Fabco SDA-2300 User manual

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SDA-2300 STEERABLE DRIVE AXLE
SERVICE MANUAL
FabcoAutomotiveCorporation, Livermore, CA Ph: [phone] 1- (800) 967- 8838 FAX [phone] www.fabcoautomotive.com
9/03
AUTOMOTIVE CORPORATION

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 dis-
ease 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 Ad-
ministration (OSHA) has established very stringent limitations for exposure to as-
bestos 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. Dispos-
able dust face masks are not allowed by OSHA.
2. Do not smoke while working on any asbestos related material or wearing protec-
tive 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 effi-
ciency vacuum cleaners suitable for use with asbestos. Do not dry brush depos-
its 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 cloth-
ing 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 dan-
gers involved and to provide suitable training, precaution and protection for
those working in an asbestos environment.

TABLE OF CONTENTS – SDA-2300
PAGE
1.0 INTRODUCTION ....................................................................................................................... 5
1.1 General Description............................................................................................................ 5
1.2 Operation............................................................................................................................ 5
1.3 Operating Instructions ........................................................................................................ 5
1.4 Specifications ..................................................................................................................... 6
1.5 Steerable Drive Axle General Dimensions ......................................................................... 7
2.0 LUBRICATION........................................................................................................................... 8
2.1 Wheel Bearings .................................................................................................................. 8
2.2 Universal Joints .................................................................................................................. 8
2.3 Kingpin Bearings ................................................................................................................ 8
2.4 Differential Carrier .............................................................................................................. 8
2.5 Steering Tie Rod Ends ....................................................................................................... 8
3.0 AXLE ADJUSTMENT .............................................................................................................. 8
3.1 General............................................................................................................................... 8
3.2 Wheel Bearing Adjustment................................................................................................. 8-9
3.3 Kingpin Adjustment ............................................................................................................ 9-10
3.4 Toe-In Adjustment .............................................................................................................. 10
3.5 Steering Stop Adjustment................................................................................................... 11
3.6 Camber Adjustment............................................................................................................ 11
3.7 Caster Adjustment.............................................................................................................. 11
3.8 Brake Adjustment ............................................................................................................... 11
4.0 STEERABLE DRIVE END DISASSEMBLY ..................................................................... 11
4.1 General Precautions for Disassembly ................................................................................ 11-12
4.2 Brake Drum, Hub, and Wheel Bearings ............................................................................. 12
4.3 Brake and Wheel Spindle................................................................................................... 12-13
4.4 Spindle Yoke Removal ....................................................................................................... 14-15
5.0 CLEANING AND INSPECTION............................................................................................ 15
5.1 Choice of Cleaning Methods .............................................................................................. 15
5.2 Drying and Corrosion Inhibition .......................................................................................... 15
5.3 Inspection ........................................................................................................................... 15
6.0 STEERABLE DRIVE END ASSEMBLY ............................................................................ 16
6.1 General Precautions for Assembly..................................................................................... 16
6.2 Spindle Installation ............................................................................................................. 16-17
6.3 Brake Equipment................................................................................................................ 17-18
6.4 Wheel Bearings, Hub, and Brake Drum ............................................................................. 18-19

TABLE OF CONTENTS CONT'D. – SDA-2300
PAGE
7.0 ADDITIONAL SERVICE PROCEDURES.......................................................................... 19
7.1 Steerable Drive End Removal ............................................................................................ 19-20
7.2 Differential Carrier Removal ............................................................................................... 20
8.0 TORQUE SPECIFICATIONS ................................................................................................ 21
9.0 SPECIAL TOOLS...................................................................................................................... 22
9.1 Wheel End Inner Seal Driver.............................................................................................. 22
9.2 Wheel Hub Seal Driver....................................................................................................... 23
9.3 Lower Kingpin Seal Driver.................................................................................................. 24
9.4 Lower Kingpin Bearing Driver............................................................................................. 25
9.5 Upper Kingpin Seal Driver.................................................................................................. 26
9.6 Upper Kingpin Bearing Driver............................................................................................. 27
9.7 Inner Axle Seal Driver ........................................................................................................ 28
9.8 Upper Kingpin Ball Stud Puller ........................................................................................... 29
9.9 Camshaft Seal Driver ( Brake Bracket ) ............................................................................. 30
9.10 Camshaft Bushing Driver ( Brake Bracket ) ....................................................................... 31
9.11 Camshaft Seal Driver ( Spindle Yoke )............................................................................... 32
9.12 Camshaft Bushing Driver ( Spindle Yoke )......................................................................... 33
9.13 Differential & Steerable End Removal Tool Assembly ....................................................... 34
9.13A Differential & Steerable End Removal Tool ....................................................................... 35
9.13B Differential Removal Adapter ............................................................................................. 36
9.13C Steerable End Removal Adapter 13 3/16" B.C................................................................... 37
9.14 Lower Kingpin Locknut Tool ............................................................................................... 38
9.15 Lower Kingpin Ball Stud Removal Tool .............................................................................. 39
9.16 Hub Bearing Locknut Tool.................................................................................................. 40
10.0 ILLUSTRATED PARTS MANUAL....................................................................................... 42
Copyright © 1996 Fabco Automotive Corporation, 151 Lawrence Drive, Oakland, CA 94551

