1995 JEEP YJ air suspension

GROUP TAB LOCATOR
Introduction
0Lubrication and Maintenance
2Front Suspension and Axle
3Rear Suspension and Axles
5Brakes
6Clutch
7Cooling System
8Electrical
9Engines
11Exhaust System and Intake Manifold
13Frame and Bumpers
14Fuel System
16Propeller Shafts
19Steering
21Transmission and Transfer Cases
22Wheels and Tires
23Body Components
24Heating and Air Conditioning
25Emission Control Systems
Index
Service Manual Comment Forms (Rear of Manual)

CLASSIFICATION OF LUBRICANTS
Lubricating fluids and chassis lubricants are clas-
sified according to standards recommended by the:
²Society of Automotive Engineers (SAE)
²American Petroleum Institute (API)
²National Lubricating Grease Institute (NLGI)
ENGINE OIL
API CERTIFICATION MARK
For maximum engine protection during all driving
conditions, install an engine oil that contains the API
Certification Mark (Fig. 2). The API Certification
Mark indicates that the oil is certified to meet the
most critical requirements established by the manu-
facturer.
Conformance to API specifications is determined by
tests that measure the ability of an oil to control:
²Engine wear.
²Bearing corrosion.
²Sludge.
²Varnish.
²Oil thickening.
²Rust.
²Piston deposits.
SAE VISCOSITY GRADE
An SAE viscosity grade is used to specify the vis-
cosity of engine oil. SAE 30 specifies a single viscos-
ity engine oil. Engine oils also have multiple
viscosities. These are specified with a dual SAE vis-
cosity grade which indicates the cold-to-hot tempera-
ture viscosity range.
API SERVICE GRADE CERTIFIED
The API Service Grade specifies the type of perfor-
mance the engine oil is intended to provide. The API
Service Grade specifications also apply to energy con-
serving engine oils.
Use an engine oil that is API Service Grade Certi-
fied or an oil that conforms to the API Service Grade
SH or SH/CD. MOPAR provides engine oils that con-
form to all of these service grades.
GEAR LUBRICANTS
A dual grade is also used to specify the viscosity of
multi-purpose gear lubricants.
The API grade designation identifies gear lubri-
cants in terms of recommended usage.
CHASSIS COMPONENT AND WHEEL BEARING
LUBRICANTS
The chassis and wheel bearing lubricants that are
recommended are identified by the NLGI Certifica-
tion Symbol. The symbol contains a coded designa-
tion. This identifies the usage and quality of the
lubricant.
The letter G within the symbol designates wheel
bearing lubricant. The letter L designates chassis lu-
bricant. When the letters are combined, the lubricant
can be used for dual applications. Use only lubricants
that display the NLGI Certification Symbol (Fig. 3).
LUBRICATION AND REPLACEMENT PARTS
RECOMMENDATION
Jeep vehicles are engineered to provide many years
of dependable operation. However, lubrication service
and maintenance are required for each vehicle. When
necessary, MOPARtbrand lubricants and genuine re-
placement parts are highly recommended. Each MO-
PAR brand lubricant and replacement part is
designed and to provide dependability and long ser-
vice life.
COMPONENTS REQUIRING NO LUBRICATION
There are many components that should not be lu-
bricated. The components that should not be lubri-
cated are:
²Air pumps.
²Generator bearings.
²Distributors.
²Drive belts.
²Drive belt idler pulleys.
²Rubber bushings.
²Starter motor bearings.
²Suspension strut bearings.
²Throttle control cables.
²Throttle linkage ball joints.
²Water pump bearings.
Fig. 2 The API Engine Oil Certification Mark
Fig. 3 NLGI Lubricant Container Certification/
Identification Symbol
0 - 2 LUBRICATION AND MAINTENANCEJ

