1988 JEEP CHEROKEE Service Repair Manual

1) Adjust rear brakes. Check cable for binds, kinks or frayed
condition. Replace cable (if necessary). Release parking brake. Loosen\
lock nuts at parking brake cable equalizer under vehicle.
2) Tighten cables until wheels drag slightly when rotated by
hand. Loosen equalizer until wheels rotate freely and no drag is felt.
Tighten lock nuts and check operation of parking brake.
ROTOR SERVICING
RUNOUT
1) Measure rotor lateral runout by mounting a dial indicator
on support stand or steering spindle. Position indicator stylus so it
contacts center of rotor braking surface.
2) Zero indicator and turn rotor one revolution. Note
indicator reading. Runout must not exceed specification. See DISC
BRAKE ROTOR SPECIFICATIONS table. Refinish or replace rotor (if
necessary).
NOTE: Thickness of machined rotor must not be below minimum
thickness specification.
PARALLELISM
Measure rotor parallelism with a micrometer. Measure
thickness at 4 or more equally spaced points around rotor at
approximately 1" from edge of rotor. Variation must not exceed
specification. See DISC BRAKE ROTOR SPECIFICATIONS table. Refinish or
replace rotor (if necessary).
BRAKE SYSTEM BLEEDING
Hydraulic system bleeding is necessary any time air has been
introduced into system. Bleed brakes at all 4 wheels if master
cylinder lines have been disconnected or master cylinder has run dry.
Bleed brakes with vacuum bleeding equipment, pressure bleeding
equipment or by manually pumping brake pedal while using bleeder
tubes. Always bleed brake lines in sequence. See BLEEDING SEQUENCE
table.
MASTER CYLINDER BLEEDING
Bench Bleeding
1) Master cylinder must be bled before installation to
prevent excessive amounts of air from entering the brake system,
creating poor brake operation.
2) Place master cylinder in soft-jawed vise. DO NOT tighten
vise enough to damage master cylinder. Install bleeder tubes in both
outlets of master cylinder. See Fig. 5.

Fig. 5: Bleeding Master Cylinder
Courtesy of American Motors/Jeep Corp.
3) Fill master cylinder with clean brake fluid that meets DOT
3 specifications. Ensure that the end of bleeder tubes are submerged
in the brake fluid.
4) Using proper sized rod, apply and release master cylinder
until no air bubbles exist in brake fluid flow. Once all air bubbles
are gone from master cylinder secure cap and install.
5) Bleeder tubes should be left installed on master cylinder
until master cylinder in installed. Master cylinder must be bled at
brake lines and wheels after installation.
Bleeding On Vehicle
1) Install master cylinder on vehicle after bench bleeding.
Remove bleeder lines and install brake lines. DO NOT fully tighten
brake lines at this time.
2) Slowly force brake pedal to the floor and hold in this
position. Tighten brake lines and release brake pedal. Repeat
procedure until no air bubbles exist at brake lines. Remaining wheel
cylinder or calipers may be require bleeding.
HYDRAULIC CONTROL VALVES
Hold Off Valve
1) Prior to the pressure tank bleeding procedure, the hold
off valve incorporated in the combination valve must be correctly
positioned. This allows brake fluid to flow through the combination
valve to the entire brake system.
2) The valve stem of the hold off valve may be retained using

tools available from Chrysler Motors (C-4121) or General Motors (J-
23709) during bleeding procedure. See Figs. 6 and 7. Remove valve
retainer once brake bleeding procedure is complete.
CAUTION: DO NOT use rigid clamp to position valve stem. Damage to
the valve assembly may result causing brake failure.
Fig. 6: Positioning Hold Off Valve
Courtesy of American Motors/Jeep Corp.
Fig. 7: Positioning Hold Off Valve
Courtesy of American Motors/Jeep Corp.
VACUUM BLEEDING