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 steering arm is usually located on the
left steerable end, although right hand or even dual
steering arms are available.
1.2 OPERATION
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.
When steered, the outer section of each steerable drive
end rotates about the kingpin centerline. The U-joint, cen-
tered on the kingpin centerline, allows power to be trans-
mitted throughout the possible range of steering inputs.
The axle is equipped with S-cam air brakes and automatic
slack adjusters.
1.3 OPERATING INSTRUCTIONS
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 spin-
ning. Engagement is best accomplished when the engine
is pulling lightly.
–5–
AXLE HOUSING
DIFFERENTIAL CARRIER STEERABLE DRIVE
END

1.4 STEERABLE DRIVE AXLE SPECIFICATIONS — FABCO MODEL SDA-2300
MAXIMUM CAPACITY 23,000 Pounds Load Rating
BRAKES
Type Drum, `S' Cam
Size 16.5 Diameter x 7 Inch
Chamber 30 Square Inch
Certification FMVSS 121
Slack Adjusters Automatic
HOUSING Fabricated Steel, Cast Banjo, Center Bowl
CAMBER 1/2° Positive
WHEELS
Mounting 10-Studs on 13.19 Inch Bolt Circle
Minimum Wheel Size 20 Inch
DIFFERENTIAL CARRIER Spiral Bevel
Ring Gear Diameter 18 Inch
Pinion Spline 2.100 Diameter, 41 Spline Involute
Single Reduction Ratios 3.55, 3.70, 3.90, 4.11, 4.33, 4.56
4.88, 5.29, 5.43, 6.17, 6.50, 6.67
UNIVERSAL JOINT Single Cardan, 10C
KINGPINS
Type Spherical, Nylatron Races
Inclination 5°
STEERING Ackerman to Match Wheelbases
160" to 185" or 186" to 219"
Single or Dual Steering Arms
TRACK 91.75 Inches Across Wheel Mounting Faces
AXLE SHAFTS
Spline 2.312 Inch Diameter, 36 Spline Involute
Body 2.16 Inch Diameter
TURN ANGLE 35°
LUBRICATION
Type SAE 90, 140, 80W--140
Capacity Approximately 17 Quarts
WEIGHT – Dry 2,100 Lbs.
OPTIONS
CTI Central Tire Inflation (CTI)
ABS Anti-lock Braking System Sensors (ABS)
Wheel Ends ISO/Hub Piloted Wheel Ends
Double Reduction Differential 5.04, 5.31, 5.60, 5.90, 6.20,
6.64, 7.39, 8.40, 9.08
–6–
1/96

