2002 ISUZU AXIOM run flat

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.

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±12WHEEL AND TIRE SYSTEM
Tire
Tire Replacement
When replacement is necessary, the original metric tire
size should be used. Most metric tire sizes do not have
exact corresponding alphanumeric tire sizes. It is
recommended that new tires be installed in pairs on the
same axle. If necessary to replace only one tire, it should
be paired with tire having the most tread, to equalize
braking traction.
CAUTION: Do not mix different types of tires such
as radial, bias and bias-belted tires except in
emergencies, because vehicle handling may be
seriously affected and may result in loss of control.
Tire Dismounting
Remove valve cap on valve step and deflate the tire. Then
use a tire changing machine to mount or dismount tires.
Follow the equipment manufacturer's instruction. Do not
use hand tools or tire lever alone to change tires as they
may damage the tire beads or wheel rim.
Tire Mounting
Rim bead seats should be cleaned with a wire brush or
coarse steel wool to remove lubricants, and light rust.
Before mounting a tire, the bead area should be well
lubricated with an approved tire lubricant.
After mounting, inflate the tire to 196kPa (28 psi) so that
beads are completely seated. Inflate the air to specified
pressure and install valve cap to the stem.
WARNING: NEVER STAND OVER TIRE WHEN
INFLATING. BEAD MAY BREAK WHEN BEAD SNAPS
OVER RIM'S SAFETY HUMP AND CAUSE SERIOUS
PERSONAL INJURY.
NEVER EXCEED 240 KPA (35 PSI) PRESSURE WHEN
INFLATING. IF 240 KPA (35 PSI) PRESSURE WILL
NOT SEAT BEADS, DEFLATE, RE-LUBRICATE AND
RE-INFLATE. OVER INFLATION MAY CAUSE THE
BEAD TO BREAK AND CAUSE SERIOUS PERSONAL
INJURY.
Tire Repair
There are many different materials on the market used to
repair tires.
Manufacturers have published detailed instructions on
how and when to repair tires. These instructions can be
obtained from the tire manufacturer if they are not
included with the repair kit.
Wheel Inspection
Damaged wheels and wheels with excessive run-out
must be replaced.
Wheel run out at rim (Base on hub Bore):
Aluminum
1± Vertical play: Less than 0.55 mm (0.022 in)
2± Horizontal play: Less than 0.55 mm (0.022 in)
480RS012
General Balance Procedure
Deposits of mud, etc. must be cleaned from the inside of
the rim.
The tire should be inspected for the following: match
mount paint marks, bent rims, bulges, irregular tire wear,
proper wheel size and inflation pressure. Then balance
according to the equipment manufacturer's
recommendations.
There are two types of wheel and tire balance.
Static balance is the equal distribution of weight around
the wheel.
Assemblies that are statically unbalanced cause a
bouncing action called tramp. This condition will
eventually cause uneven tire wear.

