1988 JEEP CHEROKEE oil pressure

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SU SPEN SIO N - F R O NT

1988 J e ep C hero ke e
1988 FRONT SUSPENSION
Jeep Coil & Leaf Spring
Cherokee, Comanche, Grand Wagoneer, Wagoneer, Wrangler
DESCRIPTION
Cherokee, Comanche and Wagoneer 2WD and 4WD front
suspensions consist of solid axle (tubular axle on 2WD), 4 control
arms, 2 coil springs and track bar. Track bar is used to minimize
front axle side-to-side movement. Stabilizer bar and shock absorbers
control suspension spring movement.
Grand Wagoneer and Wrangler models use leaf spring front
suspension with shock absorbers and stabilizer bar. Wrangler also uses
a track bar to maintain lateral position of front and rear axles.
ADJUSTMENTS
WHEEL ALIGNMENT
See WHEEL ALIGNMENT SPECIFICATIONS & PROCEDURES in WHEEL
ALIGNMENT section.
WHEEL BEARING
NOTE: Bearings should be cleaned, inspected, replaced (if
necessary) and lubricated before adjustment.
CAUTION: Never preload tapered roller bearings or damage to roller
ends will result. Bearings are designed to have a slightly
loose feel when properly adjusted.
2WD Models
1) Raise and support vehicle. Remove wheel and tire
assembly. Remove hub dust cap, cotter pin and nut retainer. Ensure
bearings are thoroughly packed with lithium grease.
2) Rotate hub and rotor assembly by hand, and tighten
retainer nut to 17-25 ft. lbs. (23-34 N.m) to seat bearings.
3) Loosen retainer nut 1/2 turn while rotating hub. Then
retighten nut to 19 INCH lbs. (2 N.m). Install nut retainer and new
cotter pin. Clean hub dust cap and coat inside with clean grease.
Reverse removal procedure for remaining components.
4WD Models (Grand Wagoneer)
1) On models equipped with locking hubs, remove locking
hubs. See appropriate LOCKING HUBS article. On models without locking
hubs, remove hub dust cap and drive gear snap ring. See Fig. 1.
2) Remove drive gear, pressure spring and spring cup. On
all models, remove outer lock nut and lock washer. Tighten inner lock
nut to 50 ft. lbs. (68 N.m) while rotating wheel.
3) Back off inner lock nut 45-65 degrees while rotating
wheel. Install washer and outer lock nut. Tighten outer lock nut to
50 ft. lbs. (68 N.m). Reverse removal procedure to complete
installation.
REMOVAL & INSTALLATION

COIL SPRING
Removal
1) Raise and support vehicle. Remove wheel assembly. Place
reference mark on drive shaft and front axle flange. Disconnect drive
shaft at front axle. Place jack stand under axle housing. Disconnect
lower control arms at axle housing.
2) Disconnect stabilizer bar links and lower shock absorber
mounting bolts at axle housing. Disconnect track bar at the sill
bracket (if equipped). Disconnect center link at pitman arm.
3) Lower axle housing to relieve spring pressure. Remove
spring retainer mounting bolt, then remove retainer and coil spring.
Note component locations for reassembly reference.
NOTE: Coil springs are rated separately for each side of vehicle
depending on optional equipment and type of service. Ensure
springs are marked for installation in original positions.
Installation
1) Install coil spring and spring retainer. Tighten retainer
mounting bolt. Raise axle housing into position. Connect lower
control arms to axle housing.
2) Install lower shock absorber mounting bolts, center
link-to-pitman arm, track bar-to-frame bracket and stabilizer bar
links-to-axle housing. To complete installation, reverse removal
procedure.
LEAF SPRING
Removal & Installation
Raise and support vehicle. Raise axle assembly with jack to
relieve spring tension. On Wrangler models, loosen stabilizer bar
link nut. On all other models, remove stabilizer bar. Remove spring
"U" bolts and plate. Disconnect front and rear shackles from frame.
Lower spring assembly. To install, reverse removal procedure.
UPPER CONTROL ARM &
AXLE HOUSING PIVOT BUSHING
Removal
1) To remove right side upper control arm for 6-cylinder
models, disconnect right side engine mount. Raise and support engine
so rear control arm mounting bolt clears exhaust pipe. On all models,
raise and support vehicle.
2) Remove upper control arm mounting bolt from axle housing.
Disconnect control arm mounting bolt at frame rail. Remove upper
control arm. Repeat procedure for opposite control arm. Inspect
control arm for damage or distortion and replace as needed.
3) Check pivot bushings for excessive distortion,
deterioration or wear. If bushing replacement is necessary, install
Spacer (J-33581-3) between ears of control arm bracket on axle
housing. See Fig. 4.
NOTE: Spacer is not used on axle housings with solid control arm
brackets.
CAUTION: Do not attempt to remove upper control arm pivot bushing
without spacer. Tool is designed to support bracket and
prevent distortion during bushing removal.
4) Install Upper Control Arm Pivot Bushing Remover/Installer
Set (J-35581, which must include Spacer J-35581-3, Remover/Installer