–7–
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STEERABLE DRIVE AXLE GENERAL DIMENSIONS
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2.0 LUBRICATION
Recommended Lubricants
1. Gear Oil:
Temperature Grade
Above 32° F (0° C) MIL-L-2105 B
SAE 140
MIL-L-2105 C
80W-140
Below 32° F (0° C) MIL-L-2105 B
SAE 90
MIL-L-2105 C
80W-90
2. Chassis Grease:
Temperature Grade
Above 32° F (0° C) MIL-G-10294
Below 32° F (0° C) MIL-G-10294
3. Wheel Bearing Grease:
Temperature Grade
Above 32° F (0° C) NLGI Grade #2
Below 32° F (0° C) NLGI Grade #2
There are four lubrication points on each steerable end.
The location of these grease fittings is as follows; inside
the lower kingpin ball stud, tie rod end, S-camshaft tube,
and the upper kingpin cap or steering arm.
2.1 WHEEL BEARINGS
Wheel bearings require cleaning, inspection, and pack-
ing with grease at each brake reline. Wheel bearings
should be lubricated in accordance with the vehicle
manufacturer's recommendations. When greasing, lib-
erally 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 through-
out their service life.
2.3 KINGPIN BEARINGS
Kingpin bearings should be lubricated at each chassis lu-
brication (approximately 1,000 mile intervals). To ensure
thorough lubrication, the front axle should be raised
slightly to relieve vehicle weight. The lower kingpin lube
fitting is located at the bottom of the lower kingpin ball
stud itself. The upper kingpin fitting is on the steering arm
or upper kingpin cap.
2.4 DIFFERENTIAL CARRIERS
Differential carriers should have the lubricant changed at
the same interval as the rear axle on the vehicle, or ap-
proximately 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 appro-
priate gear oil. Check for leaks. SAE 140 gear oil (meet-
ing 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.
2.5 STEERING TIE ROD ENDS
Tie rod ends should be lubricated every 1,000 miles at
each chassis lubrication. Inspect for loose, bent, or oth-
erwise damaged components. Careful attention to such
detail is a vital safety factor.
3.0 AXLE ADJUSTMENT
3.1 GENERAL
Adjustments may be necessary after an accident, in re-
sponse to or to correct steering problems, tire wear prob-
lems, 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, prop-
erly supported, and the front wheels removed
from the axle.
2. Then remove the brake drum.
3. Remove the eight 5/8" outer drive flange
locknuts.
4. The drive flange should be loose enough to re-
move by hand. If it is not, use two 1/2"-20 bolts
in the extractor holes provided for this purpose.
See Figure 1.
–8–
1/96
Figure #1

5. Remove the wheel bearing locknut and washer
from the spindle and loosen the bearing adjust-
ing nut.
6. Torque the bearing adjusting nut to 50 lb.-ft.
while simultaneously rotating the hub assem-
bly. (See Section Special Tools 9.16.) 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 2.
7. Install the wheel bearing lock washer and wheel
bearing adjustment nut, then torque locknut to
400 lb.-ft. (See Section Special Tools 9.16.)
Next, one tab on the lockwasher should be bent
inward and one bent outward across the flattest
part of the nut.
NOTE: With the outer locknut torqued to
specifications the wheel hub should
rotate freely
8. The wheel bearing end play should be checked
with a dial indicator as part of the adjustment
procedure. See Figure 3. The correct end play
setting is no less than .002" and no more than
.004".
9. Reinstall the drive flange over the hub assem-
bly. Then torque the drive flange locknuts to
175 lb.- ft.
3.3 KINGPIN ADJUSTMENT
1. The front of the vehicle should be raised, prop-
erly supported, and the front wheels removed
from the axle.
2. Loosen the lower kingpin locknut (see Section
9.14 Special Tools) and back it down enough to
allow the lower kingpin lock washer to disen-
gage from its retaining dowel pin. Remove the
grease fitting. Back the lower kingpin ball stud
(see Section 9.15 Special Tools) down four
complete turns.
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.
4. Begin tightening the adjusting screw and con-
tinue until upward motion of the steerable 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 or drift in the gap
between the suspension and spindle yokes in
the area of the lower kingpin ball stud. The
gages or drift should fit snugly. Filling the gap.
No measurement is necessary. See Figure 5A.
–9–
7/99
Figure #2
Figure #3
Figure #4

