1994 JEEP CHEROKEE wheel bolts

(9) Disconnect the tie rod from the steering
knuckle. Disconnect the steering dampener from the
axle bracket.
(10) Support the axle with a hydraulic jack under
the differential. Raise the axle just enough to relieve
the axle weight from the springs.
(11) Remove the spring U-bolts from the plate
brackets.
(12) Loosen BUT DO NOT REMOVE the bolts that
attach the spring rear pivot at the frame rail brack-
ets. This will allow the springs to pivot without bind-
ing on the bushings.
(13) Disconnect shackle from the springs and lower
the springs to the surface.
(14) Lower the jack enough to remove the axle.
INSTALLATION
CAUTION: All suspension components that use rub-
ber bushings should be tightened with the vehicle
at the normal height. It is important to have the
springs supporting the weight of the vehicle when
the fasteners are torqued. If the springs are not at
their normal ride position, vehicle ride comfort
could be affected along with premature rubber
bushing wear. Rubber bushings must never be lu-
bricated.
(1) Support the axle on a hydraulic jack under the
differential. Position the axle under the vehicle.
(2) Raise the springs and install the spring shackle
bolts.Do not tighten at this time.
(3) Lower the axle and align the spring center
bolts with the locating holes in the axle pads and
plate brackets.
(4) Install the spring U-bolts through the plate
brackets and tighten to 122 Nzm (90 ft. lbs.) torque.
(5) Connect the track bar to the axle bracket and
install the bolt.Do not tighten at this time.
It is important that the springs support the
weight of the vehicle when the track bar is con-
nected. If the springs are not at their usual po-
sition, the vehicle ride comfort could be affected.
(6) Install the shock absorber and tighten the nut
to 61 Nzm (45 ft. lbs.) torque.
(7) Install the stabilizer bar link to the axle
bracket. Tighten the nut to 61 Nzm (45 ft. lbs.)
torque.
(8) Install the tie rod to the steering knuckles and
tighten the nuts to 47 Nzm (35 ft. lbs.) torque. Install
the steering dampener to the axle bracket and
tighten the bolt to 75 Nzm (55 ft. lbs.) torque.
(9) Install the brake components and ABS brake
sensor (if equipped). Refer to Group 5ÐBrakes.
(10) Connect the vent hose to the tube fitting and
axle shift motor vacuum harness.(11) Align the reference marks and connect the
drive shaft to the axle yoke. Tighten the U-joint
clamp bolts to 19 Nzm (14 ft. lbs.) torque.
(12) Check differential lubricant and add if neces-
sary.
(13) Install the wheel and tire assemblies.
(14) Remove the supports and lower the vehicle.
(15) Tighten the spring rear pivot bolt/nut to 142
Nzm (105 ft. lbs.) torque. Tighten the spring shackle
bolt/nut to 135 Nzm (100 ft. lbs.) torque.
(16) Tighten the track bar nut at the axle bracket
to 100 Nzm (74 ft. lbs.) torque.
(17) Check the front wheel alignment.
LUBRICANT CHANGE
The gear lubricant will drain quicker if the vehicle
has been recently driven.
(1) Raise and support the vehicle.
(2) Remove the lubricant fill hole plug from the
differential housing cover.
(3) Remove the differential housing cover and
drain the lubricant from the housing.
(4) Clean the housing cavity with a flushing oil,
light engine oil or lint free cloth.Do not use water,
steam, kerosene or gasoline for cleaning.
(5) Remove the sealant from the housing and cover
surfaces. Use solvent to clean the mating surfaces.
(6) Apply a bead of MOPARtSilicone Rubber Seal-
ant to the housing cover (Fig. 1).Allow the sealant
to cure for a few minutes.
Install the housing cover within 5 minutes af-
ter applying the sealant. If not installed the seal-
ant must be removed and another bead applied.
Fig. 1 Typical Housing Cover With Sealant
2 - 22 FRONT SUSPENSION AND AXLEJ

(7) Install the cover and any identification tag.
Tighten the cover bolts in a criss-cross pattern to 41
Nzm (30 ft. lbs.) torque.
(8) Refill the differential with MOPARtHypoid
Gear Lubricant within 13 mm (1/2 in.) below the fill
plug hole.
(9) Install the fill hole plug and lower the vehicle.
PINION SEAL REPLACEMENT
CAUTION: The following procedures must be used
so the correct pinion bearing preload torque is re-
tained. If this procedure is not followed, the result
can be premature failure of the rear axle.
REMOVAL
(1) Raise and support the vehicle.
