1988 JEEP CHEROKEE brakes

Fig. 3: Back View of Valve Shaft
PARKING BRAKE - EXCEPT GRAND WAGONEER
1) Adjust rear brakes. Check cable for binds, kinks or frayed
condition. Replace cable (if necessary). Apply and release parking
brake 5 times.

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.

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.

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

guide, adjuster screw assembly, parking brake lever and lever pivot
pin with molybdenum disulphide grease.
2) Connect parking brake lever to secondary brake shoe with
washer and "U" clip. Crimp ends of clip to secure clip on pivot.
Remove wheel cylinder clamp. Position brake shoes on brake support
plate and install hold-down springs.
3) Install parking brake lever strut and spring. Install
adjuster cable guide plate and adjuster cable on anchor pin. Install
primary return spring. Install guide to secondary brake shoe. Install
secondary return spring.
4) Install adjuster screw, spring and lever. Connect lever to
cable. Using Brake Gauge (J-21177-01), preset brake shoe adjustment.
Install brake drums. Adjust brake shoes with drum in place.
5) Install wheels and lower vehicle. To adjust and balance
brake system, apply and release brakes 10-15 times while driving
forward and backward. Road test vehicle.
DRUM BRAKE SHOES - GRAND WAGONEER
Removal
1) Raise vehicle and support with safety stands. Remove
wheels. On models with full-floating rear axle, remove 2 screws that
retain drum on hub.
2) On all models, remove primary shoe return spring,
automatic adjuster actuator spring and secondary shoe return spring.
Remove hold-down springs. Remove brake shoe assemblies. See Fig. 10.
3) Disengage parking brake cable from parking brake lever.
Remove parking brake strut and brake shoe assembly as a unit. Place
wheel cylinder clamps over cylinders in order to retain pistons.
4) Inspect automatic adjuster lever and pivot, actuating
lever, parking brake lever, automatic adjuster and springs. Replace
weak springs, bent levers and parts that are worn or broken.
Fig. 10: Exploded View of Drum Brake Assembly (Grand Wagoneer)
Courtesy of American Motors/Jeep Corp.
Installation
1) Clean support plate. Apply a thin film of molybdenum

disulphide grease or chassis lubricant on support plate ledges, anchor
pin, adjuster screw threads and pivot.
2) Apply grease to adjuster lever-to-secondary brake shoe
contact surface, parking brake lever pivot and portion of lever that
contacts secondary brake shoe.
3) Attach parking brake cable to parking brake lever on
secondary shoe. Pinch "U" clip to retain lever on shoe. Install
secondary brake shoe, automatic adjuster lever and lever pivot as an
assembly.
4) Install brake shoe hold-down spring. Install return spring
on actuating lever tang. Large end of tapered spring should rest on
brake shoe.
5) Install primary shoe and hold-down spring. Install guide
plate on anchor pin. Install parking brake strut and spring on brake
shoes.
6) Install adjusting screw and spring. Short end of hooked
spring attaches to primary brake shoe. Long hooked end attaches to
secondary brake shoe.
7) Install secondary shoe return spring, adjuster spring and
primary return spring. Install brake drums. Adjust brakes. Bleed brake
system.
8) Install wheels and lower vehicle. Apply and release brakes
10-15 times while driving forward and backward to adjust and balance
brake system. Road test vehicle.
MASTER CYLINDER - EXCEPT GRAND WAGONEER
Removal
1) With engine off, depress brake pedal several times to
release vacuum in power unit. Clean dirt and grease from brake line
connections.
2) Disconnect and plug brake lines at master cylinder. Remove
retaining nuts and master cylinder.
Installation
To install, reverse removal procedure. Bleed brake system.
See BRAKE SYSTEM BLEEDING in this article.
MASTER CYLINDER - GRAND WAGONEER
Removal
Disconnect brake lines at master cylinder and plug. On
vehicles without power assist units, disconnect brake pedal push rod
at brake pedal. Remove master cylinder retaining nuts at firewall.
Remove master cylinder.
Installation
1) Master cylinder should be bench bled before installation.
See BRAKE SYSTEM BLEEDING in this article. Position master cylinder on
vehicle. Loosely install retaining nuts. Loosely install brake lines
to cylinder. Tighten retaining nuts. Tighten brake lines.
2) Connect brake pedal push rod (if removed). Fill reservoir\
with brake fluid and bleed brake system. See BRAKE SYSTEM BLEEDING in
this article.
REAR AXLE BEARING & SEAL
Removal
1) Raise vehicle and support with safety stands. Remove wheel
assembly and brake drum. Remove support plate retaining nuts through
hole provided in axle flange. Use a slide hammer to remove axle shaft.
2) If wheel bearing cup remains in housing, use Slide Hammer
(J-2619-01) and Bearing Remover (J-26941) to remove bearing cups.

