 35°, and this can be checked with
a carpenter's power saw protractor on the wheel's inside
rim and a T-square laid along the frame rail with the vehicle's steering at full lock. If an adjustment is necessary,
loosen the steering stop jam nut on the rear of the spindle
yoke and turn the 12-point adjusting screw. Torque the
jam nut to 75 lbs. ft. The toe-in adjustment (Section 3.4)
should be completed before performing this procedure.
NOTE: POWER STEERING STOPS IN THE VEHICLE
STEERING GEAR SHOULD NOT ALLOW THE
APPLICATION OF POWER TO THE STEERING WHEN THE STEERABLE DRIVE END IS
IN THE FULL TURN CONDITION.
3.6 CAMBER ADJUSTMENT
Camber is set at the factory and is integral to the manufacture of the housing and steerable end components. It
cannot be changed.
3.7 CASTER ADJUSTMENT
Caster is specified by the vehicle manufacturer and can
be adjusted only by means of shims between the axle
spring seat and the spring. Changing the caster will
change the pinion angle and may affect the operation of
the front drive shaft.
Figure 7
2. See that the drum rotates freely. Scraping
noises are OK, but no heavy drag should exist.
If excessive friction is present, continue to back
off the hex extension in 1/8 turn increments until
free motion is restored. Remember: It is preferable to have a slightly loose initial setting than
one that is too tight, because the adjuster will remove extra slack, but cannot add any.
3.8 BRAKE ADJUSTMENT
After an initial set-up procedure, brake adjustment is
made automatically by the slack adjusters, and should
require no attention between relines. To adjust the slack
after a brake reline:
3.9 UNIVERSAL JOINT ADJUSTMENT
Universal joint adjustment is made at the factory and is
controlled by means of shims placed between the drive
flange and the outer surface of the hub. Adjustment
should only be required if three or more of the following
components have been replaced since the unit was
manufactured: Drive flange, outer axle shaft, spindle,
spindle yoke, or hub.
To check the adjustment:
1. Turn the steerable end in question to full lock. It
may be necessary to remove the wheel to gain
sufficient access.
–6–
2. Place one end of a 6" machinist's rule against
the flat inner surface of the spindle which pilots
into the spindle yoke. See Figure 8.
3. Prepare a clean place to work. It is important
that no dirt or foreign material be allowed to enter the unit during repairs.
4. Refer to the exploded views located in the parts
section as an aid in disassembly.
5. When disassembling the various assemblies,
lay all parts on a clean bench in the same sequence as removed. This procedure will simplify reassembly and reduce the possibility of
losing parts.
6. Carefully wash and relubricate all bearings as
removed, and protectively wrap until ready for
use. Remove bearings with pullers designed
for this purpose, or in a manner which will not
damage those bearings that will be reused.
7. When necessary to apply force to remove a
part, use of a puller or press is preferred. In
some cases, use of a bar or soft hammer may
be allowable.
4.2 BRAKE DRUM, HUB, AND WHEEL
BEARINGS
1. Raise the front of the vehicle with a jack and secure with jackstands of suitable capacity. Remove front wheels.
Figure 8
3. Measure the distance to the bottom of the rectangular locating slot for the universal joint in the
yoke shaft. The measurement should be 2.141
± .030. If necessary, bring the dimension within
specification by altering the number of shims
between the drive flange and hub.
2. Remove the brake drums, taking suitable precautions if the possibility of exposure to asbestos dust exists. See Asbestos Warning located
after axle specifications. Fabco original equipment brake shoes are not asbestos based.
3. Remove the eight 1/2" outer drive flange
locknuts, and the 1 1/4" flanged axle locknut.
4.0 STEERABLE DRIVE END
DISASSEMBLY
4. The drive flange should be loose enough to remove by hand. If it is not, use two 3/8"--16 bolts
in the extractor holes provided for this purpose.
Set the colored drive flange shims aside for later
reuse.