(2) Remove wheel and tire assemblies.
(3) Mark the propeller shaft yoke and pinion yoke
for installation alignment reference.
(4) Remove the propeller shaft from the yoke.
(5) Rotate the pinion gear three or four times.
Make sure brakes are not dragging during this
procedure.
(6) Measure the amount of torque (in Newton-
meters or inch-pounds) necessary to rotate the pinion
gear with a torque wrench. Note the torque for in-
stallation reference.It must be known to properly
adjust the pinion gear bearing preload torque
after seal installation.
(7) Remove the pinion yoke nut and washer. Use
Remover C-452 and Wrench C-3281 to remove the
pinion yoke (Fig. 2).
(8) Mark the positions of the yoke and pinion gear
for installation alignment reference.(9) Use Remover W-251 to remove the pinion gear
seal (Fig. 3).
INSTALLATION
(1) Apply a light coating of gear lubricant on the
lip of pinion seal. Install seal with Installer W-147-E
and Handle C-4171 (Fig. 4).
(2) Align the reference marks and install yoke on
the pinion gear with Installer W-162-D.
(3) Install a new pinion nut on pinion shaft.
Tighten the nut only enough to remove the shaft
end play.
Fig. 2 Pinion Yoke Removal
Fig. 3 Seal Removal
Fig. 4 Pinion Seal Installation
JFRONT SUSPENSION AND AXLE 2 - 23

CAUTION: Never loosen the pinion gear nut to de-
crease the pinion gear bearing preload torque. If the
specified preload torque is exceeded, a new col-
lapsible spacer must be installed. The torque se-
quence will have to be repeated.
(4) Install a socket and inch-pound torque wrench
on the pinion nut.
(5) Rotate the shaft with the torque wrench and
note the torque.
Required preload torque is the amount re-
corded during removal plus an additional 0.56
Nzm (5 in. lbs.).
(6) Use Flange Wrench C-3281 to retain the yoke
and shaft (Fig. 5). Tighten the shaft nut in very
small increments.
(7) Continue tightening the shaft nut in small in-
crements until the correct bearing preload torque is
attained.
(8) Align the installation reference marks and at-
tach the propeller shaft to the yoke.
(9) Add API grade GL 5 hypoid gear lubricant to
the differential housing, if necessary.
(10) Install wheel and tire assemblies.
(11) Remove support and lower the vehicle.
HUB BEARING AND AXLE SHAFT
REMOVAL
(1) Raise and support the vehicle.
(2) Remove the wheel and tire assembly.
(3) Remove the brake components from the axle,
refer to Group 5, Brakes.
(4) Remove the cotter pin, nut retainer and axle
hub nut (Fig. 6).(5) Remove the hub to knuckle bolts (Fig. 6). Re-
move the hub from the steering knuckle and axle
shaft.
(6) Remove the disc brake rotor shield from the
bearing carrier (Fig. 6).
(7) On disconnect axles, remove vacuum shift mo-
tor housing. Refer to Vacuum Disconnect Axle in this
section.
(8) Remove the axle shaft from the housing.Avoid
damaging the axle shaft oil seals in the differen-
tial.
Fig. 5 Tightening Pinion Shaft Nut
Fig. 6 Hub, Knuckle and Axle Shaft
2 - 24 FRONT SUSPENSION AND AXLEJ

INSTALLATION
(1) Thoroughly clean the axle shaft (Fig. 6) and ap-
ply a thin film of Mopar Wheel Bearing Grease to
the shaft splines, seal contact surface, hub bore.
(2) Install the axle shaft into the housing and dif-
ferential side gears. Avoid damaging the axle shaft
oil seals in the differential.
(3) Install the hub bearing and brake dust shield
to the knuckle.
(4) Install the hub to knuckle bolts and tighten to
102 Nzm (75 ft. lbs.) torque.
(5) Install the hub washer and nut. Tighten the
hub nut to 237 Nzm (175 ft. lbs.) torque. Install the
nut retainer and a new cotter pin (Fig. 6).
(6) Install the brake components, refer to Group 5,
Brakes.
(7) Install the wheel and tire assembly.
(8) Remove support and lower the vehicle.
AXLE SHAFTÐ CARDAN U-JOINT
DISASSEMBLY
Single cardan U-joints are not serviceable. If defec-
tive, they must be replaced as a unit. If the bearings,
seals, spider or bearing caps are damaged or worn,
replace the complete U-joint.
CAUTION: Clamp only the forged portion of the
yoke in the vise. Also, to avoid distorting the yoke,
do not over tighten the vise jaws.