Stud loose in
taper hole ............. A ........... (7) Require repair or
replacement.
Taper hole elongated .... A ........ ( 8) Require replacement.
Threads damaged ......... A .. Require repair or replacement.
Threads stripped (threads
missing) ............... A ........ ( 7) Require replacement.
Wear exceeds
manufacturer's
specifications .......... B ............ Require replacement.
( 1) - If greaseable, grease joint. If problem persists or
joint is non-greaseable, require replacement.
( 2) - Cracked grease boot will allow contaminants to enter
the joint and will accelerate wear.
( 3) - Lack of grease boot will allow contaminants to enter
the joint and will accelerate wear.
( 4) - Torn grease boot will allow contaminants to enter the
joint and will accelerate wear.
( 5) - If manufacturer's procedures for inspection exist, use
those procedures; otherwise, use an approved inspection
method such as the dry park check.
CAUTION: DO NOT use pliers or pry bar to check ball and
socket movement. Use only moderate hand pressure.
( 6) - Excessive looseness is defined as being significant
enough to affect vehicle handling or structural
integrity.
( 7) - Check for damaged taper hole.
( 8) - Check for damaged stud.









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SHOCK ABSORBERS, STRUT CARTRIDGES AND STRUT ASSEMBLIES
You are not required to replace shocks or struts in axle
sets. However, when replacing a shock or strut due to the conditions
that follow, you may suggest replacement of the other shock or strut
on the same axle for improved performance and preventive maintenance.
* Part is close to the end of its useful life
* To extend tire life
* To balance ride and handling
* To improve stopping distance
When replacing steering and/or suspension components which
may affect an alignment angle, you are required to check and adjust
alignment as needed. Refer to the OEM specifications.
Under no circumstances should a technician bend struts or
strut housings.
A vehicle's load-carrying and handling abilities are limited
by its suspension, tires, brakes, and driveline. Installing coil over
shocks or any other load assist device does not increase the vehicle's
load capacity. See the vehicle owner's manual for more details.
NOTE: If vehicle is equipped with original equipment coil over
shocks, apply the conditions for coil springs from the
SPRINGS - COIL, LEAF AND TORSION BAR section of the
STEERING AND SUSPENSION guidelines. If the vehicle is
equipped with add-on coil over shocks, you may suggest
replacing the shocks with standard shocks for any spring-
related condition.
SHOCK ABSORBER, STRUT CARTRIDGE AND STRUT ASSEMBLY INSPECTION









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\003
TR AN SFE R C ASE - N P/N V 2 42