4.1 GENERAL PRECAUTIONS FOR DISASSEMBLY
IMPORTANT: READ THIS SECTION BEFORE
STARTING THE DISASSEMBLY
PROCEDURES.
5. Remove the wheel bearing locknut, washer,
and adjusting nut from the spindle. Rock the
hub in place to loosen the outer wheel bearing
cone. Remove the cone and wrap it protectively.
1. Follow each procedure closely in each section,
making use of both text and figures.
2. The outside of the unit should be carefully
cleaned before starting disassembly. If steam
cleaning, ensure that breather and air fittings
are covered to prevent moisture from entering
assembly.
–7–
6. Remove the hub, initially attempting to pull the
assembly straight off to avoid cocking the inner
bearing cone. See Figure 9. If the cone binds
against the spindle try rocking the hub to free it,
but it may be necessary to use a pry bar under
the inner surface of the hub. To avoid damaging
the inner seal, pry against the hub only. If the inner bearing remains on the spindle when the
hub is removed, use a suitable puller to remove
it, pulling only against the bearing's race. Alternately, tap lightly on the race's outboard surface
with a small drift to correct its misalignment and
again attempt to remove it by hand.
Figure 10
3. After detaching the retaining springs, the shoes
may be removed from the brake spider plate.
Alternately, the spider plate, dust shield and
brake shoes may be removed as a unit.
4. Pry the S-camshaft's retaining snap ring out of
its groove. Set it and the shims under it aside for
reuse.
5. Pull the S-camshaft out of the air chamber
mounting bracket and slack adjuster, taking
care not to lose the washer located between
these two.
Figure 9
7. Wheel bearing cups may be driven from the hub
using a suitable puller in the slots provided in the
hub's inner cavity. Pull the cup out evenly by using both slots.
6. Remove both cotter pins and clevis pins from
the slack adjuster to detach it from the air chamber push rod. It may be necessary to turn the
adjuster slightly to withdraw the clevis pins from
their holes. See Figure 11.
NOTE: This is the limit of routine disassembly.
Brake shoes and wheel bearings may be
accessed for maintenance, but further
disassembly may be required to replace
damaged or broken parts.
4.3 BRAKE AND WHEEL SPINDLE
1. Removal of the brake shoes will be facilitated by
turning out the 7/16" adjustment screw on the
slack adjuster to relieve tension on the S-cam
rollers. Turn the screw counterclockwise until
the rollers rest at the lowest point on the cam.
2. Insert a suitable pry bar down between the top
of the brake shoe and a spindle locknut. Pry the
shoe away from the S-cam and remove the
roller. DO NOT ALLOW YOUR FINGERS TO
COME DIRECTLY BETWEEN THE SHOE
AND THE S-CAM! Relax the spring tension,
then remove the opposite roller in like fashion.
See Figure 10.
Figure 11
–8–
7. Remove the two 5/8" air chamber mounting nuts
and washers to detach the chamber from the
mounting bracket. The mounting bracket itself
can be withdrawn from the spindle yoke following removal of its two 1/2" mounting nuts.
3. Loosen the upper kingpin adjusting screw jam
nut and back out the adjusting screw until the
spindle yoke stops moving downward and is
resting on the suspension yoke. Remove the
four 3/4" steering arm or upper kingpin cap
locknuts, and pull the arm or cap up and off its
mounting studs. If difficulty is encountered, turn
the adjusting screw back in to force the arm or
cap off the studs. See Figure 13.
8. Remove the ten 5/8" locknuts which secure the
spindle and the dust shield/brake spider assembly. A little persuasion with a soft mallet may be
necessary to free up these components. See
Figure 12.
Figure 13
Figure 12
4. Remove the 7/8" upper kingpin bolt and its
locknut and two attendant washers from the
suspension yoke. Special tool number
866-0706 (see section 9.7) should now be used
to pull the upper kingpin ball stud from the suspension yoke. Do not try to remove the ball stud
by rocking the spindle yoke, as this may affect
the critical press fit between the ball stud and
suspension yoke. Fit the tool's two tubes over
two diagonally located steering arm or upper
kingpin cap studs. Insert the 1"-14 bolt through
the washer and the tool's central hole and start it
in the threads in the top of the upper kingpin ball
stud. Tighten the bolt until the ball stud is pulled
free of the suspension yoke. Remove the tool,
grasp the spindle yoke at the top, and rotate it
outward and down to disengage it from the suspension yoke.
