1995 JEEP XJ tires

produce a condition similar to grab as the tire loses
and recovers traction.
Flat-spotted tires can cause vibration and wheel
tramp and generate shudder during brake operation.
A tire with internal damage such as a severe bruise
or ply separation can cause vibration and pull. The
pull will be magnified when braking.
DIAGNOSING PARKING BRAKE MALFUNCTIONS
Adjustment Mechanism
Parking brake adjustment is controlled by a ca-
ble tensioner mechanism. The cable tensioner,
once adjusted at the factory, will not need further
attention under normal circumstances. There are
only two instances when adjustment is required.
The first is when a new tensioner, or cables have
been installed. And the second, is when the ten-
sioner and cables are disconnected for access to
other brake components.
Parking Brake Switch And Warning Light Illumination
The parking brake switch on the lever, or foot
pedal, is in circuit with the red warning light. The
switch will illuminate the red light only when the
parking brakes are applied. If the light remains on
after parking brake release, the switch or wires are
faulty, or cable tensioner adjustment is incorrect.
If the red light comes on while the vehicle is in mo-
tion and brake pedal height decreases, a fault has oc-
curred in the front or rear brake hydraulic system.
Parking Brake problem Causes
In most cases, the actual cause of an improperly
functioning parking brake (too loose/too tight/wont
hold), can be traced to a drum brake component.
The leading cause of improper parking brake
operation, is excessive clearance between the
brakeshoes and the drum surface. Excessive
clearance is a result of: lining and/or drum
wear; oversize drums; or inoperative shoe ad-
juster components.
Excessive parking brake lever travel (sometimes de-
scribed as a loose lever or too loose condition), is the re-
sult of worn brakeshoes/drums, improper brakeshoe
adjustment, or incorrectly assembled brake parts.
A ``too loose'' condition can also be caused by inop-
erative brakeshoe adjusters. If the adjusters are mis-
assembled, they will not function. In addition, since
the adjuster mechanism only works during reverse
stops, it is important that complete stops be made.
The adjuster mechanism does not operate when roll-
ing stops are made in reverse. The vehicle must be
brought to a complete halt before the adjuster lever
will turn the adjuster screw.
A condition where the parking brakes do not hold, will
most probably be due to a wheel brake component.
Items to look for when diagnosing a parking brake
problem, are:
²rear brakeshoe wear or adjuster problem
²rear brake drum wear
²brake drums machined beyond allowable diameter
(oversize)
²parking brake front cable not secured to lever
²parking brake rear cable seized
²parking brake strut reversed
²parking brake strut not seated in both shoes
²parking brake lever not seated in secondary shoe
²parking brake lever or brakeshoe bind on support
plate
²brakeshoes reversed
²adjuster screws seized
²adjuster screws reversed
²holddown or return springs misassembled or lack
tension
²wheel cylinder pistons seized
Brake drums that are machined oversize are diffi-
cult to identify without inspection. If oversize drums
are suspected, diameter of the braking surface will
have to be checked with an accurate drum gauge.
Oversize drums will cause low brake pedal and lack
of parking brake holding ability.
Improper parking brake strut and lever installation
will result in unsatisfactory parking brake operation.
Intermixing the adjuster screws will cause drag, bind
and pull along with poor parking brake operation.
Parking brake adjustment and parts replacement pro-
cedures are described in the Parking Brake section.
MASTER CYLINDER/POWER BOOSTER TEST
(1) Start engine and check booster vacuum hose
connections. Hissing noise indicates vacuum leak.
Correct any vacuum leak before proceeding.
(2) Stop engine and shift transmission into Neu-
tral.
(3) Pump brake pedal until all vacuum reserve in
booster is depleted.
(4) Press and hold brake pedal under light foot
pressure.
(a) If pedal holds firm, proceed to step (5).
(b) If pedal does not hold firm and falls away,
master cylinder is faulty due to internal leakage.
Overhaul or replace cylinder.
(5) Start engine and note pedal action.
(a) If pedal falls away slightly under light foot
pressure then holds firm, proceed to step (6).
(b) If no pedal action is discernible, or hard pedal
is noted, power booster or vacuum check valve is
faulty. Install known good check valve and repeat
steps (2) through (5).
(6) Rebuild booster vacuum reserve as follows: Re-
lease brake pedal. Increase engine speed to 1500
rpm, close throttle and immediately turn off ignition.
5 - 8 SERVICE BRAKE DIAGNOSISJ