6. Advance the lower kingpin ball stud until the
feeler gage stack or drift loosens. (See Section
Special Tools 9.15.) This indicates that the ball
stud threads are actually beginning to spread
the suspension and spindle yokes apart. See
Figure #5A
7. Back off the ball stud enough to allow the clos-
est hole in the lower kingpin lock washer to en-
gage the retaining dowel pin. Apply grease to
the surface of the lower kingpin lock washer that
will face the locknut. This helps keep the
washer from turning when the locknut is tight-
ened. Torque the locknut to 2,000 lb.-ft. (See
Section Special Tools 9.14)
CAUTION: DO NOT TORQUE LOWER
KINGPIN BALL STUD.
8. 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 75 lb.-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 but if
unavailable consult an alignment specialist. Since the
SDA-1800, 2100, and 2300 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 or
right end of the tie rod tube. See Figure 6. It is critical to
making the adjustment accurately that the front wheels
are as close to straight ahead as possible. Loosen the tie
rod adjuster and tie rod clamp.
1. Whichever end the tie rod adjuster is located
toe-in is increased by unscrewing the adjuster
from the tie rod itself. The correct setting is
0- 1/8" toe-in. In the case of a vehicle with full-
time four-wheel drive (proportioning differen-
tial), the setting reverts to 0-1/8" toe-out
(greater distance in the front than the rear).
Consult a tire specialist for a specific recom-
mendation if specialized tires are used.
2. Tighten both clamp bolts to 75 lb.-ft. Roll the ve-
hicle 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.
–10–
7/99
Figure #6
Figure #5
Figure #5A
YOKE
LOWER KINGPIN BA LL STUD

3.5 STEERING STOP ADJUSTMENT
The steering stop adjustment is made at the factory.
There should be no need to alter it, unless a major com-
ponent such as the axle housing or 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 vehi-
cle's steering at full lock. If an adjustment is necessary,
loosen the steering stop 12-point adjusting screw on the
rear of the spindle yoke and add or remove washers to
achieve desired turn angle. Torque the jam nut to
75 lb.-ft. The toe-in adjustment (Section 3.4) should be
completed before performing this procedure.
WARNING: THE POWER STEERING GEAR'S PRES-
SURE RELIEF SHOULD OCCUR AT
LEAST 1/8" BEFORE THE AXLE STEER-
ING STOPS ARE CONTACTED. IF THE
POWER STEERING PRESSURE RELIEF
NEEDS ADJUSTMENT CONSULT THE
VEHICLE MANUFACTURER BEFORE
OPERATING THE VEHICLE. FAILURE
TO COMPLY CAN RESULT IN DAMAGE
TO THE STEERABLE DRIVE AXLE AND
OTHER STEERING COMPONENTS.
3.6 CAMBER ADJUSTMENT
Camber is set at the factory and is integral to the manu-
facture 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.
3.8 BRAKE ADJUSTMENT
After an initial setup 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:
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. Ro-
tate the hex extension 1/2 turn counterclock-
wise to back off the shoes and provide initial
running clearance. A ratcheting noise while
backing off is normal.
2. Confirm 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.
NOTE: It is preferable to have a slightly loose
initial setting than one that is too tight.
The adjuster will remove extra slack,
but cannot add any.
4.0 STEERABLE DRIVE END
DISASSEMBLY
4.1 GENERAL PRECAUTIONS FOR
DISASSEMBLY
CAUTION:READ THIS SECTION BEFORE START-
ING THE DISASSEMBLY PROCEDURES.
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
the assembly.
3. Prepare a clean place to work. It is important
that no dirt or foreign material be allowed to en-
ter 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 se-
quence as removed. This procedure will sim-
plify reassembly and reduce the possibility of
losing parts.
–11–
1/96
Figure #7

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 dam-
age those bearings that will be reused.
7. When necessary to apply force to remove a
part, the use of a puller or press is preferred. In
some cases, the 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 se-
cure with jackstands of suitable capacity. Also
remove the front wheels.
2. Remove the brake drums.
WARNING: WHEN REMOVING THE BRAKE
DRUMS TAKE SUITABLE PRE-
CAUTIONS IF THE POSSIBILITY
OF EXPOSURE TO ASBESTOS
DUST EXISTS. SEE ASBESTOS
WARNING LOCATED IN THE
FRONT OF THIS MANUAL.
FABCO ORIGINAL EQUIPMENT
BRAKE SHOES ARE NOT AS-
BESTOS BASED.
3. Remove the eight 5/8" outer drive flange
locknuts.
4. The drive flange should be loose enough to re-
move by hand. If it is not, use two 1/2"-20 bolts
in the extractor holes provided for this purpose.
See Figure 8.
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 protec-
tively.
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 damag-
ing 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 re-
move it, pulling only against the bearing's race.
Alternately, tap lightly on the race's outboard
surface with a small drift to correct its misalign-
ment and again attempt to remove it by hand.
7. Wheel bearing cups may be removed from the
hub using a suitable puller. Pull the cup out
evenly.
NOTE: This is the limit of routine disassembly.
Brake shoes and wheel bearings may
be accessed for maintenance, but fur-
ther 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. See Figure 10. Turn the screw counter-
clockwise until the rollers rest at the lowest point
on the cam.
–12–
1/96
Figure #8
Figure #9

