JEEP CHEROKEE 1988 Service Repair Manual

CLUTCH
Removal
Remove transmission assembly. Mark position of clutch cover
on flywheel for reassembly reference. Evenly loosen clutch cover bolts
one or 2 turns at a time until clutch cover spring tension is
released. Remove cover bolts, clutch cover, and disc. See Fig. 1.
Installation
1) Check all components for wear or damage and replace as
necessary. Using clutch alignment tool, align clutch disc and loosely
install clutch cover. Be sure marks made during removal are aligned.
2) To avoid warping clutch cover, tighten each cover bolt a
few turns at a time. To complete installation, reverse removal
procedure.
Fig. 1: Exploded View Of Cherokee, Comanche & Wagoneer Hydraulic
Clutch Assembly
Wrangler has a one-piece slave cylinder.
CLUTCH MASTER CYLINDER
Removal
1) Disconnect hydraulic line at master cylinder. Plug
openings to prevent dirt from entering system. Remove cotter pin and
washer holding cylinder push rod on clutch pedal.
2) Slide push rod off pedal pivot. Remove nuts attaching
clutch master cylinder to studs on dash panel and remove cylinder.
Installation
To install, reverse removal procedure. Bleed hydraulic
system.

CLUTCH SLAVE CYLINDER
Removal (Wrangler)
1) Disconnect slave cylinder inlet line. Remove transmission
and transfer case. Slide rubber insulator off slave cylinder lines.
Remove bolts attaching insulator bracket to clutch housing. Slide
bracket off cylinder lines.
2) Remove slave cylinder and bearing retaining nut. Pry nut
up and off mounting pin on transmission front case. Remove slave
cylinder and bearing by sliding assembly off transmission input shaft.
See Fig. 2 .
Installation
To install, reverse removal procedure. Bleed hydraulic
system.
Fig. 2: Wrangler Clutch Slave Cylinder
Courtesy of Chrysler Motors.
Removal (Cherokee, Comanche & Wagoneer)
Disconnect hydraulic line at clutch slave cylinder. Cap line
to prevent fluid loss. Remove spring holding clutch fork lever to
cylinder push rod. Remove bolts attaching slave cylinder to clutch
housing. Remove slave cylinder, heat shield, clutch fork pivot, washer
and seal.
Installation
To install, reverse removal procedure. Bleed hydraulic
system.
PILOT BUSHING

Removal (Cherokee, Comanche & Wagoneer)
Remove clutch assembly. Remove pilot bushing using Slide
Hammer (J-2619-01) and Bushing Remover (J-5822).
Installation
Lubricate replacement bushing with engine oil. Remove pilot
bushing lubricating wick and soak wick in engine oil. Install wick in
bushing bore. Install bushing using Clutch Pilot Shaft (J-33169). Keep\
pilot shaft parallel with crankshaft center line to prevent damage to
bushing. Reverse removal procedure to complete installation.
OVERHAUL
CLUTCH MASTER CYLINDER
Disassembly
1) Remove reservoir cap and cover. Remove push rod dust
cover. Remove snap ring holding push rod in cylinder bore. Discard
dust cover and snap ring.
2) Remove push rod, retaining washer, and seal as an
assembly. Discard seal. Remove plunger, valve spring, and valve stem
assembly from cylinder bore by tapping cylinder body on wood block.
3) Compress valve spring slightly. Pry tab of valve stem
retainer upward to release retainer, spring and stem assembly from
plunger. Remove seal from plunger and discard. Remove spring retainer
and valve stem from valve spring.
NOTE: Retainer tab is located in rectangular slot in side of stem
retainer.
4) Remove valve stem from retainer. Remove spring washer and
stem tip seal from end of valve stem. See Fig. 3. Discard stem tip
seal and spring washer. Clean parts with brake fluid or brake cleaning
solvent.
5) Inspect cylinder bore for wear, nicks or scores. Master
cylinder bore must be clean and smooth. Light discoloration is
acceptable. Replace if necessary. Clutch master cylinder must not be
honed under any circumstances.
Fig. 3: Exploded View Of Clutch Master Cylinder
Courtesy of Chrysler Motors.
Reassembly
1) Lubricate cylinder bore with brake fluid. Make sure lip of

