JEEP CHEROKEE 1988 Service Repair Manual
Page 331 of 1378
Remove axle shaft oil seal from axle housing tube.
3) Place axle shaft in a vise. Drill a 1/4" (6.35 mm) hole
3/4 of the way through bearing retaining ring. Chisel off bearing
retaining ring. Do not use a torch. Press bearing off axle. Remove
seal and retainer plate.
Installation
Lubricate bearing and seal lip. Install retainer plate and
seal over axle. Press axle shaft bearing and retaining ring on shaft
simultaneously. Ensure bearing and ring are seated against axle shaft
shoulder. To complete installation, reverse removal procedure to
complete installation.
WHEEL CYLINDER
Removal
Remove wheel assemblies, brake drums and brake shoes.
Disconnect brake line at wheel cylinder. Do not bend brake line away
from cylinder. Remove cylinder-to-support plate bolts. Remove
cylinder.
Installation
To install, reverse removal procedure. Start brake line
fitting into cylinder before installing cylinder to support plate.
OVERHAUL
DISC BRAKE CALIPER
Disassembly
1) Clean caliper exterior with brake cleaning solvent. Drain
residual fluid from caliper and place caliper on a clean working
surface.
2) Remove piston from caliper by applying compressed air to
inlet port. Use just enough pressure to ease piston out of bore.
Protect piston from damage with folded shop towels. Do not try to
catch piston by hand.
3) Pry dust boot out of bore with screwdriver. Do not scratch
bore. Using a small plastic or wooden stick, pry piston seal from
bore. See Fig. 11. Remove bleeder screw, sleeves, and bushings.
Cleaning & Inspection
Clean all parts with brake cleaning solvent. Blow dry parts.
Check for damaged or worn parts. Stains on piston bore can be polished
with crocus cloth. Do not use emery cloth or any other abrasive.
Reassembly
1) Lubricate bore and new seal with brake fluid. Install seal
in groove using fingers. Lubricate piston with brake fluid. Slide
metal retainer portion of dust boot over open end of piston. Pull boot
rearward until boot lip seats in piston groove.
2) Push retainer portion of dust boot forward until boot is
flush with rim at open end of piston and boot fold snaps into place.
Insert piston in bore being careful not to unseat piston seal.
3) Push piston to bottom of bore using hammer handle.
Position dust boot retainer in counterbore at top of piston bore. Seat
dust boot retainer with Dust Boot Installer (J-22904 or J-33028).
Reverse removal procedure to complete installation.
Page 332 of 1378
Fig. 11: Caliper Assembly (Grand Wagoneer)
Courtesy of American Motors/Jeep Corp.
Fig. 12: Caliper Assembly (Except Grand Wagoneer)
Courtesy of American Motors/Jeep Corp.
MASTER CYLINDER - EXCEPT GRAND WAGONEER
Page 333 of 1378
NOTE: Do not hone master cylinder. Bore has a highly polished
"Bearingized" surface. Honing will cause premature failure
of rubber parts.
Disassembly
1) Remove reservoir cover and diaphragm. Drain remaining
brake fluid. Push in on primary piston and remove snap ring.
2) Carefully apply compressed air at forward brake line hole
while plugging rear hole. Use caution as piston will be forced out
open end of master cylinder with considerable force.
3) Remove spring retainer and seals from secondary piston.
Discard seals. Clamp mounting ear of master cylinder in vise and
carefully pry off reservoir.
4) Do not attempt to remove take-up valve from master
cylinder as it is not a serviceable component. Remove reservoir
grommets and discard.
Inspection
Inspect cylinder bore for scoring or corrosion. If signs of
corrosion are evident, replace master cylinder. Use no abrasives on
cylinder bore. Inspect reservoir cover and diaphragm for cuts, cracks
or deformation. Replace damaged or defective parts as necessary.
Reassembly
1) Lubricate new reservoir grommets with clean brake fluid
and press into master cylinder. Ensure grommets are properly seated.
Lay reservoir on flat, hard surface. Rock master cylinder body onto
reservoir until completely seated.
2) Lubricate new piston seals with clean brake fluid and
install on secondary piston, with lip of seals toward ends of piston.
Install spring retainer.
3) Install secondary piston spring and secondary piston
assembly in master cylinder. Lubricate primary piston seals with clean
brake fluid.
4) Install primary piston in master cylinder. Press in piston
and install snap ring. Fit diaphragm in reservoir cover and install
cover.
Fig. 13: Exploded View of Quick Take-Up Master Cylinder
Courtesy of General Motors Corp.
Page 334 of 1378
MASTER CYLINDER - GRAND WAGONEER
NOTE: Do not hone master cylinder bore. Bore has a highly polished
"bearingized" surface. Honing will cause premature failure
of rubber parts.
Disassembly
1) Clean outside of cylinder thoroughly and remove cover.
Drain fluid. Pump piston to remove any remaining fluid. On
Delco/Moraine models with composite fluid reservoir, install metal
flange in vise and pry reservoir off with a pry bar. Bendix composite
reservoir is held on by 4 bolts on bottom of reservoir. On manual
brake models, remove boot from cylinder to uncover push rod retainer.
2) Pry up retainer tab to release retainer. Remove snap ring
from groove in cylinder bore. Remove both piston assemblies. Remove
remaining internal parts from bore. Note direction of piston seals.