(1) Remove the bearing cap retaining snap rings
(Fig. 7).
It can be helpful to saturate the bearing caps
with penetrating oil prior to removal.(2) Locate a socket that is larger in diameter than
the bearing cap. Place the socket (receiver) against
the yoke and around the perimeter of the bearing cap
to be removed. Locate a socket that is smaller in di-
ameter than the bearing cap. Place the socket (driv-
er) against the opposite bearing cap. Position the
yoke with the sockets in a vise (Fig. 8).
(3) Compress the vise jaws to force the bearing cap
into the larger socket (receiver).
(4) Release the vise jaws. Remove the sockets and
bearing cap that was partially forced out of the yoke.
(5) Repeat the above procedure for the remaining
bearing cap.
(6) Remove the remaining bearing cap, bearings,
seals and spider from the propeller shaft yoke.
CLEANING AND INSPECTION
(1) Clean all the U-joint yoke bores with cleaning
solvent and a wire brush. Ensure that all the rust
and foreign matter are removed from the bores.
(2) Inspect the yokes for distortion, cracks and
worn bearing cap bores.
(3) Replace the complete U-joint if any of the com-
ponents are defective.
ASSEMBLY
(1) Pack the bearing caps 1/3 full of wheel bearing
lubricant. Apply extreme pressure (EP), lithium-base
lubricant to aid in installation.
(2) Position the spider in the yoke. Insert the seals
and bearings. Tap the bearing caps into the yoke
bores far enough to hold the spider in position.
Fig. 7 Axle Shaft Outer U-Joint
Fig. 8 Yoke Bearing Cap Removal
JFRONT SUSPENSION AND AXLE 2 - 25

Use Mopar Multi Mileage grease to lubricate drum
brake pivot pins and rear brakeshoe contact points
on the support plates. Use GE 661, or Dow 111 sili-
cone grease on caliper bushings and mounting bolts.
Use fresh brake fluid or Mopar brake cleaner to
clean or flush brake system components. These are
the only cleaning materials recommended.
CAUTION: Never use gasoline, kerosene, methyl or
isopropyl alcohol, paint thinner, or any fluid con-
taining mineral oil to clean the system components.
These fluids damage rubber cups and seals. If sys-
tem contamination is suspected, check the fluid for
dirt, discoloration, or separation into distinct layers.
Drain and flush the system with new brake fluid if
contamination is suspected.
JEEP BODY CODE LETTERS
The body/model identification code letters for Jeep
vehicles are as follows:
²Code letters XJ: Cherokee
²Code letters YJ: Wrangler/YJ
The code letters are used throughout this group to
simplify model identification and component applica-
tion.
BRAKE SAFETY PRECAUTIONS
WARNING: ALTHOUGH FACTORY INSTALLED
BRAKELINING ON JEEP VEHICLES IS MADE FROM
ASBESTOS FREE MATERIALS, SOME AFTER MARKET
BRAKELINING MAY CONTAIN ASBESTOS. THIS
SHOULD BE TAKEN INTO ACCOUNT WHEN REPAIR-
ING A VEHICLE WITH PRIOR BRAKE SERVICE. WEAR
A RESPIRATOR WHEN CLEANING BRAKE COMPO-
NENTS AS ASBESTOS FIBERS CAN BE A HEALTH
HAZARD. NEVER CLEAN WHEEL BRAKE COMPO-
NENTS WITH COMPRESSED AIR. USE A VACUUM
CLEANER SPECIFICALLY DESIGNED FOR REMOVING
BRAKE DUST. IF A VACUUM CLEANER IS NOT AVAIL-
ABLE, CLEAN THE PARTS WITH WATER DAMPENED
SHOP RAGS. DO NOT CREATE DUST BY SANDING
BRAKELINING. DISPOSE OF ALL DUST AND DIRT
SUSPECTED OF CONTAINING ASBESTOS FIBERS IN
SEALED BAGS OR CONTAINERS. FOLLOW ALL REC-
OMMENDED SAFETY PRACTICES PRESCRIBED BY
THE OCCUPATIONAL SAFETY AND HEALTH ADMINIS-
TRATION (OSHA) AND THE ENVIRONMENTAL PRO-
TECTION AGENCY (EPA), FOR HANDLING AND
DISPOSAL OF PRODUCTS CONTAINING ASBESTOS.
5 - 2 BRAKESJ

Brake drag also has a direct effect on fuel economy.
If undetected, minor brake drag can be misdiagnosed
as an engine or transmission/torque converter prob-
lem.
