2002 ISUZU AXIOM Service Repair Manual

WHEEL AND TIRE SYSTEM3E±3
Diagnosis
ConditionPossible causeCorrection
Vehicle PullsMismatched or uneven tires.Replace tire.
Tires not adequately inflated.Adjust tire pressure.
Broken or sagging springs.Replace spring.
Radial tire lateral force.Replace tire.
Improper wheel alignment.Adjust wheel alignment.
Brake dragging in one wheel.Repair brake.
Loose, bent or broken front or rear
suspension parts.Tighten or replace the appropriate
suspension part(s).
Faulty shock absorbers.Replace shock absorber.
Parts in power steering valve
defective.Replace power steering unit.
Abnormal or Excessive Tire WearSagging or broken spring.Replace spring.
Tire out of balance.Balance or replace tire.
Improper wheel alignment.Check front end alignment.
Faulty shock absorber.Replace shock absorber.
Hard driving.Replace tire.
Overloaded vehicle.Replace tire and reduce load.
Tires not rotated periodically.Replace or rotate tire.
Worn or loose road wheel bearings.Replace wheel bearing.
Wobbly wheel or tires.Replace wheel or tire.
Tires not adequately inflated.Adjust the pressure.
Wheel HopBlister or bump on tire.Replace tire.
Improper shock absorber operation.Replace shock absorber.
Shimmy, Shake or VibrationTire or wheel out of balance.Balance wheels or replace tire/or
wheel.
Loose wheel bearings.Replace wheel bearing.
Worn steering linkage ball joints.Replace ball joints.
Worn upper or lower end ball joints.Replace ball joints.
Excessive wheel runout.Repair or replace wheel and/or tire.
Blister or bump on tire.Replace tire.
Excessive loaded radial runout of
tire/wheel assembly.Replace tire or wheel.
Improper wheel alignment.Check wheel alignment.
Loose or worn steering linkage.Tighten or replace steering linkage.
Loose steering unit.Tighten steering unit.
Tires not adequately inflated.Adjust tire pressure.
Loose, bent or broken front or rear
suspension parts.Tighten or replace the appropriate
suspension parts.
Faulty shock absorber.Replace shock absorber.
Hub bearing preload misadjustment.Adjust preload.
Parts in power steering valve
defective.Replace power steering unit.

3E±4WHEEL AND TIRE SYSTEM
Condition CorrectionPossible cause
Hard SteeringBind in steering linkage ball studs,
upper or lower ball joint.Replace ball joint.
Improper wheel alignment.Check wheel alignment.
Tire not adequately inflated.Inflate tires to proper pressure.
Bind in steering column or shaft.Repair or replace.
Improper power steering system
operation.Repair or replace. Refer to Steering
section.
Too Much Play In SteeringWheel bearings worn.Replace wheel bearings.
Loose steering unit or linkage.Retighten or repair.
Worn or loose steering shaft
universal joint.Retighten or replace steering shaft.
Worn steering linkage ball joints.Replace ball joints.
Worn upper or lower end ball joints.Replace ball joints.
Poor Steering Wheel ReturnabilityBind in steering linkage ball joints.Replace ball joints.
Bind in upper or lower ball joints.Replace ball joints.
Bind in steering column and shaft.Repair or replace.
Bind in steering gear.Check and repair steering gear.
Improper wheel alignment.Adjust wheel alignment.
Tires not adequately inflated.Adjust pressure.
Loose steering wheel nut.Retighten.
Worn wheel bearing.Replace.
Abnormal NoiseWorn, sticky or loose upper or lower
ball joint, steering linkage ball joints
or drive axle joints.Replace.
Faulty shock absorbers.Replace.
Worn upper or lower control arm
bushing.Replace.
Loose stabilizer bar.Retighten bolts or replace bushings.
Loose wheel nuts.Tighten nuts. Check for elongated
wheel nut holes. Replace wheel if
required.
Loose suspension bolts or nuts.Retighten suspension bolts or nuts.
Broken or otherwise damaged wheel
bearings.Replace wheel bearing.
Broken suspension springs. Replace spring.
Loose steering unit. Retighten mounting bolt.
Faulty steering unit.Replace steering unit.
Wandering or Poor Steering StabilityMismatched or unevenly worn tires.Replace tire or inflate tires to proper
pressure.
Loose steering linkage ball joints.Replace ball joints.
Faulty shock absorbers.Replace shock absorber.
Loose stabilizer bar.Tighten or replace stabilizer bar or
bushings.
Broken or sagging springs.Replace spring (pairs).
Improper wheel alignment.Adjust wheel alignment.