Fill master cylinder. Install vacuum bleed equipment to first
bleeder valve to be serviced. Open bleeder valve 3/4-1 turn. Depress
vacuum pump and pull fluid into reservoir jar. Bleed each bleeder
valve in sequence. See BLEEDING SEQUENCE table.
PRESSURE BLEEDING
1) Clean master cylinder cap and surrounding area. Remove
cap. With pressure tank at least 1/2 full, connect to master cylinder
with adapters. Attach bleeder hose to first bleeder valve to be
serviced. See BLEEDING SEQUENCE table.
2) Place other end of hose in clean glass jar partially
filled with clean brake fluid so end of hose is submerged in fluid.
The hold off valve must be positioned properly before pressure
bleeding (if equipped). See HYDRAULIC CONTROL VALVES under BRAKE
SYSTEM BLEEDING in this article.
3) Open release valve on pressure bleeder. Follow equipment
manufacturer's pressure instructions or see PRESSURE BLEEDER SETTINGS
table. Open bleeder screw 3/4-1 turn and note fluid flow.
4) Close bleeder screw when fluid flowing is free of bubbles.
Repeat procedure on remaining wheels in proper sequence. Check brake
pedal operation after bleeding has been completed.
5) Remove pressure bleeding equipment and valve retainer from
hold off valve. Ensure that master cylinder is full of fluid.
PRESSURE BLEEDER SETTINGS TABLE









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Application psi (kg/cm)
All Models ............................... 15-20 (1.1-1.4)









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MANUAL BLEEDING
NOTE: When bleeding disc brakes, air may tend to cling to caliper
walls. Lightly tap caliper, while bleeding, to aid in
removal of air.
1) Fill master cylinder. Install bleeder hose to first
bleeder valve to be serviced. See BLEEDING SEQUENCE table. Submerge
other end of hose in clean glass jar partially filled with clean brake
fluid. See Fig. 8.
2) Open bleeder valve 3/4-1 turn. Depress brake pedal slowly
through full travel. Close bleeder valve and release pedal. Repeat
procedure until flow of fluid shows no signs of air bubbles.
NOTE: When bleeding brake system manually, ensure bleeder valve is
closed when brake pedal is released.

Fig. 8: Wheel Cylinder Bleeding Procedure
Courtesy of American Motors/Jeep Corp.
BLEEDING SEQUENCE

Before bleeding system, exhaust all vacuum from power unit by
depressing brake pedal several times. Bleed master cylinder (if
equipped) with bleeder screws. Bleed slave cylinder on vehicles
equipped with remote mount power assist units. Bleed wheel cylinders
and calipers in sequence. See BLEEDING SEQUENCE table.
BLEEDING SEQUENCE TABLE









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Application Sequence
All Models ................................ RR, LR, RF, LF









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REMOVAL & INSTALLATION
DISC BRAKE CALIPER
Removal & Installation
Caliper removal and installation procedures are same as for
disc pad replacement. To remove caliper from vehicle, disconnect brake
line at caliper and cap hole to prevent contamination.
DISC BRAKE PADS
Removal
1) Drain 2/3 of brake fluid from master cylinder reservoir.
Raise vehicle and support with safety stands. Remove front wheel
assembly.
2) Place "C" clamp on caliper. Solid end of clamp should
contact back of caliper. Screw end should contact metal part of
outboard shoes.
3) Tighten "C" clamp until caliper forces piston to bottom of
bore. Remove both Allen head mounting bolts and lift caliper off
rotor. Support caliper out of the way.
4) On Grand Wagoneer, remove both brake pads from caliper.
Note spring position and support spring from inboard shoe. Remove
sleeves and bushings from caliper.
5) On all other models, hold anti-rattle clip against caliper
adapter and remove outer brake pad. Remove inner brake pad and anti-
rattle clip from caliper adapter.
Installation
1) To install, reverse removal procedure. On Grand Wagoneer,
lubricate new bushings, sleeves, bushing grooves, and small ends of
mounting bolts with silicone lubricant. Install rubber bushings in
caliper mounting ears.
2) On all other models, clean caliper mating surfaces on
adapter with a wire brush. Apply double sided adhesive tape to back
side of inner pad. Clean caliper piston surface. Lubricate caliper
mating surfaces on caliper adapter.
3) On all models, lubricate caliper mounting bolts using
brake corrosion lubricant and tighten mounting bolts. Add brake fluid
to reservoir. Apply brakes until brake pedal is firm. Check brake
fluid level.
DISC BRAKE ROTOR - WRANGLER
Removal
Raise and support vehicle. Remove front wheel and caliper.
Suspend caliper from frame or suspension. Remove rotor from hub.
Installation

