1995 JEEP YJ differential

(14) Invert the differential case and start two ring
gear bolts. This will provide case-to-ring gear bolt
hole alignment.
(15) Install new ring gear bolts and alternately
tighten to 95-122 Nzm (70-90 ft. lbs.) torque (Fig. 17).
(17) Lubricate all differential components with hy-
poid gear lubricant.
Fig. 17 Ring Gear Bolt Installation
3 - 50 REAR SUSPENSION AND AXLESJ

AXLE SPECIFICATIONS
MODEL 35 AXLE
Axle Type...............................Semi-Floating Hypoid
Lubricant................SAE Thermally Stable 80W-90
Lubricant Trailer Tow.............Synthetic 75W-140
Lube Capacity..............................1.66 L (3.50 pts.)
Axle Ratio................................3.07, 3.55, 3.73, 4.10
Differential
Bearing Preload ............................0.1 mm (0.004 in.)
Side Gear Clearance ............0-0.15 mm (0-0.006 in.)
Ring Gear
Diameter .......................................19.2 cm (7.562 in.)
Backlash.........................0-0.15 mm (0.005-0.008 in.)
Pinion Std. Depth...................96.8 mm (3.813 in.)
Pinion Bearing Preload
Original Bearing ....................1-2Nzm (10-20 in. lbs.)
New Bearing .......................1.5-4Nzm (15-35 in. lbs.)
8 1/4 AXLE
Axle Type................................Semi-floating, hypoid
Lubricant...............................................SAE 75W-90
Lube Capacity................................2.08 L (4.4 pts.)
Axle Ratios.........................................3.07 3.55 4.10
Differential
Side Gear Clearance ..................0.12 mm (0.005 in.)
Case Flange Runout ..................0.07 mm (0.003 in.)
Bearing Preload ...........................95 Nzm (70 ft. lbs.)
Ring Gear
Diameter .......................................20.95 cm (8.25 in.)
Backlash....................0.12-0.20 mm (0.005-0.008 in.)
Runout .......................................0.127 mm (0.005 in.)
Pinion Bearing
Preload ....................................1-2 Nzm (10-20 in.lbs.)
TORQUE SPECIFICATIONS
XJ REAR SUSPENSION COMPONENTS
DESCRIPTION ................................................TORQUE
Shock Absorber
Upper Bolt ...................................23 Nzm (17 ft. lbs.)
Lower Nut ....................................62 Nzm (46 ft. lbs.)
Stabilizer Bar
Clamp Bolt ...................................54 Nzm (40 ft. lbs.)
Link Upper Bolt ............................12 Nzm (9 ft. lbs.)
Link Lower Nut ..........................74 Nzm (55 ft. lbs.)
Spring
U-Bolt Nut ...................................70 Nzm (52 ft. lbs.)
Front Pivot Bolt ......................148 Nzm (109 ft. lbs.)
Upper Shackle Bolt .................148 Nzm (109 ft. lbs.)
Lower Shackle Bolt ...................108 Nzm (80 ft. lbs.)
YJ REAR SUSPENSION COMPONENTS
DESCRIPTION ................................................TORQUE
Shock Absorber
Upper Nut ....................................61 Nzm (45 ft. lbs.)
Lower Nut ....................................61 Nzm (45 ft. lbs.)
Track Bar
Frame Bracket Nut.................142 Nzm (105 ft. lbs.)
Axle Bracket Nut ....................142 Nzm (105 ft. lbs.)Spring
U-Bolt Nut .................................122 Nzm (90 ft. lbs.)
Rear Shackle Bolts..................136 Nzm (100 ft. lbs.)
Front Pivot Bolt ......................142 Nzm (105 ft. lbs.)
MODEL 35 AXLE
DESCRIPTION ................................................TORQUE
Fill Hole Plug...........................34 Nzm (25 ft. lbs.)
Diff. Cover Bolt........................41 Nzm (30 ft. lbs.)
Bearing Cap Bolt.....................77 Nzm (57 ft. lbs.)
Pinion Nut...............292-427 Nzm (215-315 ft. lbs.)
Ring Gear Bolt.............95-122 Nzm (70-90 ft. lbs.)
RWAL/ABS Sensor Bolt.........24 Nzm (18. ft. lbs.)
8 1/4 AXLE
DESCRIPTION ................................................TORQUE
Diff. Cover Bolt........................47 Nzm (35 ft. lbs.)