plunger seal faces stem end of plunger. Install stem tip seal so seal
shoulder fits in undercut at end of valve stem.
2) End of valve stem should pass through stem retainer and
seat in small bore in end of plunger. Bend retainer tab downward to
lock stem and retainer on plunger. To complete assembly, reverse
disassembly procedures.
CLUTCH SLAVE CYLINDER
Disassembly
NOTE: On Wrangler models, the integral slave cylinder and throw
out bearing assembly is not serviceable. If cylinder,
bearing or lines become damaged the entire assembly must be
replaced.
1) Clean cylinder exterior. Remove dust boot from cylinder.
Remove cylinder push rod, plunger and spring as an assembly. Remove
spring seal from plunger.
2) Remove snap ring holding push rod in plunger. Remove push
rod and boot. Remove boot from push rod. See Fig. 4. Clean parts with
brake fluid or brake cleaning solvent. Inspect cylinder bore for wear,
nicks or scores. Replace if necessary.
Fig. 4: Exploded View Of Clutch Slave Cylinder
Courtesy of Chrysler Motors.
Reassembly
Reverse disassembly procedure. Lubricate cylinder bore and
seal with brake fluid before reassembly.
HYDRAULIC SYSTEM BLEEDING
1) Fill master cylinder reservoir with DOT 3 brake fluid. On
all models except Wrangler, compress slave cylinder plunger by pushing
release lever as far forward as possible.
2) Attach rubber hose to slave cylinder bleeder screw.
Immerse other end of hose in glass container 1/2 full of brake fluid.
Loosen bleeder screw and have an assistant depress clutch pedal.
Tighten bleeder screw and release pedal.
3) Repeat bleeding procedure until fluid entering container
is free of bubbles. DO NOT allow reservoir to run out of fluid during

bleeding. Refill clutch master cylinder to level mark on reservoir.
TORQUE SPECIFICATIONS
TORQUE SPECIFICATIONS TABLE








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Application Ft. Lbs. (N.m)
Cherokee, Comanche & Wagoneer
Bellhousing-to-Engine Bolts .................... 28 (38)
Clutch Cover Bolts ............................. 23 (31)
Crossmember-to-Sill Bolts ...................... 30 (41)
Flywheel Bolts
4-Cylinder .............................. ( 1) 50 (68)
6-Cylinder ............................ 61-75 (83-102)
Master Cylinder Attaching Nuts ................. 19 (26)
Rear Support-to-Engine Bolt .................... 33 (45)
Slave Cylinder-to-Clutch
Housing Bolts .................................. 16 (22)
Transmission Drain Plug ........................ 27 (37)
Wrangler
Bellhousing-to-Engine Bolts .................... 28 (38)
Clutch Cover Bolts
4-Cylinder .................................... 23 (31)
6-Cylinder .................................... 40 (54)
Crossmember-to-Sill Bolts ...................... 30 (41)
Master Cylinder Attaching Nuts ................. 19 (26)
Rear Support-to-Crossmember Bolts .............. 33 (45)
Transmission Drain Plug ........................ 27 (37)
( 1) - Plus additional 60 degrees turn after reaching
torque specification.









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CO M PU TE R R ELE A R N P R O CED URES

1988 J e ep C hero ke e
GENERAL INFORMATION
Computer Relearn Procedures
All Models
* PLEASE READ THIS FIRST *
The following general procedures are to be used if
driveability problems are encountered after power loss or battery has
been disconnected. These procedures may provide an aid in eliminating
these problems.
To reduce the possibility of complaints, after any service
which requires battery power to be disconnected, vehicle should be
road tested.
COMPUTER RELEARN PROCEDURES
Vehicles equipped with engine or transmission computers may
require a relearn procedure after vehicle battery is disconnected.
Many vehicle computers memorize and store vehicle operation patterns
for optimum driveability and performance. When vehicle battery is
disconnected, this memory is lost. The computer will use default data
until new data from each key start is stored. As computer memorizes
vehicle operation for each new key start, driveability is restored.
Vehicle computers may memorize vehicles operation patterns for 40 of
more key starts.
Customers often complain of driveability problems during
relearn stage because vehicle acts differently then before being
serviced. Depending on type and make of vehicle and how it is
equipped, the following complaints (driveability problems) may exist:
* Harsh Or Poor Shift Quality
* Rough Or Unstable Idle
* Hesitation Or Stumble
* Rich Or Lean Running
* Poor Fuel Mileage
These symptoms and complaints should disappear after a number
of drive cycles have been memorized. To reduce the possibility of
complaints, after any service which requires battery power to be
disconnected, vehicle should be road tested. If a specific relearn
procedure is not available, the following procedure may be used:
Automatic Transmission
* Set parking brake, start engine in "P" or "N" position.
Warm-up vehicle to normal operating temperature or until
cooling fan cycles.
* Allow vehicle to idle for one minute in "N" position. Select
"D" and allow engine to idle for one minute.
* Accelerate at normal throttle position (20-50%) until vehicle
shifts into top gear.
* Cruise at light to medium throttle.
* Decelerate to a stop, allowing vehicle to downshift, and use
brakes normally.
* Process may be repeated as necessary.
Manual Transmission

* Place transmission in Neutral position.
* Ensure emergency brake has been set and all accessories
are turned off.
* Start engine and bring to normal operating temperature.
* Allow vehicle to idle in Neutral for one minute.
* Initial relearn is complete: process will be completed during
normal driving.
Some manufacturers identify a specific relearn procedure
which will help establish suitable driveability during relearn stage.
These procedures are especially important if vehicle is equipped with
and electronically controlled automatic transmission or transaxle.
Always complete procedure before returning vehicle to customer.