SERVICE DIAGNOSIS
INDEX
page page
Runout.................................. 4
Unbalance............................... 3Universal Joint Angle Measurement............. 4
Vibration................................. 3
VIBRATION
Tires that are out-of-round or wheels that are un-
balanced will cause a low frequency vibration. Refer
to Group 22, Wheels and Tires for additional infor-
mation.
Brake drums that are unbalanced will cause a
harsh, low frequency vibration. Refer to Group 5,
Brakes for additional information.
Driveline vibration can also result from loose or
damaged engine mounts. Refer to Group 21, Trans-
missions for additional information.
Propeller shaft vibration will increase as the vehi-
cle speed is increased. A vibration that occurs within
a specific speed range is not caused by propeller
shaft unbalance. Defective universal joints or an in-
correct propeller shaft angle are usually the cause.
UNBALANCE
If propeller shaft unbalance is suspected, it can be
verified with the following procedure.
Removing and re-indexing the propeller shaft
180É may eliminate some vibrations.
²Clean all the foreign material from the propeller
shaft and the universal joints.²Inspect the propeller shaft for missing balance
weights, broken welds, and bent areas.If the pro-
peller shaft is bent, it must be replaced.
²Ensure the universal joints are not worn, are prop-
erly installed, and are correctly aligned with the
shaft.
²Check the universal joint clamp screws torque
(1) Raise the vehicle.
(2) Remove the wheel and tires assembly. Install
the wheel lug nuts to retain the brake drums.
(3) Mark and number the shaft six inches from the
yoke end at four positions 90É apart.
(4) Run and accelerate the vehicle until vibration
occurs. Note the intensity and speed the vibration oc-
curred. Stop the engine.
(5) Install a screw clamp at position 1 (Fig. 1).
(6) Start the engine and re-check for vibration. If
there is little or no change in vibration, move the
clamp to one of the other three positions. Repeat the
vibration test.
(7) If there is no difference in vibration at the
other positions, the vibration may not be propshaft
unbalance.
DRIVELINE VIBRATION
JPROPELLER SHAFTS 16 - 3

(8) If the vibration decreased, install a second
clamp (Fig. 2) and repeat the test.
(9) If the clamps cause an additional unbalance,
separate the clamps (1/4 inch above and below the
mark). Repeat the vibration test (Fig. 3).(10) Increase distance between the clamp screws
and repeat the test until the amount of vibration is
at the lowest level. Bend the slack end of the clamps
so the screws will not loosen.
(11) Install the wheel and tires. Lower the vehicle.
(12) If the amount of vibration remains unaccept-
able, apply procedures at the front end of the propel-
ler shaft.
RUNOUT
(1) Remove dirt, rust, paint, and undercoating
from the propeller shaft surface. Areas where the dial
indicator will contact the shaft must be clean.
(2) The dial indicator must be installed perpendic-
ular to the shaft surface.
(3) Measure runout at the center and ends away
from welds.
(4) Refer to Runout Specifications chart.
(5) Replace the propeller shaft if the runout ex-
ceeds the limit.
UNIVERSAL JOINT ANGLE MEASUREMENT
INFORMATION
When two shafts come together at any common
joint, the bend that is formed is called the operating
angle. The larger the angle, the larger the amount of
acceleration and deceleration of the joint. This speed-
ing up and slowing down of the joint must be can-
celled to produce a smooth power flow. This is done
through phasing and proper universal joint working
angles.
A propeller shaft is properly phased when the yoke
ends are on the same plane or in line. A twisted shaft
will throw the yokes out of phase and cause a notice-
able vibration.
When taking universal joint angle measurements
or checking phasing with two piece shafts, consider
each shaft separately. On 4WD vehicles, the front
shaft input (pinion shaft) angle has priority over the
caster angle.
Ideally the driveline system should have;
²Angles that are in equal or opposite within 1 de-
gree of each other
²Have a 3 degree maximum operating angle
Fig. 1 Clamp Screw At Position 1
Fig. 2 Two Clamp Screws At The Same Position
Fig. 3 Clamp Screws Separated
RUNOUT SPECIFICATIONS
16 - 4 PROPELLER SHAFTSJ