Bearing Cap Bolt.....................95 Nzm (70 ft. lbs.)
Pinion Nut.............................285 Nzm (210 ft. lbs.)
Ring Gear Bolt.........................95 Nzm (70 ft. lbs.)
RWAL/ABS Sensor Bolt.........24 Nzm (18. ft. lbs.)
JREAR SUSPENSION AND AXLES 3 - 51

BRAKES
CONTENTS
page page
ABS BRAKE DIAGNOSIS................... 3
ABS OPERATION AND SERVICE............ 33
BRAKE FLUIDÐBRAKE BLEEDINGÐ
BRAKELINES AND HOSES............... 10
DISC BRAKES.......................... 45
DRUM BRAKES......................... 55
GENERAL INFORMATION.................. 1MASTER CYLINDERÐCOMBINATION VALVE . . 15
PARKING BRAKES....................... 60
POWER BRAKE BOOSTERÐBRAKE PEDALÐ
BRAKELIGHT SWITCH.................. 22
SERVICE BRAKE DIAGNOSIS............... 4
SPECIFICATIONS........................ 70
GENERAL INFORMATION
INDEX
page page
Antilock Brakes (ABS)....................... 1
Brake Components......................... 1
Brake Fluid/Lubricants/Cleaning Solvents......... 2
Brake Safety Precautions.................... 2Brake Warning Lights....................... 1
Brakelining Material........................ 1
Jeep Body Code Letters..................... 2
BRAKE COMPONENTS
Power assist front disc and rear drum brakes are
standard on Cherokee/Wrangler models. Disc brake
components consist of single piston calipers and ven-
tilated rotors. Rear drum brakes are dual shoe units
with cast brake drums.
The parking brake mechanism is lever and cable
operated. The cables are attached to levers on the
rear drum brake secondary shoes. The parking
brakes are operated by a foot pedal on YJ models and
a hand lever on XJ models.
A 205 mm dual diaphragm vacuum power brake
booster is used for all applications. Two master cylin-
ders are used; 4-cylinder YJ models have a one-piece
master cylinder. All other models have a two-piece
master cylinder with plastic reservoir.
All models are equipped with a combination valve.
The valve contains a pressure differential valve and
switch and a fixed rate rear proportioning valve.
BRAKELINING MATERIAL
Factory brakelining on all models consists of an or-
ganic base material combined with metallic particles.
The lining does not contain asbestos.
BRAKE WARNING LIGHTS
Cherokee/Wrangler models are equipped with one
or two brake warning lights. A red warning light is
standard on all models. An amber light is added on
models with ABS brakes. Both lights are located in
the instrument panel.
The red light is in circuit with the pressure differ-
ential switch (in the combination valve), and with the
parking brake switch. The light alerts the driver
when the parking brakes are applied, or when a
pressure differential exists between the front and
rear hydraulic systems. The light also illuminates for
a few seconds at start up as part of a bulb check.
The ABS warning light is amber in color and is lo-
cated in the same side of the instrument cluster as
the red warning light. The amber light only illumi-
nates when an ABS circuit fault occurs.
ANTILOCK BRAKES (ABS)
An antilock brake system (ABS) is available on
Cherokee/Wrangler models as an option. The system
is an electronically operated, all-wheel brake control
system. The ABS system is designed to prevent
wheel lockup during periods of high wheel slip brak-
ing. Refer to the antilock brake section for operation
and service information.
JBRAKES 5 - 1

hand lever. Also note if vehicle was being operated
with parking brake partially applied (this will cause
red light to remain on).
(7) Check brake pedal operation. Verify that pedal
does not bind and has adequate free play. If pedal
lacks free play, check pedal and power booster for be-
ing loose or for bind condition. Do not road test until
condition is corrected.
(8) If components inspected look OK, road test ve-
hicle.
ROAD TESTING
(1) If amber warning light is on, problem is with
antilock system component. Refer to antilock diagno-
sis section.
(2) If red warning light is not on, proceed to step
(4).
(3) If red warning light is on, proceed as follows:
(a) See if parking brakes are applied. If brakes
are applied, release them and proceed to step (4).
(b) Note if brake pedal is abnormally low. If
pedal is definitely low and red light is still on,
check front/rear hydraulic circuits for leak.Do not
road test. Inspect and repair as needed.
