1988 JEEP CHEROKEE parking brake

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

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.

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

lubricant to axle flange bearing bore and install axle.
YOKE & PINION OIL SEAL
Removal
1) Raise and support vehicle. Remove wheels and brake drums.
Mark and remove drive shaft. Using an INCH lb. torque wrench, record
torque required to rotate pinion several revolutions.
2) Hold yoke from turning and remove pinion nut. Mark drive
pinion shaft and yoke for reassembly reference. Remove yoke and pinion
oil seal.
Installation
1) Coat new seal with rear axle lubricant and install. Align
marks made at disassembly and install yoke. Install new pinion nut and
tighten just enough to remove end play.
CAUTION: DO NOT overtighten pinion nut. If desired preload is
exceeded, a new collapsible pinion spacer sleeve must be
installed and drive pinion preload reset.
2) Using an INCH lb. torque wrench, check torque required to
turn pinion. Refer to torque reading recorded during disassembly and
add 5 INCH lbs. (.6 N.m) for correct preload. Tighten pinion nut
slightly and recheck preload. Repeat procedure until desired preload
is obtained.
REAR AXLE ASSEMBLY
Removal
1) Raise and support vehicle. Remove wheels and brake drums.
Disconnect brake hose-to-axle connection and plug line.
2) Disconnect parking brake cable at brake equalizer. Mark
and remove drive shaft. Disconnect track bar at axle bracket (if
equipped). Remove axle vent tube at axle. Support axle assembly.
Remove spring "U" bolts and tie plates.
3) Loosen, but do not remove, bolts which attach front of
rear spring to frame brackets. Lift axle to relieve axle weight from
springs and remove bolts retaining springs to shackles. Lower springs
to floor. Lower jack and remove axle assembly.
NOTE: Factory axles are shipped without lubricant. When adding
lubricant, position axle horizontally with yoke end of
pinion housing facing downward. Turn pinion shaft several
times to lubricate bearings.
Installation
1) To install, support axle assembly with jack and slide axle
into place. Raise, align and install spring-to-frame and shackle
bolts. Tighten spring-to-frame and shackle bolts to 111 ft. lbs. (150
N.m). Install brake hose, axle vent tube and parking brake cable.
Align and connect drive shaft.
2) Bleed hydraulic system and adjust parking brake cable.
Ensure axle is filled with 75-90W gear lubricant. Ensure spring
centering bolt heads are seated in axle spring seat before tightening
"U" bolts.
OVERHAUL
DISASSEMBLY
NOTE: It is not necessary to remove axle assembly from vehicle to

Automatic Load Leveling Sw. On compressor bracket, in
engine compartment.
Back-Up Light Sw. (Man. Trans.) On left side of transmission
case.
Back-Up/Neutral Sw. (Auto. Trans.) On left side of transmission
case.
Brake/Stop Light (Cruise) Switch On brake pedal bracket.
Brake Warning Switch On brake pressure differential
valve, below master cylinder.
Closed Throttle (Idle) Switch An integral part of ISA motor.\
Command Track Switch On left side of transmission.
Parking Brake Switch Under center console, at base
of parking brake lever.