9. The axle shaft may now be withdrawn from the
differential through the spindle yoke to provide
access to the inner axle seal. Removal of the
seal will be considerably easier if the spindle
yoke is first removed as described in the following section. Extract the seal with a suitable puller or slide hammer. Do not attempt to remove
the seal unless it is to be replaced with a new
part.
4.4 SPINDLE YOKE REMOVAL
1. Due to its high torque, loosening of the lower
kingpin locknut is more easily accomplished
while the spindle yoke is still mounted. (See
Section 9.6 for Fabco special tool number 866
600 003.) If removal of the lower kingpin ball
stud is not anticipated, removal of the spindle
yoke can be carried out with the ball stud and
locknut intact.
2. Remove the cotter pins from both tie rod ends.
Unscrew both castle nuts so that only a few
threads remain in engagement. Use a suitable
puller to extract the tie rod end from the suspension yoke. Do not strike the tie rod end ball stud.
Completely remove the nuts and tie rod.
–9–
5. Remove the lower kingpin bearing and seal
from the suspension yoke by inserting a 7/8" or
smaller flat--headed bar through the upper kingpin bolt hole so it contacts the lower kingpin
plate. See Figure 14. Strike the top of the bar to
drive out the bearing. Do not remove the upper
kingpin bearing from the spindle yoke unless it
has been determined that replacement will be
necessary. The upper bearing may be driven
out by the bottom of its inside edge using a
chisel or drift or by melting it with a propane
torch. This latter approach must be used with
caution, however.
5.2 DRYING AND CORROSION
INHIBITION
Soft clean shop towels should be used to dry parts after
cleaning. Compressed air may be used to clean accessible areas of large parts such as the housing. Bearings
should not be spun dry with compressed air as the lack of
lubrication may cause damage to the mating surfaces.
Dry parts should be immediately coated with a light oil or
a corrosion inhibitor to prevent corrosion damage. Parts
which are to be stored should also be wrapped in heavy
waxed paper.
5.3 INSPECTION
Prior to reassembly, parts which are to be reused must
be carefully inspected for signs of wear or damage. Replacement of such parts can prevent costly downtime at a
future date.
All bearing and bushing surfaces including roller bearing
cups and cones should be examined for pitting, wear, or
overheating. Shafts may be nicked and marred or have
damaged threads. Inspect all structural members and
welds closely for any signs of cracking. Parts which show
any sign of damage should be repaired or replaced.
6.0 STEERABLE DRIVE END
ASSEMBLY
6.1 GENERAL PRECAUTIONS FOR ASSEMBLY
1. Assembly
Figure 14
Refer to the exploded views located in the parts
section as an aid to assembly.
5.0 CLEANING AND INSPECTION
2. Initial Lubrication
5.1 CHOICE OF CLEANING METHODS
Splines should be coated and sealing lips on
grease seals filled with grease prior to reassembly to provide lubrication upon start up.
1. Steam may be used for external cleaning of
completely assembled units. Care must be
taken to ensure that water is kept out of the assembly by tightly closing breather caps and
other openings.
3. Bearings
Use of flanged-end bearing drivers is recommended for the installation of bearings and
races. These drivers only apply force to the
races of the bearing, preventing damage and
maintaining alignment with the shaft and bore.
2. Rough parts such as housings, which are too
large to conveniently clean with solvents, may
be immersed in a hot solution tank containing a
mild alkaline solution. Parts cleaned in hot solution tanks must be rinsed thoroughly to prevent
damage by traces of alkaline material.