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. Relax the spring tension, then remove
the opposite roller in like fashion. See Figure 11
WARNING: DO NOT ALLOW YOUR FIN-
GERS TO COME DIRECTLY BE-
TWEEN THE SHOE AND THE
S-CAM !
3. Next, remove the push rod from the slack ad-
juster clevis by loosening the locknut. See
Figure 12.
4. To remove the S-camshaft pry the retaining
snap ring, located on the slack adjuster end of
the S-camshaft, out of its groove then pull the
S-camshaft out of the air chamber mounting
bracket. At the same time remove the shims,
slack adjuster, and the washer located between
the slack adjuster and air chamber bracket.
5. To remove the brake shoes detach the top re-
taining spring from the lower shoe. Then with
shoe in hand lower down to detach the release
springs at the anchor pins. Now the other brake
shoe is free to be removed.
6. Remove the two 5/8" air chamber mounting
nuts and washers to detach the chamber from
the mounting bracket. The mounting bracket it-
self can be withdrawn from the spindle yoke fol-
lowing removal of its two 7/8" mounting bolts.
7. Remove the ten 3/4" self locking nuts which se-
cure the spindle. A little persuasion with a soft
mallet may be necessary to free up these com-
ponents. See Figure 13.
–13–
1/96
Figure #12
Figure #11
Figure #10
Figure #13

4.4 SPINDLE YOKE REMOVAL
1. Due to its high torque, loosening the 4 1/8" lower
kingpin locknut (see Section 9.14 Special
Tools) will require substantial leverage. Re-
move the grease fitting from the lower kingpin
ball stud. Now the ball stud can be removed.
(See Section 9.15 Special Tools.)
See Figure 14.
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 suspen-
sion yoke. Completely remove the nuts and tie
rod.
WARNING: DO NOT STRIKE THE TIE ROD
END BALL STUD.
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
two 7/8" steering arm or upper kingpin cap
locknuts and bolts. Then pull the steering arm
or cap up and off the mounting studs and locat-
ing dowel. If difficulty is encountered, turn the
adjusting screw back in to force the arm or cap
off the studs. See Figure 15.
4. Remove the drive yoke bearing retaining snap
ring and thrust washer. The yoke shaft bearing
removal is optional. Remember to repack the
bearing upon installation.
5. Remove the 1"-14 upper kingpin bolt. Special
tool number 866 744 (see section 9.8 Special
Tools) should now be used to pull the upper
kingpin ball stud from the suspension yoke.
See Figure 15A. Fit one tube over the locating
dowel and the other is allowed to float freely. In-
sert the 1 1/8"-12 bolt through the spacer and
the tool's central hole. The bolt should then be
threaded into 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 firmly and disengage it
from the suspension yoke. An over-head crane
would make this procedure a lot easier.
CAUTION: DO NOT TRY TO REMOVE THE
UPPER KINGPIN BALL STUD BY
ROCKING THE SPINDLE YOKE,
AS THIS MAY AFFECT THE
CRITICAL PRESS FIT BETWEEN
THE BALL STUD AND SUSPEN-
SION YOKE.
CAUTION: DO NOT PROCEED FURTHER
UNLESS THE DIFFERENTIAL OIL
HAS BEEN DRAINED.
6. Remove the drive and axle shaft assemblies by
sliding them out of the axle housing being very
careful not to score the inner axle seal. See Fig-
ure 16. No need to take this assembly apart un-
less replacing the cross and bearing.
–14–
1/96
Figure #15A
Figure #14
Figure #15
UPP ER KI NGPI N
BA LL ST UD PU L LER
UPPER KINGPIN
BALL STUD
SPI N DLE Y OKE

