1988 JEEP CHEROKEE boot

nuts. Install motor and WOT switch bracket assembly on throttle body.
2) Connect wiring harness connector to ISA motor and WOT
switch. Connect the throttle return spring, throttle cable and cruise
control cable. Adjust ISA motor and WOT switch. Install air cleaner
assembly.
NOTE: After replacing or reinstalling the original ISA motor, be
sure motor plunger is fully extended before starting the
engine. If plunger is not fully extended, the closed
throttle switch may open prematurely, causing idle speed to
drop to approximately 400 RPM.
3) Start engine with throttle at 1/4 open position. This
prevents ISA plunger from retracting. Stop engine. When ignition is
turned off, the motor plunger will fully extend. After installation
is complete, adjust ISA as required.
ELECTRONIC CONTROL UNIT
Removal & Installation
Locate ECU in passenger compartment, below glove box. Remove
retaining screws and mounting bracket. Remove the ECU, and disconnect
wiring harness connector from ECU. Reverse removal procedure to
install.
OXYGEN SENSOR
Removal
Disconnect the wire connector from sensor, and unscrew
sensor from exhaust pipe adapter. Clean adapter threads.
Installation
1) Apply anti-seize compound to sensor threads. Do not allow
compound to adhere to any other part of sensor. Hand start the sensor
into place and tighten. Check that wire terminal ends are properly
seated in connector. Connect wire.
2) Do not push the rubber boot over sensor body lower than
1/2" (13 mm) above base of sensor. If the sensor wire should break,
sensor must be replaced. These wires cannot be spliced or otherwise
repaired.
MANIFOLD AIR TEMPERATURE & MANIFOLD ABSOLUTE PRESSURE SENSORS
Removal & Installation
Disconnect wiring harness connector from sensor. Disconnect
vacuum hose from MAP sensor. Remove sensor. Clean MAT sensor manifold
threads, and wrap with Teflon tape. To install, reverse removal
procedure.
COOLANT TEMPERATURE SENSOR (CTS)
Removal & Installation
Allow engine to cool and release pressure from cooling
system. Remove wiring harness from sensor. Remove sensor at rear of
intake manifold, and plug hole to prevent excessive coolant loss. To
install, reverse removal procedure and replace lost coolant.
EGR VALVE & CANISTER PURGE SOLENOID
Removal & Installation
Disconnect wiring harness and vacuum hose from solenoid.
Remove solenoid and bracket as an assembly. Replace solenoid as an

Terminal loose, not
affecting performance .. 1 .. Suggest repair or replacement.
(1) - Application incorrect includes wrong bulb coating
or color.
( 2) - Determine cause and correct prior to repair or
replacement of part.









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CALIPER HARDWARE
CALIPER HARDWARE INSPECTION








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Condition Code Procedure
Bent ................... A .. Require repair or replacement.
Broken .................. A .. Require repair or replacement.
Corroded, affecting
performance ............ A .. Require repair or replacement.
Dust boots on slider pin
(bolt) missing ......... C ... Require replacement of boots.
Dust boots on slider pin
(bolt) torn ............ A ... Require replacement of boots.
Missing ................. C ............ Require replacement.
Shim bent ............... A ............. ( 1) Require removal
or replacement.
Shim (OE standard)
missing ................ C ........ ( 2) Require replacement.
Shim out of position .... B ............. ( 1) Require removal
or replacement.
Shim worn ............... A ............. ( 1) Require removal
or replacement.
Slider pin (bolt) bent .. B ... Require replacement of slider
pin or bolt and lubricants.
Slider pin (bolt)
rust-pitted ............ A ... Require replacement of slider
pin or bolt and lubricants.
Slider pin (bolt) worn .. A ... Require replacement of slider
pin or bolt and lubricants.
Threads damaged ......... A .. Require repair or replacement.
Threads stripped (threads
missing) ............... A ............ Require replacement.
Worn, affecting
performance ............ A ............ Require replacement.
( 1) - Removal is acceptable if shim is not OE.
( 2) - Aftermarket shims may be suggested to reduce noise.









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CALIPERS
You are not required to replace or rebuild calipers in axle
sets. However, when replacing or rebuilding a caliper due to the
conditions that follow, you may suggest servicing, rebuilding, or
replacement of the other caliper (on the same axle) for improved
performance and preventive maintenance (for example, the part is close
to the end of its useful life, replacing the caliper may extend pad
life, or contribute to more balanced braking).
CAUTION: When installing loaded calipers, it is required that
friction material be matched in axle sets for consistent
braking characteristics.