1988 J e ep C hero ke e
1987-96 TRANSFER CASES
Jeep - New Venture 242
Cherokee, Comanche, Wagoneer, Grand Wagoneer
IDENTIFICATION
Transfer case can be identified by an I.D. tag, located on
rear case. I.D. tag provides model number, serial number and low range
ratio. Date of manufacture is the serial number (I.D. number). This
information is necessary when ordering parts.
DESCRIPTION
Model 242 transfer case is a chain-driven, 2-piece aluminum
case, with full time operation. Torque input in 4WD high and low range
is undifferentiated.
ADJUSTMENTS
GEARSHIFT LINKAGE
Remove shift boot and shift to 4L position. Loosen trunnion
nut. Adjust trunnion and shift rod until rod fits freely. Tighten
trunnion nut and remove shim.
TROUBLE SHOOTING
SYMPTOM DIAGNOSIS
Will Not Shift Or Difficult To Shift Into Gear
Check fluid level. Check linkage adjustment. Ensure transfer
case external linkage is not binding. Internal parts may be worn or
damaged.
Noisy In All Gears
Check fluid level. Ensure correct fluid is used. If fluid is
okay, locate noise and check for possible internal mechanical problem.
Jumps Out Of Gear Or Noisy In 4WD
Transfer case not completely in gear; check shift linkage.
Range fork damaged. Inserts are worn. Shift fork binding on shift
rail. Low range gear worn or damaged.
Fluid Leaking From Vent Or Seals
Transfer case overfilled. Vent plugged. Output shaft seals
are damaged or not installed properly.
Transfer Case Will Not Shift Through High Lock Range
Incomplete shift due to driveline torque load; momentarily
release accelerator pedal to complete shift. Check tire pressure and
tire wear. Vehicle overloaded; remove load and check shifting.
ON-VEHICLE SERVICE
FRONT OIL SEAL

Fires With Key Flywheel runout contributes
released. Engine to the intermittent nature
Fires and Cranks
Normally









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AIR CONDITIONING & HEAT
AIR CONDITIONING TROUBLE SHOOTING
WARNING: This is GENERAL information. This article is not intended
to be specific to any unique situation or individual vehicle
configuration. The purpose of this Trouble Shooting
information is to provide a list of common causes to
problem symptoms. For model-specific Trouble Shooting,
refer to SUBJECT, DIAGNOSTIC, or TESTING articles available
in the section(s) you are accessing.
BASIC AIR CONDITIONING TROUBLE SHOOTING CHART









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CONDITION POSSIBLE CAUSE








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Compressor Not Working
Compressor clutch circuit open.

Compressor clutch coil inoperative.

Poor clutch ground connection.

Fan belts loose.

Thermostatic switch inoperative.

Thermostatic switch not adjusted.

Ambient temperature switch open.

Superheat fuse blown.








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Excessive Noise or Vibration
Missing or loose mounting bolts.

Bad idler pulley bearings.

Fan belts not tightened correctly.

Compressor clutch contacting body.

Excessive system pressure.

Compressor oil level low.

Damaged clutch bearings.

Damaged reed valves.

Damaged compressor.








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Insufficient or No Cooling;
Compressor Working
Expansion valve inoperative.

Heater control valve stuck open.

Low system pressure.

Blocked condenser fins.

Blocked evaporator fins.

Vacuum system leak.

Vacuum motors inoperative.

Control cables improperly adjusted.

Restricted air inlet.

Mode doors binding.

Blower motor inoperative.

Temperature above system capacity.








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HEATER SYSTEM TROUBLE SHOOTING
NOTE: This is GENERAL information. This article is not intended
to be specific to any unique situation or individual vehicle
configuration. The purpose of this Trouble Shooting
information is to provide a list of common causes to

BRAKE SYSTEM TROUBLE SHOOTING CHART








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CONDITION POSSIBLE CAUSE CORRECTION








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Brakes Pull Left
or Right Incorrect tire pressure Inflate tires to proper
pressure
Front end out of alignment See WHEEL ALIGNMENT
Mismatched tires Check tires sizes
Restricted brake lines
or hoses Check hose routing
Loose or malfunctioning
caliper See DISC BRAKES or
BRAKE SYSTEM
Bent shoe or oily linings See DRUM BRAKES or
BRAKE SYSTEM
Malfunctioning rear brakes See DRUM, DISC BRAKES
or BRAKE SYSTEM
Loose suspension parts See SUSPENSION









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Noises Without
Brakes Applied Front linings worn out Replace linings
Dust or oil on drums See DRUM, DISC BRAKES
or rotors or BRAKE SYSTEM









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Noises With
Brakes Applied Insulator on outboard See DISC BRAKES or
shoe damaged BRAKE SYSTEM
Incorrect pads or linings Replace pads or linings









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Brake Rough, Chatters
or Pulsates Excessive lateral runout Check rotor runout
Parallelism not to
specifications Reface or replace rotor
Wheel bearings not adjusted See SUSPENSION
Rear drums out-of-round Reface or replace drums
Disc pad reversed, steel
against rotor Remove and reinstall
pad