(4) Check brake pedal response with transmission
in Neutral and engine running. Pedal should remain
firm under steady foot pressure. If pedal falls away,
do not road test as problem is in master cylinder, or
HCU on ABS models. If pedal holds firm, proceed to
next step.
(5) During road test, make normal and firm brake
stops in 25-35 mph range. Note faulty brake opera-
tion such as hard pedal, pull, grab, drag, noise, fade,
etc.
(6) Return to shop and inspect brake components.
Refer to inspection and diagnosis information.
COMPONENT INSPECTION
Fluid leak points and dragging brake units can
usually be located without removing any components.
The area around a leak point will be wet with fluid.
The components at a dragging brake unit (wheel,
tire, rotor) will be quite warm or hot to the touch.
Other brake problem conditions will require compo-
nent removal for proper inspection. Raise the vehicle
and remove the necessary wheels for better visual ac-
cess.
During component inspection, pay particular atten-
tion to heavily rusted/corroded brake components
(e.g. rotors, caliper pistons, brake return/holddown
springs, support plates, etc.).
Heavy accumulations of rust may be covering se-
vere damage to a brake component. It is wise to re-
move surface rust in order to accurately determine
the depth of rust penetration and damage. Light sur-
face rust is fairly normal and not a major concern (as
long as it is removed). However, heavy rust buildup,especially on high mileage vehicles may cover struc-
tural damage to such important components as
brakelines, rotors, support plates, and brake boost-
ers. Refer to the wheel brake service procedures in
this group for more information.
BRAKE WARNING LIGHT OPERATION
The red brake warning light will illuminate under
the following conditions:
²for 2-3 seconds at startup as part of normal bulb
check
²when parking brakes are applied
²low pedal caused by leak in front/rear brake hy-
draulic circuit
If the red light remains on after startup, first ver-
ify that the parking brakes are fully released. Then
check pedal action and fluid level. A red light plus
low pedal indicates the pressure differential switch
and valve have been actuated due to a system leak.
On models with ABS brakes, the amber warning
light only illuminates when an ABS malfunction has
occurred. The ABS light operates independently of
the red warning light.
PEDAL FALLS AWAY
A brake pedal that falls away under steady foot
pressure is generally the result of a system leak. The
leak point could be at a brakeline, fitting, hose,
wheel cylinder, or caliper. Internal leakage in the
master cylinder caused by worn or damaged piston
cups, may also be the problem cause.
If leakage is severe, fluid will be evident at or
around the leaking component. However internal
leakage in the master cylinder will not be physically
evident. Refer to the cylinder test procedure at the
end of this section.
LOW PEDAL
If a low pedal is experienced, pump the pedal sev-
eral times. If the pedal comes back up, worn lining
and worn rotors or drums are the most likely causes.
However, if the pedal remains low and the red warn-
ing light is on, the likely cause is a leak in the hy-
draulic system.
A decrease in master cylinder fluid level may only
be the result of normal lining wear. Fluid level will
drop somewhat as lining wear occurs. It is a result of
the outward movement of caliper and wheel cylinder
pistons to compensate for normal wear.
SPONGY PEDAL
Air in the system is the usual cause of a spongy
pedal. Brake drums machined way beyond allowable
limits (too thin), or substandard brake lines and
hoses can also cause a condition similar to a spongy
JSERVICE BRAKE DIAGNOSIS 5 - 5

MASTER CYLINDERÐCOMBINATION VALVE
INDEX
page page
Combination Valve Replacement (Non-ABS)..... 16
General Service Information................. 15
Master Cylinder and Combination Valve Installation
(With ABS)............................. 20
Master Cylinder and Combination Valve Removal
(With ABS)............................. 17Master Cylinder Bench Bleeding.............. 21
Master Cylinder Installation (Non-ABS)......... 16
Master Cylinder Overhaul (4-Cylinder Models).... 16
Master Cylinder Removal (Non-ABS)........... 15
Reservoir Replacement (2-Piece Master Cylinder) . 19
GENERAL SERVICE INFORMATION
Master Cylinder
Two different master cylinders are used. A one-piece
cast aluminum cylinder is used on 4-cylinder YJ models
(Fig. 1). All other models have a two-piece master cylin-
der with removable nylon reservoir (Fig. 2).
The two master cylinders are serviced differently.