4. Seals
Use a flanged type guide or driver to install
seals. If a driver is not available, use of a soft
hammer and/or wood blocks may be made, provided that care is exercised. Proprietary drivers
are available directly from Fabco and drawings
are also provided in Section 10.0
3. Parts with ground or polished surfaces, such as
bearings or shafts, should be cleaned with
emulsion cleaners or petroleum solvents. Alkaline hot solution tanks may damage the machined surfaces and should be avoided.
– 10 –
6.2 SPINDLE INSTALLATION
1. If the inner axle seal has been removed, smear
grease on the inner bushing surface of the replacement part and apply a thin bead of Loctite
#515 or equivalent to the outer surface. Drive it
into the suspension yoke until it seats squarely
against the shoulder of the bore. See Figure 15.
Figure 17
Screw the lower kingpin ball stud into the spin3. dle yoke until the top of the threaded portion is
flush with the inside surface of the yoke. Ensure
that the locating pin for the kingpin lock washer
is in position in the yoke, then loosely install the
lock washer and nut.
Figure 15
4. Smear the spherical portion of the lower kingpin
ball stud with grease. Grasping the spindle
yoke with both hands, place the lower ball stud
in its bearing and rotate the top of the spindle
yoke over the upper suspension yoke.
2. Place the lower kingpin plate in the suspension
yoke and drive in the bearing and seal after it.
Both upper and lower kingpin seals must be installed in their bores w/grease lips facing outward. If the upper kingpin bearing has been
removed, install the new part using either a
pusher plate or the old part as a driver. See Figure 16. If necessary, install a new upper kingpin
seal against its shoulder opposite the upper
kingpin bearing. See Figure 17.
5. Smear grease in the upper kingpin bearing and
start the upper ball stud through the bearing and
into its bore in the suspension yoke. Place one
upper kingpin washer on the upper kingpin bolt
and insert the bolt up through the suspension
yoke and upper kingpin ball stud. Install the
other washer and the 7/8" locknut on the bolt
and torque to 500 lbs. ft.
6. After wiping both mounting surfaces clean of
grease, push the steering arm or upper kingpin
cap down over its mounting studs, install the
four 3/4" nuts, and torque to 250 lbs. ft. Install
the upper kingpin adjusting screw, its jam nut,
and the lubrication fitting in the cap or arm.
7. Complete steps 4 – 7 of Section 3.3 (Kingpin
Adjustment) in this manual.
Figure 16
– 11 –
8. Insert the tip of the axle shaft carefully through
the inner axle seal and continue to push the assembly in until it can be felt to contact the differential. Rotate the assembly so the yoke shaft
mounting faces are horizontal. By using a bar
placed between the universal joint and the yoke
shaft as a lever, the tip of the axle shaft inside
the housing can be raised sufficiently to allow it
to engage with the differential splines. See Figure 18.
10. Install the dust shield/brake spider assembly
onto the spindle yoke studs with the large hole
positioned to receive the air chamber mounting
bracket. Install the ten 5/8" locknuts and torque
to 175 lb.-ft. On axles equipped with ABS, use
the short nuts (2 per end) on the studs used to
attach the ABS sensor bracket. See Section 10
for details.
11. Reinstall the tie rod end, torque the castle nut to
100 lb.-ft., and fit a new cotter pin.
6.3 BRAKE EQUIPMENT
1. If necessary, press new seals and bushings into
the air chamber mounting bracket. Seals must
be installed flush so that the lip side (with spring)
of both seals face toward the slack adjuster end
of the bracket. Improperly oriented seals may
allow grease to exit the camshaft head end of
the air chamber bracket and contaminate the
linings. Recess cam head end bushing 9/32".
Recess slack adjuster end bushing 22/32". See
Figure 20. Coat the bushings with grease and
install the mounting bracket on the spindle
yoke. Torque the two 1/2" bracket mounting
nuts to 150 lb.-ft.
Figure 18
9. If the spindle sleeve bearing has been removed,
press the replacement bearing into the spindle.