CO OLIN G S YSTE M S PEC IF IC ATIO NS

1988 J e ep C hero ke e
1988 ENGINE COOLING
Jeep Cooling System Specifications
Cherokee, Comanche, Wagoneer, Wrangler, Grand Wagoneer
MAINTENANCE SCHEDULE
Change engine coolant every 12,500 miles or 12 months.
Thereafter change engine coolant at the beginning of every winter
season. Maintain ethylene glycol and water solution at a mixture of
50/50.
COOLING SYSTEM SPECIFICATIONS TABLE









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Application Capacity
Quarts(L)
2.5L
Thermo. Temp.
F (C) ............ 192-198 (89-92)
Rad. Cap PSI ............................... 12-15
Coolant Capacity Qts. (L) ........... ( 1) 10 (9.4)
4.0L
Thermo. Temp.
F (C) ............ 192-198 (89-92)
Rad. Cap PSI ............................... 12-15
Coolant Capacity Qts. (L) .............. 12 (11.3)
4.2L
Thermo. Temp.
F (C) ............ 192-198 (89-92)
Rad. Cap PSI ............................... 12-15
Coolant Capacity Qts. (L) ......... ( 2) 10.5 (9.9)
6.0L
Thermo. Temp.
F (C) ............ 192-198 (89-92)
Rad. Cap PSI ............................... 12-15
Coolant Capacity Qts. (L) .......... 14 (14 (13.2)
( 1) - Without A/C 23 qts. (2.1L) for recovery tank.
( 2) - Includes 1 qt. (.9L) for recovery tank.









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CRUIS E C O NTR O L S YSTE M

1988 J e ep C hero ke e
1988 Cruise Control Systems
JEEP CRUISE COMMAND
All Models
DESCRIPTION & OPERATION
Jeep vehicles use an electro-mechanical servo system. The
system consists of a control module, speed sensor, servo, control
switch assembly, vacuum storage canister, check valve and release
system. Release system consists of a mechanical vacuum vent valve and
brake and clutch (M/T) release switches.
Cruise control switch is an integral part of turn signal
switch lever and consists of 2 separate switches. First is an "ON-OFF"
and "RESUME" slide switch located on flat of directional switch lever.
Second is "SET/COAST" push button switch located at end of
directional switch lever. To engage system, move slide switch to "ON"
position and accelerate to desired speed. Depress and release
"SET/COAST" button on end of switch lever. System will now maintain
selected speed.
System will automatically disengage when brake or clutch
pedal is depressed. It can be re-engaged to previously selected speed
by accelerating to 30 MPH and moving slide switch to "RESUME"
position, then releasing switch.
NOTE: When slide switch is moved to "OFF" position, pre-set speed
of "RESUME" function is canceled from memory and must be
reset when system is reactivated.
Higher speed can be set by pressing on accelerator pedal
until new speed is reached and then pushing "SET/COAST" button. Lower
speed can be obtained by lightly depressing brake pedal, allowing the
vehicle to slow to desired speed and then depressing and releasing
"SET/COAST" button.
CONTROL MODULE
Control module receives input voltage representing vehicle
speed from speed sensor, which is driven by the speedometer cable.
Control module has a low speed circuit that prevents operation at
speeds below 30 MPH. See Fig. 1.
SERVO
Servo is controlled by control module and uses manifold
vacuum to control throttle. Bead-link chain connects servo cable to
throttle linkage. See Fig. 1.
CONTROL SWITCH
Control switch assembly is an integral part of turn signal
switch lever. See Fig. 1.
RELEASE SYSTEM
Release system deactivates cruise control system when brake
or clutch pedal is depressed. Either servo vent valve or mechanical
vacuum vent switch admits atmospheric pressure into servo when brake
pedal is depressed.

Fig. 1: Cruise Control System Components
Courtesy of Chrysler Motors.
TROUBLE SHOOTING
NOTE: Vehicles with computerized engine controls, should be tested
for stored computer codes. Codes and related problems must
be repaired prior to cruise control diagnosis and repair.
For additional information, see COMPUTERIZED ENGINE CONTROLS
section.