The reservoir and grommets are the only replaceable
parts on the two-piece master cylinder. The one-piece
master cylinder can be overhauled when necessary.
Combination Valve
A combination valve is used in all models. The
valve contains a pressure differential valve and
switch and a rear brake proportioning valve. The
valve is not repairable. It must be replaced if diagno-
sis indicates this is necessary.
The pressure differential switch is connected to the
brake warning light. The switch is actuated by move-
ment of the switch valve. The switch monitors fluid
pressure in the separate front/rear brake hydraulic cir-
cuits.
A decrease or loss of fluid pressure in either hydraulic
circuit will cause the switch valve to shuttle to the low
pressure side. Movement of the valve pushes the switch
plunger upward. This action closes the switch internal
contacts completing the electrical circuit to the red
warning light. The switch valve will remain in an actu-
ated position until repairs are made.
The rear proportioning valve is used to balance front-
rear brake action. The valve allows normal fluid flow
during moderate effort brake stops. The valve only con-
trols (meters) fluid flow during high effort brake stops.
MASTER CYLINDER REMOVAL (NON-ABS)
(1) Remove air cleaner hose, cover and housing.
Fig. 1 Master Cylinder And Combination Valve
(4-Cyl. YJ Models)
Fig. 2 Master Cylinder And Combination Valve (All
Except 4-Cyl. YJ Models)
JMASTER CYLINDERÐCOMBINATION VALVE 5 - 15

(2) Disconnect brake lines at master cylinder and
combination valve.
(3) Remove nuts attaching master cylinder to
booster studs.
(4) Remove master cylinder.
(5) Remove cylinder cover and drain fluid.
(6) If two-piece master cylinder reservoir requires
service, refer to reservoir replacement procedure in
this section.
MASTER CYLINDER INSTALLATION (NON-ABS)
(1) Bleed master cylinder on bench before installa-
tion. Refer to procedure in this section.
(2) If new two-piece master cylinder is being in-
stalled, remove plastic protective sleeve from primary
piston shank. Also check condition of seal at rear of
cylinder body. Reposition seal if dislodged. Replace
seal if cut, or torn.
(3) Clean cylinder mounting surface of brake booster.
Use shop towel wetted with brake cleaner for this pur-
pose. Dirt, grease, or similar materials will prevent
proper cylinder seating and could result in vacuum leak.
(4) Slide master cylinder onto brake booster studs.
(5) Install nuts attaching master cylinder to booster
studs. Tighten nuts to 25 Nzm (220 in. lbs.) torque.
(6) Connect brakelines to master cylinder and com-
bination valve (Figs. 1 and 2).
(7) Fill and bleed brake system.
COMBINATION VALVE REPLACEMENT (NON-ABS)
The combination valve is not a repairable compo-
nent. The valve is serviced as an assembly whenever
diagnosis indicates replacement is necessary.
(1) Remove air cleaner cover and hose for access to
valve, if necessary.
(2) Disconnect differential pressure switch wire at
combination valve. Do not pull switch wire to discon-
nect. Unsnap connecter lock tabs to remove.
(3) Disconnect brakelines at combination valve and
remove valve.
(4) Connect brakelines to replacement valve. Start
line fittings by hand to avoid cross threading.
Tighten fittings snug but not to required torque at
this time.
(5) Connect wire to pressure differential switch.
(6) Bleed brakes.
(7) Tighten brakeline fittings to 18-24 Nzm
(160-210 in. lbs.) torque after bleeding.
MASTER CYLINDER OVERHAUL (4-CYLINDER
MODELS)
CYLINDER DISASSEMBLY
(1) Examine cylinder cover seal. Discard seal if
torn or distorted.
(2) Clamp cylinder in vise (Fig. 3).(3) Remove piston retaining snap ring. Press and
hold primary piston inward with wood dowel or sim-
ilar tool. Then remove snap ring (Fig. 4).
(4) Remove and discard primary piston (Fig. 5).
Piston is serviced only as assembly.
(5) Remove secondary piston (Fig. 6). Apply air
pressure through rear outlet port to ease piston out
of bore. Cover small ports at bottom of rear reservoir
with towel to prevent air leakage.
(6) Discard secondary piston. Do not disassemble
piston as components are only serviced as assembly.
MASTER CYLINDER CLEANING AND
INSPECTION
Clean the cylinder with Mopar brake cleaning sol-
vent or clean brake fluid. Remove cleaning residue
with compressed air.