Clean hub and rotor mating surfaces. To install, reverse
removal procedure.
NOTE: DO NOT disconnect brake hose from caliper unless caliper is
to be disassembled.
DISC BRAKE ROTOR - CHEROKEE, COMANCHE & WAGONEER
Removal
1) Raise and support vehicle. Remove front wheel and caliper.
Suspend caliper from frame or suspension. Remove cap, cotter pin, nut
retainer, adjusting nut and thrust washer from spindle.
2) Remove outer bearing from hub. Remove hub and rotor from
spindle. Remove hub and rotor seal. Remove inner bearing from hub.
Installation
1) Apply small amount of "EP" type waterproof wheel bearing
grease in hub cavity. Lubricate inner and outer bearings. Install
inner bearing and seal in rotor. Clean rotor surface (if necessary).
2) Install hub and rotor on spindle. Install outer bearing,
thrust washer and spindle nut. Tighten spindle nut to 17-25 ft. lbs.
(23-34 N.m) while rotating rotor to seat bearings. Loosen spindle nut
1/2 a turn and retighten an additional 19 INCH lbs (2 N.m). Reverse
removal procedure to complete installation.
DISC BRAKE ROTOR - GRAND WAGONEER
Removal
1) Raise vehicle and support with safety stands. Remove wheel
and caliper. On models without front hubs, remove rotor hub cap, drive
gear snap ring, drive gear, pressure spring and spring cup.
2) On models with front hubs, remove screws attaching hub
body to hub clutch and remove hub body from clutch. Remove large and
small retaining rings. Remove hub clutch from axle shaft.
3) On all models, remove wheel bearing outer and inner lock
nuts and retaining ring using Socket (J-6893-D). Remove rotor. Remove
wheel bearings from rotor.
Installation
1) Lubricate bearings with "EP" type waterproof wheel bearing
grease. Install bearings and seal in rotor. Install rotor and inner
lock nut. Inner lock nut has a locating peg on one side. When
installed, peg must face away from bearing.
2) Install wheel, but do not tighten lug nuts completely.
Tighten inner lock nut to 50 ft. lbs. (68 N.m) while rotating wheel.
Back of inner lock nut 1/6 turn (45-65 degrees).
3) Install retaining washer. Ensure that inner lock nut
locating peg is engaged with retaining washer. Install outer lock nut
and tighten to 50 ft. lbs. (68 N.m).
4) On models without front hubs, install pressure spring cup,
pressure spring, drive gear and snap ring. Coat rim of chrome hub
cover with Permatex No. 3 and install cap in rotor hub.
NOTE: Recessed side of spring cup faces outer bearing and flat
side faces pressure spring.
5) On models with front hubs, install hub clutch on axle.
Install large and small hub retaining rings. Install hub body on
clutch and tighten to 30 INCH lbs. (3 N.m). Reverse removal procedure
to complete installation.
DRUM BRAKE SHOES - EXCEPT GRAND WAGONEER

Removal
1) Raise vehicle and support with safety stands. Remove wheel
assembly and drum. Remove "U" clip and washer from parking brake lever
pivot pin. Place Wheel Cylinder Clamp (J-8002) over wheel cylinder.
2) Remove primary and secondary return springs, spring
retainers, hold-down springs and retaining pins. Remove adjuster
lever, adjuster screw and spring from brake shoes. Remove brake shoes.
See Fig. 9 .
Fig. 9: Exploded View of Drum Brake (W/Cable Operated Adjuster)
Courtesy of American Motors/Jeep Corp.
Installation
1) Lubricate support plate ledges, anchor pin, adjuster cable