even tire wear. The wheel toe position is thefinal
front wheel alignment adjustment.
²STEERING AXIS INCLINATION ANGLE is mea-
sured in degrees and is the angle that the steering
knuckles are tilted (Fig. 1). The inclination angle has
a fixed relationship with the camber angle. It will not
change except when a spindle or ball stud is dam-
aged or bent. The angle is not adjustable, the dam-
aged component(s) must be replaced to correct mis-
alignment.
WARNING: DO NOT ATTEMPT TO MODIFY ANY
SUSPENSION OR STEERING COMPONENT BY
HEATING AND BENDING.
PRE-ALIGNMENT INSPECTION
Before starting a front wheel alignment, the follow-
ing inspection and necessary corrections must be
completed.(1) Tires with the same recommended air pressure,
size, and thread wear. Refer to Group 22, Tires And
Wheels for diagnosis information.
(2) Front wheel bearings for wear and looseness.
(3) Ball studs, steering linkage pivot points and
steering gear for looseness, roughness, binding or
wear. Refer to Group 19, Steering for additional in-
formation.
(4) Front wheels for excessive radial or lateral
runout and unbalance. Refer to Group 22, Tires And
Wheels for diagnosis information.
(5) Suspension components for wear. Check compo-
nents for correct torque. Refer to Groups 2 and 3,
Suspension and Axle for additional information.
2 - 6 FRONT SUSPENSION AND AXLEJ

LOWER SUSPENSION ARM
REMOVAL
(1) Raise and support the vehicle.
(2) Remove the lower suspension arm nut and bolt
from the axle bracket (Fig. 3).
(3) Remove the nut and bolt (Fig. 3) from the rear
bracket and remove the lower suspension arm.
INSTALLATION
(1) Position the lower suspension arm at the axle
bracket and rear bracket (Fig. 3).
(2) Install the bolts and finger tighten the nuts
(Fig. 3).
(3) Remove support and lower the vehicle.
(4) Tighten the front and rear nuts to 115 Nzm (85
ft. lbs.) torque.
SPRING AND SHOCK DIAGNOSIS
A squeak noise from the shock absorber can be pro-
duced if movement between the rubber bushings and
the metal occurs. This noise can usually be stopped
by tightening the attaching nuts. If the squeak noise
persists, inspect for damaged and worn bushings,
and attaching components. Repair as necessary.
The shock absorber bushings do not require any
type of lubrication. Do not lubricate the bushings to
reduce bushing noise. Grease or mineral oil-base lu-
bricants will deteriorate the bushing rubber.
The shock absorbers are not refillable or adjust-
able. If a malfunction occurs, the shock absorber
must be replaced. To test a shock absorber, hold it in
an upright position and force the piston into and out
of the cylinder four or five times. The action through-
out each stroke should be smooth and even.
SHOCK ABSORBER
REMOVAL
(1) Remove the nut, retainer and grommet from
the upper stud in the engine compartment (Fig. 6).
(2) Remove the lower nuts and bolts from the axle
bracket (Fig. 6). Remove the shock absorber.
Fig. 6 Coil Spring & Shock Absorber
Fig. 5 Axle Bracket Bushing Installation
JFRONT SUSPENSION AND AXLE 2 - 13

YJ FRONT SUSPENSION
INDEX
page page
Leaf Spring.............................. 16
Leaf Spring Eye Bushing Replacement......... 17
Service Information........................ 15
Shock Absorber.......................... 16Spring and Shock Diagnosis................. 15
Stabilizer Bar............................ 15
Track Bar............................... 15
SERVICE INFORMATION
Periodic lubrication of the steering system and sus-
pension components is required. Refer to Group 0,
Lubrication And Maintenance for the service inter-
val.
CAUTION: Suspension components with rubber
bushings should be tightened with the vehicle at
normal height. It is important to have the springs
supporting the weight of the vehicle when the fas-
teners are torqued. If springs are not at their normal
ride position, vehicle ride comfort could be affected
and premature bushing wear may occur. Rubber
bushings must never be lubricated.
TRACK BAR
REMOVAL
(1) Raise and support the vehicle.
(2) Remove the retaining nuts and bolts (Fig. 1)
from the axle bracket and frame bracket. Remove
track bar.
INSTALLATION
(1) Position track bar at axle shaft tube bracket.
Loosely install the retaining bolt and nut (Fig. 1).
(2) Loosely install the retaining bolt and nut at the
frame bracket.
(3) Remove support and lower vehicle.
(4) Tighten the retaining nut at the axle shaft tube
bracket to 100 Nzm (74 ft. lbs.) torque.
(5) Tighten the retaining nut at the frame bracket
to 142 Nzm (105 ft. lbs.) torque.
STABILIZER BAR
REMOVAL
(1) Raise and support the vehicle.
(2) Remove the retaining nut from the connecting
link bolt (Fig. 2).
(3) Remove the retaining clamps from frame rails
(4) Remove the stabilizer bar.
INSTALLATION
(1) Inspect the stabilizer bar bushings (Fig. 2). Re-
place the bushings if cracked, cut, distorted, or worn.(2) Position the stabilizer bar on the frame. Install
the retaining brackets and fasteners. Tighten bolts to
41 Nzm (30 ft. lbs.) torque.
(3) Install the link upper bolts and nuts. Tighten
the nuts to 61 Nzm (45 ft. lbs.) torque.
(4) Tighten the link spring bracket nuts to 61 Nzm
(45 ft. lbs.) torque.
(5) Lower the vehicle.
SPRING AND SHOCK DIAGNOSIS
A squeak noise from the shock absorber or springs
can be produced if movement between the rubber
bushings and the metal occurs. This noise can usu-
ally be stopped by tightening the attaching nuts. If
the squeak noise persists, inspect for damaged and
worn bushings, and attaching components. Repair as
necessary if any of these conditions exist.
Fig. 1 Track Bar
JFRONT SUSPENSION AND AXLE 2 - 15