which has not pitted or roughened surface of cylinder can be removed
with crocus cloth. If cylinder bore is scored, pitted or corroded,
replace master cylinder.
Reassembly
1) Install replacement tube seats by threading a spare brake
line tube nut into hole. Turn nut in until tube seat bottoms. Do not
cock tube seat in hole. Remove nut and check for burrs which may have
been loosened by nut. Install secondary seals on secondary piston,
with cup lips facing away from each other.
2) Install primary seal, spring retainer and return spring on
secondary piston. Install seal so lip faces interior of master
cylinder when installed. Lubricate cylinder bore with clean brake
fluid and install secondary piston assembly. Lubricate primary piston
seals and install primary piston assembly in bore. Hold primary piston
downward in bore and install snap ring.
3) Install composite reservoir (if equipped). On models with\
push-on composite fluid reservoir, invert reservoir, install grommets
and press on body using a rocking motion. Install master cylinder
cover and new diaphragm.
4) On vehicles with manual brakes, assemble brake pedal push
rod through retainer (if equipped). Push retainer over end of master
cylinder and install rubber boot.
Fig. 15: Exploded View of Master Cylinder (Grand Wagoneer)
Courtesy of American Motors/Jeep Corp.
WHEEL CYLINDER

Disassembly
Remove dust boots. Push pistons, piston cups and expander
spring out of bore. Discard cups. Clean all parts with brake solvent.
Inspect cylinder bore and piston for pitting, wear or damage. Replace
as necessary. Light scoring or pitting may be removed by honing.
Reassembly
1) Lubricate cylinder bore and internal components with brake
fluid. Do not lubricate dust boots. Position replacement piston cups
on spring expanders. Install assembled parts in cylinder bore.
2) Ensure expanders are seated in piston cups. Cups are to be
installed with lips facing each other. Install pistons with flat sides
facing interior of bore. Install dust boots.
TORQUE SPECIFICATIONS
TORQUE SPECIFICATIONS TABLE








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Application Ft. Lbs. (N.m)
Disc Brakes
Caliper Mounting Bolts ......................... 35 (47)
Bleeder Screw .................................. 12 (16)
Brake Line-to-Caliper .......................... 13 (18)
Drum Brakes
Wheel Cylinder Bolts ........................... 11 (15)
Bleeder Screw 1/4" ........................... 4-5 (5-7)
Bleeder Screw 3/8" ......................... 4-10 (5-14)
Brake Line ............................... 10-17 (14-23)
Backing Plate Bolt ....................... 30-40 (41-54)
Master Cylinder Retaining Nuts
Except Grand Wagoneer .......................... 20 (27)









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BRAKE SYSTEM SPECIFICATIONS
DISC BRAKE SPECIFICATIONS
DISC BRAKE SPECIFICATIONS TABLE








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Application In. (mm)
Cherokee, Comanche, Wagoneer & Wrangler
Disc Diameter ............................ 11.02 (279.9)
Lateral Runout ............................ 0.005 (0.13)
Parallelism ............................... 0.001 (0.03)
Original Thickness ......................... 0.88 (22.4)
Min. Refinish Thickness .................. 0.815 (20.70)
Discard Thickness ........................ 0.815 (20.70)
Grand Wagoneer
Disc Diameter ............................ 12.00 (304.8)
Lateral Runout ............................ 0.005 (0.13)
Parallelism ............................... 0.001 (0.03)
Original Thickness ................................. N/A
Min. Refinish Thickness .................. 1.215 (30.86)
Discard Thickness ........................ 1.215 (30.86)









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DRUM BRAKE SYSTEM SPECIFICATIONS
DRUM BRAKE SPECIFICATIONS TABLE