WHEEL AND TIRE SYSTEM3E±5
Condition CorrectionPossible cause
Erratic Steering When BrakingWorn wheel bearings.Replace wheel bearings.
Broken or sagging springs.Replace spring (pairs).
Leaking caliper.Repair or replace caliper.
Warped discs.Replace brake disc.
Badly worn brake pads.Replace brake pads.
Tires are inflated unequally.Inflate tires to proper pressure.
Low or Uneven Trim HeightBroken or sagging springs.Replace springs (In pairs).
Vehicle overloaded.Reduce load.
Incorrect springs.Adjust or replace torsion bar.
Suspension BottomsVehicle overloaded. Reduce load.
Faulty shock absorber.Replace shock absorber.
Incorrect, broken or sagging springs.Replace springs.
Body LeansLoose stabilizer bar.Tighten stabilizer bar bolts or replace
bushings.
Faulty shock absorber, struts or
mounting.Replace shock absorber.
Broken or sagging springs.Replace springs (In pairs).
Vehicle overloaded.Reduce load.
Cupped TiresWorn wheel bearings.Replace wheel bearing.
Excessive tire or wheel run out.Replace tire or wheel.
Worn ball joints.Replace ball joints.
Tire out of balance.Adjust tire balance.
Irregular and Premature Wear
480RS001
Irregular and/or premature wear has many causes.
Some of them are incorrect inflation pressures, lack of tire
rotation, poor driving habits or improper wheel alignment.
Incorrect inflation is common cause of tire premature
wear.NOTE: Due to their design, radial tires tend to wear faster
in the shoulder area, particularly on the front tires. This
makes regular rotation especially necessary. After
rotation, be sure to check wheel nut torque, and set tire
pressures.

3E±6WHEEL AND TIRE SYSTEM
Tire Rotation
Tire rotation is recommended to equalize wear for longer
tire life.
480RS002
Legend
(1) Spare Tire
If the following conditions are noted, rotate the tires:

Front tire wear is different from rear.

Uneven wear exists across the tread of any tire.

Left and right front tire wear is unequal.

Left and right rear tire wear is unequal.
Check wheel alignment if the following conditions are
noted:

Left and right front tire wear is unequal.

Wear is uneven across the tread of any front tire.

Front tire treads have a scuffed appearance with
ªfeatherº edges on one side of the tread ribs or blocks.
Tread Wear Indicators
480RS006The original equipment tires have built-in tread wear indi-
cators(1) to show when tires need replacement. Theseindicators may appear as wide bands. When the indica-
tors appear in two or more grooves at three locations, tire
replacement is recommended.
Inflation of Tires
710RW002Tire pressure, in cold condition (after vehicle has set for
three hours or more, and driven less than one mile),
should be checked monthly or before any extended trip.
Tire pressure increases approximately 15% when the
tires become hot during driving. Tire pressure specifica-
tion is shown on the label located on the left door lock pil-
lar.
NOTE: Check the tire pressure whenever irregular wear
is found. Tire inflation greatly affects tire wear. If the
alignment check does not reveal any alignment problems,
check the condition of the shock absorbers and wheel/tire
balance.
Diagnosis List
If the following conditions are noted, rotation is required.
1. Front tire wear is different from rear.
2. Uneven wear exists across the tread of any tire.
3. Left and right front tire wear is unequal.
4. Left and right rear tire wear is unequal.
If the following conditions are noted, check the wheel
alignment.
1. Left and right front tire wear is unequal.
2. Uneven wear exists across the tread of any tire.
3. Front tire treads have scuffed appearance with
ªfeatherº edges on one side of tread ribs or blocks.
4. There is cupping, flat spotting etc.
Higher than recommended pressure can cause:
1. Hard ride.
2. Poor steering stability.
3. Rapid and uneven wear at center of the tread.
Lower than recommended pressure can cause:
1. Tire squeal on turns.
2. Hard steering.
3. Rapid and uneven wear on the edges of the tread.
4. Tire rim bruises and rupture.