²Have at least a 1/2 degree continuous operating
(propeller shaft) angle
Engine speed (R.P.M.) is the main factor though in
determining maximum allowable operating angles.
As a guide to maximum normal operating angles re-
fer to the chart listed (Fig. 4).
INSPECTION
Before measuring universal joint angles, the
following must be done.
²Inflate all tires to correct pressure
²Check angles in the same loaded or unloaded con-
dition as when the vibration occurred. Propshaft an-
gles will change according to the amount of load in
the vehicle. Always check angles in loaded and un-
loaded conditions.
²Check the condition of all suspension components
and verify all fasteners are torqued to specifications.
²Check the condition of the engine and transmis-
sion mounts and verify all fasteners are torqued to
specifications.
MEASUREMENT
To accurately check driveline alignment, raise and
support the vehicle at the axles as level as possible.
Allow the wheels and propeller shaft to turn. Remove
any external bearing snap rings (if equipped) from
universal joint so protractor base sits flat.
(1) Rotate the shaft until transmission/transfer
case output yoke bearing is facing downward.
Always make measurements from front to
rear.
(2) Place Inclinometer on yoke bearing (A) parallel
to the shaft (Fig. 5). Center bubble in sight glass and
record measurement.
This measurement will give you the transmis-
sion or OUTPUT YOKE ANGLE (A).
(3) Rotate propeller shaft 90 degrees and place In-
clinometer on yoke bearing parallel to the shaft (Fig.
6). Center bubble in sight glass and record measure-
ment. This measurement can also be taken at the
rear end of the shaft.
This measurement will give you the PROPEL-
LER SHAFT ANGLE (C).(4) Subtract smaller figure from larger (C minus A)
to obtain transmission OUTPUT OPERATING AN-
GLE.
(5) Rotate propeller shaft 90 degrees and place In-
clinometer on pinion yoke bearing parallel to the
shaft (Fig. 7). Center bubble in sight glass and record
measurement.
This measurement will give you the pinion
shaft or INPUT YOKE ANGLE (B).
(6) Subtract smaller figure from larger (C minus
B) to obtain axle INPUT OPERATING ANGLE.
Refer to rules given below and the example in (Fig.
8) for additional information.
Fig. 4 Maximum Angles and R.P.M.
Fig. 5 Front (Output) Angle Measurement (A)
Fig. 6 Propeller Shaft Angle Measurement (C)
JPROPELLER SHAFTS 16 - 5

WHEELS AND TIRES
CONTENTS
page page
SPECIFICATIONS........................ 12
TIRES.................................. 1VEHICLE VIBRATION..................... 10
WHEELS................................ 6
TIRES
INDEX
page page
Cleaning of Tires.......................... 2
General Information........................ 1
Pressure Gauges.......................... 2
Repairing Leaks........................... 3
Replacement Tires......................... 2Rotation................................. 3
Tire Inflation Pressures...................... 2
Tire Noise or Vibration...................... 4
Tire Wear Patterns......................... 4
Tread Wear Indicators....................... 3
GENERAL INFORMATION
Tires are designed for each specific vehicle. They
provide the best overall performance for normal oper-
ation. The ride and handling characteristics match
the vehicle's requirements. With proper care they
will give excellent reliability, traction, skid resis-
tance, and tread life. These tires have specific load
carrying capacities. When correctly inflated, they will
operate properly.
Tires used in cool climates, and with light loads
will have a longer life than tires used in hot climates
with heavy loads. Abrasive road surfaces will acceler-
ate tire wear.
Driving habits have more effect on tire life than
any other factor. Careful drivers will obtain much
greater mileage than careless drivers.
Driving habits that shorten the life of any tire;
²Rapid acceleration and deceleration
²Severe application of brakes
²High-speed driving
²Taking turns at excessive speeds
²Striking curbs and other obstacles
It is very important to follow the tire rotation in-
terval
IDENTIFICATION
Tire type, size, aspect ratio and speed rating are
encoded in the letters and numbers imprinted on the
side wall of the tire. Refer to the chart to decipher
the tire identification code (Fig. 1).Performance tires will have a speed rating letter
after the aspect ratio number. The speed rating is not
always printed on the tire sidewall. The letterSin-
dicates that the tire is speed rated up to 112 mph.
²Qup to 100 mph
²Tup to 118 mph
²Uup to 124 mph
²Hup to 130 mph
²Vup to 149 mph
²Zmore than 149 mph (consult the tire manufac-
turer for the specific speed rating)
An All Season type tire will have eitherM+S,M
&SorMÐS(indicating mud and snow traction) im-
printed on the side wall.
RADIAL-PLY TIRES
Radial-ply tires improve handling, tread life, ride
quality and decrease rolling resistance.
Radial-ply tires must always be used in sets of
four. Under no circumstances should they be used on
the front only. They may be mixed with temporary
spare tires when necessary, but reduced speeds are
recommended.
Radial-ply tires have the same load-carrying capac-
ity as other types of tires of the same size. They use
the same recommended inflation pressures.
SPARE TIRE (TEMPORARY)
The compact spare tire is designed for emergency
use only. The original tire should be repaired and re-
installed at the first opportunity. Refer to Owner's
Manual for complete details.
JWHEELS AND TIRES 22 - 1