Inspect the cylinder bore. A light discoloration of
Fig. 3 Mounting Cylinder In Vise
Fig. 4 Removing/Installing Piston Snap Ring
5 - 16 MASTER CYLINDERÐCOMBINATION VALVEJ

(5) Remove air cleaner housing from engine com-
partment.
(6) Disconnect wire from combination valve pres-
sure differential switch (Fig. 9). Do not pull wire to
disconnect. Unsnap lock tabs on wire connecter.
(7) Disconnect canister vacuum line at manifold
fitting (Fig. 10).
(8) Disconnect brake booster vacuum hose at in-
take manifold fitting (Fig. 11). Move hose aside for
working clearance.(9) Unseat small S-clip that secures brakelines
(Fig. 12).
(10) Remove brakeline that connects master cylin-
der front port to combination valve front port (Fig.
12).
(11) Disconnect master cylinder rear brakeline at
cylinder. Then loosen line at combination valve and
swing line around to opposite side of cylinder (Fig.
13).
(12) Disconnect rear brakeline at HCU (Fig. 14).
(13) Disconnect both flex brakelines at HCU (Fig.
14).
(14) Disconnect HCU line to rear brakes at HCU
port (Fig. 14).
(15) Remove nut attaching combination valve
bracket to brake booster stud.
(16) Remove combination valve and brakelines as
assembly (Fig. 15). Work valve bracket off booster
stud. Then work brakelines around cylinder and
HCU and remove assembly.
Fig. 9 Pressure Differential Switch Wire Connection
Fig. 10 Canister Vacuum Line Location (At Manifold
Fitting)
Fig. 11 Booster Vacuum Hose Removal/Installation
(From Manifold Fitting)
Fig. 12 Master Cylinder Front Brakeline Removal/
Installation
Fig. 13 Disconnecting Master Cylinder Rear
Brakeline
5 - 18 MASTER CYLINDERÐCOMBINATION VALVEJ

(7) Install combination valve as follows:
(a) Work combination valve and brakelines into
position.
(b) Slide combination valve bracket onto booster
stud closest to driver side fender (Fig. 25). Then in-
stall bracket attaching nut but do not fully tighten
nut at this time.
(c) Connect flex lines to HCU. Start lines by
hand to avoid cross threading.
(8) Swing rear brakeline around and connect it to
master cylinder. Then install and connect frontbrakeline to combination valve and master cylinder.
Start brakelines by hand to avoid cross threading.
(9) Tighten combination valve bracket attaching
nut to 25 Nzm (220 in. lbs.) torque.
(10) Install S-clip on lines from master cylinder to
combination valve.
(11) Connect wire to pressure differential switch in
combination valve.
(12) Fill and bleed brake system.
(13) Tighten brakeline fittings to 15-18 Nzm (130-
160 in. lbs.) at HCU and master cylinder and to
18-24 Nzm (160-210 in. lbs.) at combination valve.
(14) Connect brake booster and canister vacuum
hoses to manifold fittings.
(15) Install air cleaner housing, filter, cover, and
hose.
(16) Connect PCV hose.MASTER CYLINDER BENCH BLEEDING
The bench bleeding procedure for both master cyl-
inder types is basically the same. The only difference,
is that both bleed tubes go in the same filler neck
opening on cylinders with the nylon reservoir.
(1) On models with integral master cylinder, fill
each reservoir to within 6 mm (1/4 in.) of rim. On
two-piece cylinder, fill reservoir to FULL mark.
(2) Fabricate and install master cylinder bleed
tubes. Be sure tube ends are submerged in brake
fluid. Tubes can be fabricated from rubber hose, or
copper tubing and spare brakeline fittings.
(3) Using push rod or wooden dowel (Fig. 26),
stroke cylinder pistons fully into bore;then allow pis-
tons to return under spring pressure. Repeat this op-
eration until air bubbles cease to appear in fluid.
(4) Remove bleed tubes, cap outlet ports, and in-
stall reservoir cap, or cover and seal.
Fig. 24 Master Cylinder Installation
Fig. 25 Combination Valve Installation
Fig. 26 Typical Method Of Bleeding Master Cylinder
(One-Piece Cylinder Shown)
JMASTER CYLINDERÐCOMBINATION VALVE 5 - 21