WHEEL AND TIRE SYSTEM3E±7
5. Tire cord breakage.
6. High tire temperatures.
7. Reduced handling.
8. Reduced fuel economy.
Unequal pressure on same axle can cause:
1. Uneven braking.
2. Steering lead.
3. Reduced handling.
4. Swerve on acceleration.
Radial Tire Waddle
480R200006Waddle is side-to-side movement at the front and/or rear
of the car. It can be caused by the steel belt not being
straight within the tire, or by excessive lateral runout of the
tire or wheel. It is most noticeable at low speed, about 8
to 48 km/h (5 to 30 mph). It may also cause rough ride at
80 to 113 km/h (50 to 70 mph).
The car can be road tested to see which end of the car has
the faulty tire. If the tire causing the waddle is on the rear,
the rear end of the car will ªwaddleº. From the driver's
seat, it feels as if someone is pushing on the side of the
car.
If the faulty tire is on the front, the waddle is more easily
seen. The front sheet metal appears to be moving back
and forth. It feels as if the driver's seat is the pivot point
in the car.
Another more time-consuming method of determining the
faulty tire is substituting tire and wheel assemblies that
are known to be good. Follow these steps:
1. Drive the car to determine if the waddle is coming
from the front or rear.
2. Install tire and wheel assemblies known to be good
(from a similar car) in place of those on the end of the
car which is waddling. If the waddle cannot be
isolated to front or rear, start with the rear tires.
3. Road test again. If improvement is noted, install the
original tire and wheel assemblies one at a time until
the faulty tire is found. If no improvement is noted,
install tires known to be good in place of all four. Then,
install the originals one at a time until the faulty tire is
found.
Radial Tire Lead/Pull
ªLead/Pullº is vehicle deviation from a straight path, on a
level road with no pressure on the steering wheel.
Lead is usually caused by:
1. Poorly manufactured radial tires.
2. Uneven brake adjustment.
3. Wheel alignment.
The way in which a tire is built can produce lead in a car.
An example of this is placement of the belt. Off-center
belts on radial tires can cause the tire to develop a side
force while rolling straight down the road and the tire will
tend to roll like a cone.
The ªRadial Tire Lead/Pull Correctionº chart should be
used to make sure that front wheel alignment is not mis-
taken for tire lead.
Rear tires will not cause lead/pull.

3E±8WHEEL AND TIRE SYSTEM
Radial Tire Lead/Pull Correction Chart
StepActionYe sNo
11. Inflate tires to recommended pressure.
2. Road test vehicle on level uncrowned road.
Was a problem corrected?
End.Go to Step 2
2Switch front tires side to side and road test again.
Was a problem corrected?If roughness
results,replace
tires.
Go to Step 3
3Did the vehicle lead in same direction?Go to Step 4 Go to Step 5
4Put tires back in original position and check alignment.
Was a problem corrected?
End.Go to Step 5
5Install known good tire on one front side.
Was a problem corrected?
Replace tire.
Install a known
good tire in place
of other front tire.
If lead corrected,
replace tire.
Typical examples of abnormal tire ahead wear and major
causes:
CAUTION: Similar wear patterns can be caused by
worn suspension parts, misalignment of wheels and
tires, and other suspension related problems.
Spotty wear ± wear localized on shoulder sections, and
in an extreme cases, the tire becomes polygonal in
shape.
480RW002
1. Tire or wheel out of round or distorted.
2. Hub or knuckle out of round or distorted.
3. Play in hub bearings or ball joint.
4. Rotating parts out of balance.Tread wear one-sided.
480RW003
1. Rotating parts out of balance.
2. Tire or wheel out of round.
3. Hub or knuckle out of round or distorted.

WHEEL AND TIRE SYSTEM3E±9
Localized tread wear.
480RW004
1. Once spotty wear develops in tread due to hard
braking or abrupt starting, localized wear tends to be
promoted.
Shoulder wear (generally wear develops in outer shoul-
der):
480RW005
1. Camber or toe-in incorrect.
2. Shoulder wear caused by repeated hard-cornering.Wear in shoulders at points opposed to each other.
480RW006
1. Tire or wheel out of round or distorted.
2. Play in bearings or ball joint.
Premature wear in shoulders.
480RW007
1. Flexing of tire excessive due to under-inflation.

3E±10WHEEL AND TIRE SYSTEM
One sided feather edging.
480RW008
1. Wear caused by repeated hard cornering.
2. Camber or toe-in incorrect.