Minor drag will usually cause slight surface char-
ring of the lining. It can also generate hard spots in
rotors and drums from the overheat/cool down pro-
cess. In most cases, the rotors, drums, wheels and
tires are quite warm to the touch after the vehicle is
stopped.
Severe drag can char the brake lining all the way
through. It can also distort and score rotors and
drums to the point of replacement. The wheels, tires
and brake components will be extremely hot. In se-
vere cases, the lining may generate smoke as it chars
from overheating.
An additional cause of drag involves the use of in-
correct length caliper mounting bolts. Bolts that are
too long can cause a partial apply condition. The cor-
rect caliper bolts have a shank length of 67 mm
(2.637 in.), plus or minus 0.6 mm (0.0236 in.). Refer
to the Disc Brake service section for more detail on
caliper bolt dimensions and identification.
Some common causes of brake drag are:
²loose or damaged wheel bearing
²seized or sticking caliper or wheel cylinder piston
²caliper binding on bushings or slide surfaces
²wrong length caliper mounting bolts (too long)
²loose caliper mounting bracket
²distorted brake drum or shoes
²rear brakeshoes binding on worn/damaged support
plates
²severely rusted/corroded components
²misassembled components.
If brake drag occurs at all wheels, the problem may
be related to a blocked master cylinder compensator
port or faulty power booster (binds-does not release).
The brakelight switch can also be a cause of drag.
An improperly mounted or adjusted brakelight
switch can prevent full brake pedal return. The re-
sult will be the same as if the master cylinder com-
pensator ports are blocked. The brakes would be
partially applied causing drag.
BRAKE FADE
Brake fade is a product of overheating caused by
brake drag. However, overheating and subsequent
fade can also be caused by riding the brake pedal,
making repeated high deceleration stops in a short
time span, or constant braking on steep roads. Refer
to the Brake Drag information in this section for
causes.
PEDAL PULSATION
Pedal pulsation is caused by components that are
loose, or beyond tolerance limits.
Disc brake rotors with excessive lateral runout or
thickness variation, or out of round brake drums arethe primary causes of pulsation. Other causes are
loose wheel bearings or calipers and worn, damaged
tires.
PULL
A front pull condition could be the result of:
²contaminated lining in one caliper
²seized caliper piston
²binding caliper
²wrong caliper mounting bolts (too long)
²loose caliper
²loose or corroded mounting bolts
²improper brakeshoes
²damaged rotor
²incorrect wheel bearing adjustment (at one wheel)
A worn, damaged wheel bearing or suspension
component are further causes of pull. A damaged
front tire (bruised, ply separation) can also cause
pull. Wrong caliper bolts (too long) will cause a par-
tial apply condition and pull if only one caliper is in-
volved.
A common and frequently misdiagnosed pull condi-
tion is where direction of pull changes after a few
stops. The cause is a combination of brake drag fol-
lowed by fade at the dragging brake unit.
As the dragging brake overheats, efficiency is so
reduced that fade occurs. If the opposite brake unit is
still functioning normally, its braking effect is mag-
nified. This causes pull to switch direction in favor of
the brake unit that is functioning normally.
When diagnosing a change in pull condition, re-
member that pull will return to the original direction
if the dragging brake unit is allowed to cool down
(and is not seriously damaged).
REAR BRAKE GRAB
Rear grab (or pull) is usually caused by contami-
nated lining, bent or binding shoes and support
plates, or improperly assembled components. This is
particularly true when only one rear wheel is in-
volved. However, when both rear wheels are affected,
the master cylinder or proportioning valve could be
at fault.
BRAKES DO NOT HOLD AFTER DRIVING
THROUGH DEEP WATER PUDDLES
This condition is generally caused by water soaked
lining. If the lining is only wet, it can be dried by
driving with the brakes lightly applied for a mile or
two. However, if the lining is both wet and dirty, dis-
assembly and cleaning will be necessary.
BRAKE FLUID CONTAMINATION
There are two basic causes of brake fluid contami-
nation. The first involves allowing dirt, debris, or
other liquid materials to enter the cylinder reservoirs
JBRAKES 5 - 9

DISC BRAKES
INDEX
page page
Caliper Assembly........................ 29
Caliper Cleaning and Inspection............. 28
Caliper Disassembly...................... 27
Caliper Installation........................ 30
Caliper Operation and Wear Compensation..... 24
Caliper Removal......................... 27
Disc Brake Rotor Refinishing................ 32
Disc Brake Rotor Runout................... 31Disc Brake Rotor Thickness................ 31
Disc Brake Rotor Thickness Variation......... 31
Disc Brakeshoe Installation................. 26
Disc Brakeshoe Removal.................. 25
General Information....................... 24
Rotor Installation......................... 30
Rotor Removal.......................... 30
Wheel Nut Tightening..................... 32
GENERAL INFORMATION
1994 Jeep XJ/YJ models are equipped with single
piston, floating-type disc brake calipers. Ventilated,
cast rotors are used for all applications.