Remove and discard all rubber parts from piston assemblies.
3) Tube seats can be removed if damaged. Enlarge holes in
tube seats using a 13/64" drill. Place a large flat washer over outlet
and thread a 1/4" x 20 x 3/4" screw into seat. Tighten screw until
seat is loose. See Fig. 14. Remove seat, screw and washer.
Fig. 14: Removing Tube Seat from Master Cylinder
Courtesy of American Motors/Jeep Corp.
Inspection
Inspect cylinder bore for scoring or corrosion. Staining
Page 335 of 1378
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
Page 336 of 1378
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
Page 337 of 1378
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Application In. (mm)
Cherokee, Comanche, Wagoneer & Wrangler
Drum Diameter ............................ 10.00 (254.0)
Drum Width ................................. 1.75 (44.5)
Max. Drum Refinish Diam. ................. 10.06 (255.5)
Wheel Cyl. Diameter ........................ .875 (22.2)
Master Cyl. Diameter ....................... .937 (23.8)
Grand Wagoneer
Drum Diameter ............................ 11.00 (279.4)
Drum Width ................................. 2.00 (50.8)
Max. Drum Refinish Diam. ................. 11.06 (280.9)
Wheel Cyl. Diameter ....................... .937 (23.80)
Master Cyl. Diameter ..................... 1.125 (28.58)
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Page 338 of 1378
CEC C O M PO NEN T R EM OVA L & IN STA LLA TIO N
1988 J e ep C hero ke e
1984-86 Computerized Engine Controls
JEEP 4-CYLINDER COMPUTERIZED ENGINE CONTROL
COMPONENT REMOVAL & INSTALLATION
Cherokee, CJ/Scrambler, Comanche, Wagoneer, Wrangler
MICROCOMPUTER CONTROL UNIT (MCU) R & I
The MCU is located behind the right front kick panel. Remove
MCU mounting bolts and disconnect wiring harness connector. Do not
bend connector pins when removing. Reconnect harness to MCU and
replace mounting bolts.
MIXTURE CONTROL (M/C) SOLENOID R & I
Remove air cleaner and disconnect solenoid harness connector.
Remove retaining screws and remove solenoid from carburetor. Coat
rubber seal, on end of solenoid stem, with silicone grease or light
engine oil prior to reinsertion. Using a new gasket, replace solenoid.
Reconnect wiring harness and replace air cleaner.
Fig. 1: M/C Solenoid Location on Carburetor
OXYGEN (O2) SENSOR R & I
Page 339 of 1378
Disconnect wire connector from oxygen sensor. Remove sensor
from exhaust manifold. Clean threads in manifold. Coat threads of
replacement sensor with anti-seize compound. Install new sensor in
exhaust manifold and tighten to 32-38 ft. lbs. (43-51 N.m). Reconnect
wire connector.
Page 340 of 1378
CLU TC H
1988 J e ep C hero ke e
1988 Clutch
Hydraulic
Cherokee, Comanche, Wagoneer, Wrangler
DESCRIPTION
The clutch assembly consists of a single dry-disc driven
plate and a one-piece diaphragm spring-type clutch cover. On Wrangler
4-cylinder models, the clutch cover and driven plate diameter is 9.28"
(232 mm). On Wrangler 6-cylinder models, the clutch cover and driven
plate diameter is 10.5" (266 mm). On all other 4 and 6-cylinder
models, the clutch cover and driven plate diameter is 9.7"
(246 mm). The clutch is actuated through a hydraulic master cylinder
and slave cylinder.
On Wrangler models, the slave cylinder is mounted inside the
clutch housing. The bearing is permanently attached to the cylinder
piston.
TRANSMISSION APPLICATION
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Vehicle Model Transmission Model
Cherokee, Comanche, Wagoneer ........... Aisin AX4 4-Speed
Aisin AX5 5-Speed O/D
Wrangler ........................... Aisin AX5 5-Speed O/D
Peugeot BA 10/5 5-Speed O/D
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REMOVAL & INSTALLATION
TRANSMISSION
Removal
1) Remove the shift knob and lock nut from transmission and
transfer case shift levers (if equipped). On Wrangler models, remove
screws attaching transmission and transfer case shift lever boots and
remove both boots.
2) On all other models, raise outer gearshift lever boot and
remove upper part on center console. Remove lower part of console,
remove inner boot and gearshift lever.
3) On Wrangler models, remove transmission shift tower dust
cover. Remove transmission shift lever and stub shaft. DO NOT remove
shift lever from stub shaft.
4) On all models, raise and support vehicle. Drain
transmission lubricant. Mark rear drive shaft for reassembly and
remove rear drive shaft. Support transmission assembly and remove
crossmember. Disconnect speedometer cable and wiring from back-up
light switch.
5) On 4WD models, drain transfer case lubricant. Disconnect
transfer case vacuum hoses and linkage. Tag vacuum hoses for
reassembly. Disconnect front drive shaft and secure out of way.
6) On all models, remove clutch slave cylinder. Position
transmission jack under transmission assembly. Remove bolts securing
clutch housing to engine and remove transmission assembly. Remove
throw-out lever, bearing, and pivot ball from clutch housing.
Installation
To install, reverse removal procedure.