AXLE NOISE/VIBRATION DIAGNOSIS
INDEX
page page
Driveline Snap........................... 19
Gear and Bearing Noise.................... 18
General Information....................... 18Low Speed Knock......................... 19
Vibration................................ 19
GENERAL INFORMATION
Axle bearing problem conditions are usually caused
by:
²Insufficient or incorrect lubricant
²Foreign matter/water contamination
²Incorrect bearing preload torque adjustment
²Incorrect backlash (to tight)
When serviced, the bearings must be cleaned thor-
oughly. They should be dried with lint-free shop tow-
els.Never dry bearings with compressed air.
This will overheat them and brinell the bearing
surfaces. This will result in noisy operation af-
ter repair.
Axle gear problem conditions are usually the result
of:
²Insufficient lubrication
²Incorrect or contaminated lubricant
²Overloading (excessive engine torque) or exceeding
vehicle weight capacity
²Incorrect clearance or backlash adjustment
Insufficient lubrication is usually the result of a
housing cover leak. It can also be from worn axle
shaft or pinion gear seals. Check for cracks or porous
areas in the housing or tubes.
Using the wrong lubricant will cause overheating
and gear failure. Gear tooth cracking and bearing
spalling are indicators of this.
Axle component breakage is most often the result
of:
²Severe overloading
²Insufficient lubricant
²Incorrect lubricant
²Improperly tightened components
Overloading occurs when towing heavier than rec-
ommended loads. Component breakage can occur
when the wheels are spun excessively. Incorrect lu-
bricant quantity contributes to breakage. Loose dif-
ferential components can also cause breakage.
Incorrect bearing preload or gear backlash will not
result in component breakage. Mis-adjustment will
produce enough noise to cause service repair before a
failure occurs. If a mis-adjustment condition is not
corrected, component failure can result.
Excessive bearing preload may not be noisy. This
condition will cause high temperature which can re-
sult in bearing failure.
GEAR AND BEARING NOISE
GEAR NOISE
Axle gear noise can be caused by insufficient lubri-
cant. Incorrect backlash, tooth contact, or worn/dam-
aged gears can cause noise.
Gear noise usually happens at a specific speed
range. The range is 30 to 40 mph, or above 50 mph.
The noise can also occur during a specific type of
driving condition. These conditions are acceleration,
deceleration, coast, or constant load.
When road testing, accelerate the vehicle to the
speed range where the noise is the greatest. Shift
out-of-gear and coast through the peak-noise range.
If the noise stops or changes greatly, check for insuf-
ficient lubricant. Incorrect ring gear backlash, or
gear damage can cause noise changes.
Differential side and pinion gears can be checked
by turning the vehicle. They usually do not cause
noise in straight-ahead driving. These gears are
loaded during vehicle turns. If noise does occur dur-
ing vehicle turns, the side or pinion gears could be
worn or damaged. A worn pinion gear mate shaft can
also cause a snapping or a knocking noise.
BEARING NOISE
The axle shaft, differential and pinion gear bear-
ings can all produce noise when worn or damaged.
Bearing noise can be either a whining, or a growling
sound.
Pinion gear bearings have a constant-pitch noise.
This noise changes only with vehicle speed. Pinion
bearing noise will be higher because it rotates at a
faster rate. Drive the vehicle and load the differen-
tial. If bearing noise occurs the pinion rear bearing is
the source of the noise. If the bearing noise is heard
during a coast, front bearing is the source.
Worn, damaged differential bearings usually pro-
duce a low pitch noise. Differential bearing noise is
similar to pinion bearing. The pitch of differential
bearing noise is also constant and varies only with
vehicle speed.
2 - 18 FRONT SUSPENSION AND AXLEJ