The groove in the bearing should be located
± 90° from the large keyway on the outside surface of the spindle. DO NOT PRESS THE TOP
OF THE BEARING IN PAST THE SPINDLE
CHAMFER! Install the yoke shaft seal in the
spindle. See Figure 19. Grease the bearing's
inner surface, and pack the cavity between
bearing and seal with grease. Slide the spindle
over the yoke shaft and spindle yoke studs. The
large keyway must be located at the 12 o'clock
position.
Figure 20
2. Push the S-camshaft all the way into the mounting bracket from the wheel side until the cam
head contacts the bracket. Left and right hand
shafts are not interchangeable. Place the inner slack adjuster washer over the splined end
of the shaft.
3. If a new air chamber is being installed, thread
the air chamber adjustment jam nut on its
pushrod. Screw the adjustment nut on after it so
that its small end is flush with the pushrod end.
Torque the jam nut to 75 lb.-ft. against the adjustment nut to lock in place. Fit the air chamber
mounting studs through their holes in the
bracket and secure with the two 5/8" locknuts
and washers. Torque to 150 lb.-ft.
Figure 19
– 12 –
4. Install the slack adjuster over the S-camshaft
with the 7/16" adjusting screw pointing toward
the front of the axle. Begin by placing two .060"
and two .030" spacers over the end of the
S-cam shaft. Install the snap ring.
6.4 WHEEL BEARINGS, HUB, AND
BRAKE DRUM
1. Press both wheel bearing cups into the hub.
Thoroughly pack both bearing cones with
grease, and coat the inside surfaces of the hub
and bearing cups. Install the inner wheel bearing cone and the hub seal in the hub. See Figure 22. Lightly coat the outer surface of the
spindle with grease to reduce the chance of the
inner wheel bearing cocking upon installation of
the hub.
5. Tap on the cam end of the shaft with a soft mallet to move the shaft inboard. Attempt to insert a
.030" spacer between the existing spacers and
the snap ring. See Figure 21. If the spacer
slides easily between the two, remove the snap
ring and install the spacer. Reinstall the snap
ring and repeat this step until a .030" spacer can
no longer be inserted.
Figure 21
Figure 22
2. Grasping the outer circumference of the hub at
the 12 and 6 o'clock positions, push the hub
straight on to the spindle. If difficulty is encountered, try rocking the hub slightly to free the inner bearing. Once the hub is in position, the
outer bearing and adjusting nut can be installed.
Perform steps 5-7 of Section 3.2 of this manual
to adjust the bearings.
6. Hook the two lower retaining springs into each
brake shoe. By grasping the shoes at the top
and spreading them apart, the circular recess in
the bottom of each shoe can be fit over the anchoring pin on the brake spider. Install the large
upper brake release spring over its two pins on
the shoes, hooks facing down. Using a bar, pry
the shoes away from the cam and insert the
camshaft rollers. DO NOT ALLOW YOUR FINGERS TO COME BETWEEN THE SHOE AND
THE S-CAM! See Figure 10.
3. Install the drive flange shims and drive flange
over the drive studs. Install the drive flange
locknuts and the flanged axle locknut and
torque to 100 and 400 lb.-ft. respectively.
7. Turn the 7/16" hex extension on the slack adjuster clockwise until it nears the air chamber
pushrod. If a new air chamber is being installed,
push the clevis pin until it snaps over the air
chamber adjusting nut. If the same slack and air
chamber are used, merely reinsert the pins and
new cotter pins back in their original holes.
4. Mount the brake drum over the wheel studs.
5. Grease all lubrication points before returning
the vehicle to service.
NOTE:
See Section 10.0, ABS PARTS &
SERVICE, for ABS information.
– 13 –
4. Attach the steerable end removal tool to a jack
and mount it to the steerable end by means of
the lowest three wheel studs and nuts. Thread
the 3/4"-16 x 3.5" bolt up through the bottom of
the base plate and into the nut furthest from the
vertical plate. Adjust the bolt to contact and
support the brake drum. If the tool is not available, alternate means to support the steerable
end must be found before continuing this procedure.