TIRE CHAINS
Tire snow chains may be used on certain models.
Refer to Owner's Manual for more information.
CLEANING OF TIRES
Steam cleaning may be used for cleaning.
DO NOT use gasoline or wire brush for cleaning.
DO NOT use mineral oil or an oil-based solvent.
PRESSURE GAUGES
High-quality, dial-type, air-pressure gauges are rec-
ommended. After checking with the gauge, replace
valve cap and finger tight.
TIRE INFLATION PRESSURES
Under inflation (Fig. 2) causes rapid shoulder wear
and tire flexing.
Over inflation (Fig. 3) causes rapid center wear and
loss of the tire's ability to cushion shocks.
Improper inflation can cause;
²Uneven wear patterns
²Reduced tread life
²Reduced fuel economy
²Unsatisfactory ride
²Cause the vehicle to drift
Refer to the Owner's Manual for information re-
garding proper tire inflation pressure.
This pressure has been carefully selected to provide
for safe vehicle operation. Tire pressure should becheckedcoldonce per month. Tire pressure de-
creases when the outside temperature drops.
Inflation pressures specified on the placards are al-
wayscold inflation pressure. Cold inflation pres-
sure is obtained after the vehicle has not been
operated for at least 3 hours. Tire inflation pressures
may increase from 2 to 6 pounds per square inch
(psi) during operation.Do notreduce this normal
pressure build-up.
Vehicles loaded to the maximum capacity should
not be driven at continuous speeds above 75 mph
(120 km/h).
WARNING: OVER OR UNDER INFLATED TIRES CAN
AFFECT VEHICLE HANDLING AND CAN FAIL SUD-
DENLY, RESULTING IN LOSS OF VEHICLE CON-
TROL.
REPLACEMENT TIRES
OEM tires provide a proper balance of many fea-
tures such as;
²Ride
Fig. 1 Tire Size Identification
Fig. 2 Under Inflation Wear
Fig. 3 Over Inflation Wear
22 - 2 WHEELS AND TIRESJ

²Noise
²Handling
²Durability
²Tread life
²Traction
²Rolling resistance
²Speed capability
Original equipment tires should be used when re-
placement is needed.
Refer to the placard on the vehicle or the
Owner's Manual for the correct replacement
tire.
Failure to use original or equivalent replacement
tires may adversely affect the handling of the vehicle.
The use of oversize tiresis not recommended.
They may cause interference with vehicle suspension
and steering travel. This can cause tire damage or
failure.
WARNING: FAILURE TO EQUIP THE VEHICLE WITH
TIRES HAVING ADEQUATE LOAD CAPABILITY CAN
RESULT IN SUDDEN TIRE FAILURE.
ROTATION
Tires on the front and rear axles operate at differ-
ent loads and perform different steering, driving, and
braking functions. For these reasons, the tires wear
at unequal rates. They may also develop irregular
wear patterns. These effects can be reduced by rotat-
ing the tires according to the maintenance schedule
in the Owners Manual. This will improve tread life,
traction and maintain a smooth quiet ride.
The suggested method of tire rotation is thesame
side front to rearpattern (Fig. 4). Other rotation
methods can be used, but may not provide the same
tire longevity benefits.
TREAD WEAR INDICATORS
Tread wear indicators are molded into the bottom
of the tread grooves. When tread is 1.6 mm (1/16 in.),
the tread wear indicators will appear as a 13 mm
(1/2 in.) band across the tread width.
Tire replacement is necessary when indicators ap-
pear in two or more grooves Fig. 5).
REPAIRING LEAKS
For proper repairing, a radial tire it must be re-
moved from the wheel. Repairs should only be made
if the puncture is in thetread area(Fig. 6). If out-
side the tread area the tire should be replaced.
Deflate tire completely before dismounting tire
from the wheel. Use lubrication such as a mild soap
solution when dismounting or mounting tire. Use
tools free of burrs or sharp edges.
Before mounting tire on wheel, make sure all rust
scale is removed from the rim. Repaint or seal if nec-
essary.
Fig. 4 Tire Rotation Pattern
Fig. 5 Tread Wear Indicators
Fig. 6 Tire Repair Area
JWHEELS AND TIRES 22 - 3

TIRE NOISE OR VIBRATION
The radial-ply tire on your vehicle is more sensitive
to improper mounting, or imbalance.
To determine if tires are the cause of vibration,
drive the vehicle over a smooth road at different
speeds. Note the effect of acceleration and decelera-
tion on noise level. Differential and exhaust noise
will change in intensity as speed varies. Tire noise
will usually remain constant.
TIRE WEAR PATTERNS
Under inflation will increase wear on the shoulders
of the tire. Over inflation will increase wear at the
center of the tread.Excessive camber causes the tire to run at an angle
to the road. One side of tread is worn more than the
other.
Excessive toe-in or toe-out causes wear on the
tread edges. There is a feathered effect across the
tread (Fig. 7).
Fig. 7 Abnormal Tire Tread Wear Patterns
22 - 4 WHEELS AND TIRESJ