Axle shaft bearings produce noise and vibration
when worn or damaged. The noise generally changes
when the bearings are loaded. Road test the vehicle.
Turn the vehicle sharply to the left and to the right.
This will load the bearings and change the noise
level. Where axle bearing damage is slight, the noise
is usually not noticeable at speeds above 30 mph.
LOW SPEED KNOCK
Low speed knock is generally caused by a worn U-
joint or by worn side-gear thrust washers. A worn
pinion gear shaft bore will also cause low speed
knock.
VIBRATION
Vibration at the rear of the vehicle is usually
caused by a:
²Damaged drive shaft
²Missing drive shaft balance weight
²Worn, out-of-balance wheels
²Loose wheel lug nuts
²Worn U-joint
²Loose spring U-bolts
²Loose/broken springs
²Damaged axle shaft bearings
²Loose pinion gear nut
²Excessive pinion yoke run out²Bent axle shaft
Check for loose or damaged front-end components
or engine/transmission mounts. These components
can contribute to what appears to be a rear-end vi-
bration. Do not overlook engine accessories, brackets
and drive belts.
All driveline components should be examined be-
fore starting any repair.
Refer to Group 22ÐTires And Wheels for addi-
tional information involving vibration diagnosis.
DRIVELINE SNAP
A snap or clunk noise when the vehicle is shifted
into gear (or the clutch engaged), can be caused by:
²High engine idle speed
²Loose engine/transmission/transfer case mounts
²Worn U-joints
²Loose spring mounts
²Loose pinion gear nut and yoke
²Excessive ring gear backlash
²Excessive differential side gear-to-case clearance
The source of a snap or a clunk noise can be deter-
mined with the assistance of a helper. Raise the ve-
hicle on a hoist with the wheels free to rotate.
Instruct the helper to shift the transmission into
gear. Listen for the noise, a mechanics stethoscope is
helpful in isolating the source of a noise.
JFRONT SUSPENSION AND AXLE 2 - 19

(6) Remove the remaining bearing cap, bearings,
seals and spider from the propeller shaft yoke.
CLEANING AND INSPECTION
(1) Clean all the U-joint yoke bores with cleaning
solvent and a wire brush. Ensure that all the rust
and foreign matter are removed from the bores.
(2) Inspect the yokes for distortion, cracks and
worn bearing cap bores.
(3) Replace the complete U-joint if any of the com-
ponents are defective.
ASSEMBLY
(1) Pack the bearing caps 1/3 full of wheel bearing
lubricant. Apply extreme pressure (EP), lithium-base
lubricant to aid in installation.
(2) Position the spider in the yoke. Insert the seals
and bearings. Tap the bearing caps into the yoke
bores far enough to hold the spider in position.
(3) Place the socket (driver) against one bearing
cap. Position the yoke with the socket wrench in a
vise.
(4) Compress the vise to force the bearing caps into
the yoke. Force the caps enough to install the retain-
ing clips.
(5) Install the bearing cap retaining clips.
(6) Install the axle shaft, refer to Hub Bearing and
Axle Shaft installation.
VACUUM DISCONNECT AXLEÐYJ VEHICLES
VACUUM CONTROL SYSTEM
The disconnect axle control system consists of;
²Vacuum control switch on the transfer case
²Air vent filter
²Shift motor
²Indicator switch
²Vacuum switch
²Check valve
²Vacuum harness (Fig. 9, 10)
Refer to Group 21ÐTransmissions for addi-
tional information involving the Command-Trac
System Transfer Case.
Fig. 8 Yoke Bearing Cap Removal
Fig. 9 Vacuum Control System
JFRONT SUSPENSION AND AXLE 2 - 27