CALIPER INSPECTION








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Condition Code Procedure
Bleeder port damaged .... A ... Require repair or replacement
of caliper.
Bleeder screw broken off
in caliper ............. A ........... (1) Require repair or
replacement of caliper.
Bleeder screw plugged ... A ........... ( 1) Require repair or
replacement of bleeder screw.
Bleeder screw seized .... A ......... ( 2) Require replacement
of caliper.
Casting corroded,
affecting structural
integrity .............. A ............ Require replacement.
Casting damaged, affecting
structural integrity ... A ............ Require replacement.
Dust boot around caliper
torn ................... A ..... Require replacement of dust
boot.
Leaking ................. A .. Require repair or replacement.
Mounting pin threads
damaged ................ A ... Require repair or replacement
of component with damaged
threads.
Mounting pin threads
stripped in caliper
bracket (threads
missing) ............... A ... Require repair or replacement
of caliper bracket.
Mounting pin threads
stripped in steering
knuckle (threads
missing) ............... A ... Require repair or replacement
of steering knuckle.
Mounting pin threads
stripped (threads
missing) ............... A ... Require repair or replacement
of component with stripped
threads.
Parking brake cable
support, lever, or return
spring bent ............ A ... Require replacement of parts.
Parking brake cable
support, lever, or return
spring broken .......... A ... Require replacement of parts.
Parking brake mechanism in
caliper inoperative .... A .. Require repair or replacement.
Piston corroded (pitted
or peeling chrome
plating) ............... B ... Require replacement of piston
and rebuilding or replacement
of caliper.
Piston damaged, affecting
performance ............ B ... Require replacement of piston
and rebuilding or replacement
of caliper.
Piston damaged, not
affecting performance .. .. ........ No service suggested or
required.
Piston finish worn off .. B ... Require replacement of piston
and rebuilding or replacement

to the conditions that follow, you may suggest rebuilding or
replacement of the other wheel cylinder (on the same axle) for
preventive maintenance, for example, the part is close to the end of
its useful life.
Determine the need to rebuild or replace based upon the
individual wheel cylinder conditions that follow.
WHEEL CYLINDER INSPECTION









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Condition Code Procedure
Attaching hardware bent . B ..... Require replacement of bent
parts.
Attaching hardware
broken ................. A ... Require repair or replacement
of hardware.
Attaching hardware
corroded, affecting
structural integrity ... A . Require replacement of corroded
parts.
Attaching hardware
loose .................. A .. Require repair or replacement.
Attaching hardware
missing ................ C .......... Require replacement of
hardware.
Attaching hardware not
functioning ............ A ... Require repair or replacement
of hardware.
Bleeder port damaged (if
non-repairable) ........ A ............ Require replacement.
Bleeder screw broken off
in wheel cylinder (if non-
repairable) ............ A ........ (1) Require replacement.
Bleeder screw plugged ... A ........... ( 1) Require repair or
replacement of bleeder screw.
Bleeder screw seized .... A ........ ( 2) Require replacement.
Bore corroded (pitted) .. B ............ Require replacement.
Bore grooved ............ A ............ Require replacement.
Bore oversized .......... B ............ Require replacement.
Dust boot missing ....... C ..... Require replacement of dust
boot.
Dust boot torn .......... A . ( 3) Require replacement of dust
boot.
Leaking ................. A ....... ( 4) Require rebuilding or
replacement.
Piston corroded, affecting
performance ............ B ... Require replacement of piston
and rebuilding or replacement
of wheel cylinder.
Piston finish worn off .. B ... Require replacement of piston
and rebuilding or replacement
of wheel cylinder.
Piston stuck in bore .... A .... Require replacement of wheel
cylinder.
Loose ................... B .. Require repair or replacement.
Threads damaged ......... A .. Require repair or replacement.
Threads stripped (threads
missing) ............... A ............ Require replacement.
( 1) - Only required if the hydraulic system must be opened.
( 2) - Seized is defined as bleeder screw that cannot be removed
after a practical attempt at removing. Only required if
the hydraulic system must be opened.

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.

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

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