7. Remove the lower kingpin bearing and seal
from the suspension yoke by inserting a 7/8" or
smaller flat-headed bar through the upper king-
pin bolt hole so it contacts the lower kingpin
plate. See Figure 17. 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 is nec-
essary. The upper bearing may be driven out by
the bottom of its inside edge using a chisel or
drift.
5.0 CLEANING AND INSPECTION
5.1 CHOICE OF CLEANING METHODS
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 as-
sembly by tightly closing breather caps and
other openings.
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 solu-
tion tanks must be rinsed thoroughly to prevent
damage by traces of alkaline material.
3. Parts with ground or polished surfaces, such as
bearings or shafts, should be cleaned with
emulsion cleaners or petroleum solvents. Alka-
line hot solution tanks may damage the ma-
chined surfaces and should be avoided.
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 accessi-
ble 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. Re-
placement 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.
–15–
1/96
Figure #17
Figure #16

6.0 STEERABLE DRIVE END
ASSEMBLY
6.1 GENERAL PRECAUTIONS FOR
ASSEMBLY
1. Assembly
Refer to the exploded views located in the parts
section as an aid to assembly.
2. Initial Lubrication
Splines and grease seal lips should be coated
and filled with grease prior to reassembly to pro-
vide lubrication upon start up.
3. Bearings
Use of flanged-end bearing drivers is recom-
mended 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.
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, pro-
vided that care is exercised. Proprietary drivers
are available directly from Fabco and drawings
are also provided in Section 10.0
6.2 SPINDLE INSTALLATION
1. If the inner axle seal has been removed, smear
grease on the inner bushing surface of the re-
placement part and apply a thin bead of Loctite
gasket eliminator to the outer surface. Drive it
into the suspension yoke until it seats squarely
against the shoulder of the bore.
CAUTION THE BRONZE INNER BUSHING
SURFACE HAS AN OIL PASSAGE
WHICH SHOULD BE LOCATED
AT 3 OR 9 O'CLOCK BEFORE
THE SEAL IS DRIVEN IN.
2. Place the lower kingpin plate in the suspension
yoke and drive in the bearing and seal after it.
See Figure 18. 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 ei-
ther a pusher plate or the old part as a driver.
See Figure 19. If necessary, install a new upper
kingpin seal against its shoulder opposite the
upper kingpin bearing.
3. If necessary, install a new wheel end inner seal.
See Figure 20. Grease lightly all seal lips and
kingpin bearings.
4. Reinstall the drive axle shaft assemblies being
careful not to score the inner axle seal.
–16–
1/96
Figure #19
Figure #18
Figure #20

5. Place the spindle yoke on the suspension yoke,
optimally with some lifting device. See
Figure 21. Install the upper kingpin ball stud and
bolt. It is recommended to replace the bolt with
a new one from Fabco. If a replacement bolt is
not available, use the existing bolt and apply
Loctite #272 to its threads during assembly.
Torque the bolt to 1,000 lb.-ft.
6. Reinstall the yoke shaft bearing, if removed,
making sure it is packed liberally with grease.
See Figure 22. Replace the thrust washer and
snap ring.
7. Smear the spherical portion of the lower kingpin
ball stud with grease. Screw the lower kingpin
ball stud into the spindle yoke. Ensure that the
locating pin for the kingpin lock washer is in po-
sition in the yoke, then loosely install the lock
washer and nut.
8. After wiping both mounting surfaces clean of
grease, push the steering arm or upper kingpin
cap down over its mounting studs and pilot
dowel, install the two 3/4" nuts, and torque to
250 lb.-ft. Install the upper kingpin adjusting
screw, its jam nut, and the lubrication fitting in
the cap or arm.
9. Complete steps 4-7 of Section 3.3 (Kingpin Ad-
justment) in this manual.
10. Install the spindle over the yoke shaft and spin-
dle yoke studs. See Figure 23.
CAUTION: THE KEYWAY MUST BE LO-
CATED IN THE 12 O'CLOCK PO-
SITION.
Torque the spindle nuts to 250 lb.-ft. using a uni-
formed torque sequence.
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 and spindle
yoke. Seals must be installed flush so that the
lip side (with spring) of both seals face toward
the slack adjuster end of the bracket. Improp-
erly oriented seals may allow grease to exit the
camshaft head end and contaminate the brake
linings.
CAUTION: THE CAM HEAD END BUSHING
SHOULD BE RECESSED 5/16"
TO ALLOW CLEARANCE FOR
THE SEAL. THE BRAKE
BRACKET BUSHING SHOULD BE
RECESSED 23/32" TO ALLOW
CLEARANCE FOR THE SEAL.
2. Push the S-camshaft all the way into the mount-
ing braket from the wheel side until the cam
head contacts the bracket. Next, push the
camshaft tube onto the shaft. Make sure that
the O-rings are set in the grooves on the cam-
shaft tube.
CAUTION: LEFT AND RIGHT HAND
S-CAMSHAFTS ARE NOT
INTERCHANGEABLE.
–17–
7/99
Figure #23
Figure #22
Figure #21