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Excessive Pedal
Effort Malfunctioning power unit See POWER BRAKES or
BRAKE SYSTEM
Partial system failure Check fluid and pipes
Worn disc pad or lining Replace pad or lining
Caliper piston stuck or

Incorrect ignition timing Reset ignition timing,
See TUNE-UP
Leaking valves Replace valves, See
ENGINES
Worn fuel pump diaphragm Replace diaphragm or
or piston piston









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Intake Backfire Improper ignition timing Reset ignition timing,
See TUNE-UP
Faulty accelerator pump Replace accelerator
discharge pump
Improper choke operation Check choke and adjust
as required
Defective EGR valve Replace EGR valve
Fuel mixture too lean Reset air/fuel mixture,
See TUNE-UP
Choke valve initial Reset choke valve
clearance too large initial clearance









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Exhaust Backfire Vacuum leak Inspect and repair
vacuum system
Faulty vacuum diverter Replace vacuum diverter
valve valve
Faulty choke operation Check choke and adjust
as required
Exhaust system leak repair exhaust system
leak









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Engine Ignition timing too far Reset ignition timing,
Detonation advanced See TUNE-UP
Faulty ignition system Check ignition timing,
See TUNE-UP
Spark plugs loose or Retighten or replace
faulty plugs
Fuel delivery system Inspect lines, pump and
clogged filter for clog
EGR valve inoperative Replace EGR valve
PCV system inoperative Inspect and/or replace
hoses or valve
Vacuum leaks Check vacuum system and
repair leaks
Excessive combustion
chamber deposits Remove built-up
deposits
Leaking, sticking or Inspect and/or replace
broken valves valves









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External Oil Fuel pump improperly seated Remove pump, replace
Leakage or worn gasket gasket and seat
properly
Oil pan gasket broken or Straighten pan and
pan bent replace gasket
Timing chain cover gasket Replace timing chain
broken cover gasket
Rear main oil seal worn Replace rear main oil
seal
Oil pan drain plug not Remove and reinstall
seated properly drain plug
Camshaft bearing drain Remove restriction
hole blocked
Oil pressure sending Remove and reinstall
switch leaking sending switch









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Excessive Oil Worn valve stems or guides Replace stems or
Consumption guides, See ENGINES
Valve "O" ring seals Replace "O" ring seals,
damaged See ENGINES
Plugged oil drain back holes Remove restrictions
Improper PCV valve Replace PCV valve
operation
Engine oil level too high Remove excess oil
Engine oil too thin Replace thicker oil
Valve stem oil deflectors Replace oil deflectors
damaged
Incorrect piston rings Replace piston rings,
See ENGINES
Piston ring gaps not Reinstall piston rings,
staggered See ENGINES
Insufficient piston ring Replace rings, See
tension ENGINES
Piston ring grooves or oil Replace piston rings,
return slots clogged See ENGINES
Piston rings sticking in Replace piston rings,
grooves See ENGINES
Piston ring grooves Replace piston and
excessively worn rings, See ENGINES
Compression rings installed Replace compression
upside down rings correctly, See
ENGINES
Worn or scored cylinder Rebore cylinders or
walls replace block
Mismatched oil ring Replace oil ring
expander and rail expander and rail, See
ENGINES
Intake gasket dowels too Replace intake gasket
long dowels
Excessive main or connecting Replace main or
rod bearing clearance connecting rod
bearings, See ENGINES









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No Oil Pressure Low oil level Add oil to proper level
Oil pressure sender or Replace sender or gauge
gauge broken
Oil pump malfunction Remove and overhaul oil
pump, See ENGINES
Oil pressure relief valve Remove and reinstall
sticking valve
Oil pump passages blocked Overhaul oil pump, See
ENGINES
Oil pickup screen or tube remove restriction
blocked
Loose oil inlet tube Tighten oil inlet tube
Loose camshaft bearings Replace camshaft
bearings, See ENGINES
Internal leakage at oil Replace block or
passages cylinder head









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Low Oil Pressure Low engine oil level Add oil to proper level
Engine oil too thin Remove and replace with
thicker oil
Excessive oil pump Reduce oil pump
clearance clearance, See ENGINES
Oil pickup tube or screen Remove restrictions
blocked
Main, rod or cam bearing Replace bearing to
clearance excessive reduce clearance, See