The disc brake calipers are supported in mounting
arms that are an integral part of the steering
knuckle. The calipers slide on mounting bolts that
also attach the calipers to the steering knuckle.
CALIPER OPERATION AND WEAR COMPENSATION
Caliper Operation
The significant feature of single piston caliper op-
eration is that the calipers are free to slide laterally
on the mounting bolts. It is the freedom of lateral
movement that allows continous compensation for
lining wear.
A simplified cross section of a single piston caliper
is shown in Figure 1. The illustration graphically
portrays the forces at work when the brakes are ap-
plied.
Upon brake application, fluid pressure exerted
against the caliper piston increases greatly. Of equal
importance, is the fact that this fluid pressure is ex-
erted equally and in all directions. What this means,
is that pressure in the caliper bore, will be exactly
the same as pressure on the piston. In other words,
pressure against piston and caliper bore will be
equal.
Fluid pressure applied to the piston is transmitted
directly to the inboard brakeshoe. This forces the
shoe lining against the inner surface of the disc
brake rotor (Fig. 1).
At the same time, fluid pressure within the piston
bore, forces the caliper to slide inward on the mount-
ing bolts. This action brings the outboard brakeshoe
lining into contact with the outer surface of the disc
brake rotor (Fig. 1).
In summary, fluid pressure acting simultaneously
on both piston and caliper, produces a strong clamp-
ing action. When sufficient force is applied, friction
will stop the rotors from turning and bring the vehi-
cle to a stop.Brakeshoe Wear Compensation
Application and release of the brake pedal gener-
ates only a very slight movement of the caliper and
piston. Upon release of the pedal, the caliper and pis-
ton return to a rest position. The brakeshoes do not
retract an appreciable distance from the rotor. In
fact, clearance is usually at, or close to zero. The rea-
sons for this are to keep road debris from getting be-
tween the rotor and lining and in wiping the rotor
surface clear each revolution.
The caliper piston seal controls the amount of pis-
ton extension needed to compensate for normal lining
wear.
During brake application, the seal is deflected out-
ward by fluid pressure and piston movement (Fig. 2).
When the brakes (and fluid pressure) are released,
the seal relaxes and retracts the piston.
The amount of piston retraction is determined by
brakelining wear. Generally, the amount is just
Fig. 1 Disc Brake Caliper Operation
5 - 24 BRAKESJ

enough to maintain contact between the piston and
inboard brakeshoe. Brakelining running clearance at
the rotor, will be held between zero and a maximum
of 0.12 mm (0.005 in.).
DISC BRAKESHOE REMOVAL
(1) Raise vehicle and remove front wheels.
(2) Drain small amount of fluid from master cylin-
der front brake reservoir with suction gun.
(3) Bottom caliper piston in bore with C-clamp. Po-
sition clamp screw on outboard brakeshoe and clamp
frame on rear of caliper. Typical C-clamp attachment
is shown in Figure 3.Do not allow clamp screw to
bear directly on outboard shoe retainer spring.
Use wood or metal spacer between shoe and
clamp screw if necessary.
(4) Remove caliper mounting bolts (Fig. 4).If
brakeshoes are being removed to correct a pull
or drag condition, verify length of caliper bolts
as they may be incorrect length. Refer to bolt in-
formation in brakeshoe installation procedure.
(5) Tilt top of caliper outward. Use pry tool if nec-
essary (Fig. 5).
(6) Lift caliper off steering knuckle (Fig. 6).
(7)If original brakeshoes will be used, keep
them in sets (left and right); they are not inter-
changeable.(8) Remove outboard shoe. Press one end of shoe
inward to disengage shoe lug. Then rotate shoe up-
ward until retainer spring clears caliper. Press oppo-
site end of shoe inward to disengage shoe lug and
rotate shoe up and out of caliper (Fig. 7).
Fig. 2 Lining Wear Compensation By Piston Seal
Fig. 3 Bottoming Caliper Piston With C-Clamp
Fig. 4 Removing/Installing Caliper Mounting Bolts
Fig. 5 Tilting Caliper Outward
Fig. 6 Caliper Removal
JBRAKES 5 - 25