3. Push the air chamber mounting bracket onto the
S-camshaft. Then align the bracket on the
steering arm or upper kingpin cap. Insert the
two 7/8" bolts and torque to 250 lb.-ft.
4. 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. See
Figure 24.
5. Install the inner washer and 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-camshaft. Install the snap ring.
See Figure 25.
6. Tap on the cam end of the shaft with a soft mal-
let to move the shaft inboard. Attempt to insert a
.030" spacer between the existing spacers and
the snap ring. If the spacer slides easily be-
tween 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 in-
serted.
7. Thread the air chamber push rod into the clevis
until it bottoms out. Then back off two turns and
torque locknut to 75 lb.-ft.
8. 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 an-
choring pin on the spindle yoke. Install the large
upper brake release spring. Then using a bar,
pry the shoes away from the S-cam and insert
the camshaft rollers. See Figure 26.
CAUTION: DO NOT ALLOW YOUR FINGERS
TO COME BETWEEN THE SHOE
AND THE S-CAM!
9. Refer to Section 3.8 for brake adjustment.
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 bear-
ing cone and the hub seal in the hub. See
Figure 27. 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.
–18–
7/99
Figure #25
Figure #24
Figure #27
Figure #26

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 encoun-
tered, try rocking the hub slightly to free the in-
ner bearing. Once the hub is in position, the
outer bearing and adjusting nut can be installed.
Refer to section 3.2 for wheel bearing adjust-
ment.
3. Install drive flange over the drive studs. Install
the drive flange locknuts and torque to 175 lb-ft.
using a uniformed torque sequence.
4. Mount the brake drum over the wheel studs.
5. Grease all lubrication points before returning
the vehicle to service.
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 differ-
ential, 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 steerable end removal
tool is available from Fabco, or it can be fabricated from
the drawings in Section 9.13 Special Tools.
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 suspen-
sion 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 se-
cure the universal joint to the axle shaft and
yoke shaft. Pry the joint away from the shafts
and remove. See Figure 28.
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.
4. Remove the steering arm or upper kingpin cap
nuts along with the brake bracket bolts. Using a
7/16 socket, rotate the hex extension on the
front of the slack adjuster counter clockwise. At
the same time the brake bracket will be lifted
back off the steering arm or upper kingpin cap.
5. Remove the steering arm or upper kingpin cap.
If difficulty is encountered, turn the adjusting
screw back in to force the arm or cap off the
studs.
6. Attach the steerable end removal tool to a trans-
mission jack and mount it to the steerable end
by means of the lowest three wheel studs and
nuts. Thread the 3/4"-16 x 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.
CAUTION: IF THE TOOL IS NOT AVAILABLE,
ALTERNATE MEANS TO SUP-
PORT THE STEERABLE END
MUST BE FOUND BEFORE CON-
TINUING THIS PROCEDURE.
7. Loosen the lower kingpin locknut (see Section
9.14 Special Tools) and completely remove the
locknut, lock washer and lower kingpin ball stud
(see Section 9.15 Special Tools) from the spin-
dle yoke.
8. Remove the 1"-14 upper kingpin bolt. Special
tool number 866 744 (see Section 9.8) should
now be used to pull the upper kingpin ball stud
from the suspension yoke. Using the upper
kingpin ball stud puller, fit one tube over the lo-
cating dowel and the other is allowed to float
freely. Insert the 1 1/8"-12 x 3 1/2" UNF bolt
through the spacer and the tool's central hole.
The bolt should then be threaded into the top of
the upper kingpin ball stud. Tighten the bolt until
the ball stud is pulled free from the suspension
yoke.
9. Roll the jack backward to disengage the steer-
able end from the axle. See Figure 29 & 30.
–19–
1/96
Figure #28