7.0 ADDITIONAL SERVICE
PROCEDURES
7.1 STEERABLE DRIVE END REMOVAL
This procedure is useful in cases where it is necessary to
gain access to the inner axle seal or to remove the differential, yet complete tear down of the steerable end is not
desirable. Removal of the steerable end will be greatly
facilitated if acquisition or fabrication of the special
mounting tool is possible. The tool may be available from
Fabco, or it can be fabricated from the drawings reproduced in Section 9.8.
5. Loosen the lower kingpin locknut and completely remove the locknut, lock washer and
lower kingpin ball stud from the spindle yoke.
6. Remove the 7/8" upper kingpin bolt and its
locknut and two attendant washers from the
suspension yoke. Special tool number 866 706
(see Section 9.7) should now be used to pull the
upper kingpin ball stud from the suspension
yoke. Fit the tool's two tubes over two diagonally located steering arm or upper kingpin cap
studs. Insert the 1"-14 bolt through the washer
and the tool's central hole and start it in the
threads in the top of the upper kingpin ball stud.
Tighten the bolt until the ball stud is pulled free
of the suspension yoke.
1. Remove the cotter pins from both tie rod ends.
Unscrew both castle nuts so that only a few
threads remain in engagement. Use a suitable
puller to extract the tie rod end from the suspension yoke. Do not strike the tie rod end ball stud.
Completely remove the nuts and tie rod.
2. Remove all eight 12-point cap screws which secure the universal joint to the axle shaft and
yoke shaft. Pry the joint away from the shafts
and remove. See Figure 23.
7. Roll the jack backward to disengage the steerable end from the axle. See Figure 24.
Figure 23
3. Loosen the upper kingpin adjusting screw jam
nut and back out the adjusting screw until the
spindle yoke stops moving downward and is
resting on the suspension yoke. Remove the
four 3/4" steering arm or upper kingpin cap
locknuts, and pull the arm or cap up off its
mounting studs. If difficulty is encountered, turn
the adjusting screw back in to force the arm or
cap off the studs. See Figure 13.
Figure 24
8. Installation is the reverse of removal. See Section 8.0 for correct torque specifications. After
assembly, complete the kingpin adjustment
procedure (Section 3.3), and grease upper and
lower kingpins.
– 14 –
7.2 DIFFERENTIAL CARRIER REMOVAL
NOTES:
1. Remove the oil drain and fill plugs from the differential housing to drain lubricant.
2. Remove the tie rod and both steerable ends as
described in Section 7.1. Withdraw both axle
shafts from the axle.
3. Remove the four screws and nuts and the vertical extension of the steerable end/differential
carrier removal tool. Remove the two lowest
bolts from the differential pinion bearing carrier,
maneuver the tool into place, and reinstall the
bolts through the tool and back into the differential. Thread the 3/4"-16 x 3.5" bolt up through
the bottom of the base plate and into the nut
closest to the vertical plate. Adjust the bolt to
contact and support the differential carrier. If
the tool is not available, alternate means to support the differential carrier must be found before
continuing this procedure.
4. Remove all differential mounting bolts, washers
and nuts. Roll the differential carrier away from
the axle. Refer to the appropriate differential
service manual for information regarding differential servicing.
5. Installation is the reverse of removal. Apply a
bead of Loctite #515 or equivalent around the
differential carrier mounting face on the axle
housing. See Figure 25. Coat the mounting bolt
threads as well to avoid seepage. Use a bar as
depicted in figure 18 to ease axle shaft installation. See Section 8.0 for correct torque values.
Figure 25
6. Clean the magnetic drain plug, and fill the axle
to the bottom edge of the level hole with the appropriate lubricant.
– 15 –
PG. 22
0.000
.19
1.50
1.06
2.25
VP 2/99
0.000
1.69
.56
Item #1
MATERIAL LIST
ITEM
PG. 26
1
3
MATERIAL
QTY.
1
3” O.D. x 7/8 Wall Mild Steel Tubing
1
2
358-0223 - 45° Grease Fitting
1
3
675-0330-B46 - O-Ring
1
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