1) Disconnect wire harness connector from CTS sensor. Test
resistance of sensor with a high impedance digital ohmmeter.
Resistance should be less than 1000 ohms with engine warm. See
TEMPERATURE-TO-RESISTANCE VALUES table.
2) Test resistance of wire harness between ECU terminal D-3
and sensor connector terminal. Repeat test at terminal C-10 of ECU
and sensor connector terminal. Repair wire harness if an open circuit
is indicated.
MAT Sensor Test
1) Disconnect wire harness connector from MAT sensor. Test
resistance of sensor with a high impedance digital ohmmeter.
Resistance should be less than 1000 ohms with engine warm. Replace
sensor if resistance is not within specified range. See
TEMPERATURE-TO-RESISTANCE VALUES table.
2) Test resistance of wire harness between ECU wire harness
connector terminal D-3 and sensor connector terminal. Repeat test
with terminal C-8 at ECU and sensor connector terminal. Repair wire
harness if an open circuit or resistance is greater than one ohm is
indicated.
TPS Test
See THROTTLE POSITION SENSOR TEST PROCEDURE chart in this
article.
TEMPERATURE-TO-RESISTANCE VALUES (CTS & MAT SENSOR) TABLE
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F
C Ohms
(Approximate)
212 .......................... 100 ........................... 185
160 .......................... 70 ............................ 450
100 .......................... 38 ........................... 1600
70 ........................... 20 ........................... 3400
40 ............................ 4 ........................... 7500
20 ........................... -7 ......................... 13,500
0 ............................ -18 ........................ 25,000
-40 .......................... -40 ....................... 100,700
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Knock Sensor Test
1) Start engine until engine reaches normal operating
temperature. Connect Diagnostic Tester (M.S. 1700). Observe knock
value on tester. Using tip of screw driver, gently tap on cylinder
block next to knock sensor and observe knock sensor value on tester.
2) Knock sensor value should increase while tapping on
cylinder block. If knock sensor value does not increase while tapping
on cylinder block, check knock sensor for proper connection. If
connection is good, replace knock sensor.
Speed Sensor Test
Disconnect speed sensor connector from ignition control
module. Place an ohmmeter between terminals "A" and "B". (Marked on
connector) Reading should be 125-275 ohms with engine hot. Replace
sensor if readings are not within specifications.
Idle Speed Stepper (ISS) Motor
1) Set parking brake and block drive wheels. Route all
tester cables away from cooling fans, drive belts, pulleys and
exhaust system. Always allow engine speed to return to normal before
disconnecting testing tools.
2) With ignition off, disconnect ISS motor connector at

WARNING: DO NOT USE starting fluids (ether) or flammable liquids to
aid the starting of a Cummins Turbo-Diesel. NEVER pour diesel
fuel, flammable liquids or starting fluids into the air
cleaner canister, air intake or turbocharger housing in an
attempt to start the vehicle. A flash fire may result causing
personal injury.
TRANSFER CASE
CAUTION: Both drive axles are disengaged when transmission gear is
in Neutral position. Always set parking brake when leaving
vehicle unattended.
CAUTION: Never attempt to engage Low range when vehicle is moving
faster than 2-3 MPH (3-5 KM/H). Transfer case damage may
result.
GASOLINES CONTAINING ALCOHOL
CAUTION: Exclusive use of gasohol is not recommended. Vehicle test
results have shown that significant fuel system corrosion
can result when gasohol is used exclusively. Fuel additives
which are now being sold as octane enhancers are not
recommended. Most of these products contain high
concentrations of methanol.
WARRANTY INFORMATION
CAUTION: Due to the different warranties offered in various regions
and the variety of after-market extended warranties
available, please refer to the warranty package that came
with the vehicle to verify all warranty options.
BASIC NEW CAR WARRANTY
Jeep Corporation warrants to the original purchaser that the
vehicle is free from defects under normal use and service for 12
months or 12,000 miles, whichever comes first.
POWERTRAIN PROTECTION LIMITED WARRANTY
Begins at 12 months or 12,000 miles and lasts for 7 years or
70,000 miles, whichever comes first. Warranty covers Engine,
Transmission, Transfer Case, and Drive Shaft/Drive Axle(s) for RWD &
4WD.
Items not covered include, normal scheduled maintenance,
tune-ups, clutch adjustments, lack of proper maintenance, and vehicles
on which the mileage cannot readily be determined. A 100.00 deductible
on 2WD models and a 150.00 deductible on 4WD models applies to each
repair visit.
Powertrain Warranty also covers cost of towing to nearest
Jeep Dealer if vehicle cannot be driven due to failure of a covered
powertrain part.
ANTI-CORROSION PERFORATION WARRANTY
Warrants the sheet metal parts of the vehicle against
perforation (rust-through) due to corrosion. It covers any body sheet
metal panel for unlimited mileage during the first 36 months. Outer-
body sheet metal panels are covered for 7 years or 100,000 miles,