DIFFERENTIAL (REAR)4A2±3
Diagnosis
Many noises that seem to come from the rear axle
actually originate from other sources such as tires, road
surface, wheel bearings, engine, transmission, muffler, or
body drumming. Investigate to find the source of the
noise before disassembling the rear axle. Rear axles, like
any other mechanical device, are not absolutely quiet but
should be considered quiet unless some abnormal noise
is present.
To make a systematic check for axle noise, observe the
following:
1. Select a level asphalt road to reduce tire noise and
body drumming.
2. Check rear axle lubricant level to assure correct level,
and then drive the vehicle far enough to thoroughly
warm up the rear axle lubricant.
3. Note the speed at which noise occurs. Stop the
vehicle and put the transmission in neutral. Run the
engine speed slowly up and down to determine if the
noise is caused by exhaust, muffler noise, or other
engine conditions.
4. Tire noise changes with different road surfaces; axle
noises do not. Temporarily inflate all tires to 344 kPa
(50 psi) (for test purposes only). This will change
noise caused by tires but will not affect noise caused
by the rear axle.
Rear axle nose usually stops when coasting at
speeds under 48 km/h (30 mph); however, tire noise
continues with a lower tone. Rear axle noise usually
changes when comparing pull and coast, but tire
noise stays about the same.
Distinguish between tire noise and rear axle noise by
noting if the noise changes with various speeds or
sudden acceleration and deceleration. Exhaust and
axle noise vary under these conditions, while tire
noise remains constant and is more pronounced at
speeds of 32 to 48 km/h (20 to 30 mph). Further check
for tire noise by driving the vehicle over smooth
pavements or dirt roads (not gravel) with the tires at
normal pressure. If the noise is caused by tires, it will
change noticeably with changes in road surface.
5. Loose or rough front wheel bearings will cause noise
which may be confused with rear axle noise; however,
front wheel bearing noise does not change when
comparing drive and coast. Light application of the
brake while holding vehicle speed steady will often
cause wheel bearing noise to diminish. Front wheel
bearings may be checked for noise by jacking up the
wheels and spinning them or by shaking the wheels to
determine if bearings are loose.
6. Rear suspension rubber bushings and spring
insulators dampen out rear axle noise when correctly
installed. Check to see that there is no link or rod
loosened or metal±to±metal contact.7. Make sure that there is no metal±to±metal contact
between the floor and the frame.
After the noise has been determined to be in the axle, the
type of axle noise should be determined, in order to make
any necessary repairs.
Gear Noise
Gear noise (whine) is audible from 32 to 89 km/h (20 to 55
mph) under four driving conditions.
1. In drive under acceleration or heavy pull.
2. Driving under load or under constant speed.
3. When using enough throttle to keep the vehicle from
driving the engine while the vehicle slows down
gradually (engine still pulls slightly).
4. When coasting with the vehicle in gear and the throttle
closed. The gear noise is usually more noticeable
between 48 and 64 km/h (30 and 40 mph) and 80 and
89 km/h (50 and 55 mph).
Bearing Noise
Bad bearings generally produce a rough growl or grating
sound, rather than the whine typical of gear noise.
Bearing noise frequently ªwow±wowsº at bearing rpm,
indicating a bad pinion or rear axle side bearing. This
noise can be confused with rear wheel bearing noise.
Rear Wheel Bearing Noise
Rear wheel bearing noise continues to be heard while
coasting at low speed with transmission in the neutral.
Noise may diminish by gentle braking. Jack up the rear
wheels, spin them by hand and listen for noise at the
hubs. Replace any faulty wheel bearings.
Knock At Low Speeds
Low speed knock can be caused by worn universal joints
or a side gear hub counter bore in the cage that is worn
oversize. Inspect and replace universal joints or cage and
side gears as required.
Backlash Clunk
Excessive clunk on acceleration and deceleration can be
caused by a worn rear axle pinion shaft, a worn cage,
excessive clearance between the axle and the side gear
splines, excessive clearance between the side gear hub
and the counterbore in the cage, worn pinion and side
gear teeth, worn thrust washers, or excessive drive pinion
and ring gear backlash. Remove worn parts and replace
as required. Select close±fitting parts when possible.
Adjust pinion and ring gear backlash.

4A2±4DIFFERNTIAL (REAR)
Rear Axle Noise
ConditionPossible causeCorrection
Noise in DriveExcessive pinion to ring gear
backlash.Adjust.
Worn pinion and ring gear.Replace
Worn pinion .bearings.Replace.
Loose pinion bearings.Adjust.
Excessive pinion end play.Adjust.
Worn side bearings.Replace.
Loose side bearings.Adjust.
Excessive ring gear run-out.Replace.
Low oil level.Replenish.
Wrong or poor grade oil.Replace.
Bent axle housing.Replace.
Noisy when coastingAxle noise heard when driving will
usually be heard also on coasting,
although not as loud.Adjust or replace.
Pinion and ring gear too tight (audible
when slowing down and disappears
when driving).Adjust.
Intermittent noiseWarped bevel ring.Replace.
Loose differential case bolts.Tighten.
Constant noiseFlat spot on pinion or ring gear teeth.Replace.
Flat spot on bearing.Replace.
Worn pinion splines.Replace.
Worn axle shaft dowel holes.Replace.
Worn hub studs.Replace.
Bent axle shaft.Replace.
Noisy on turnsWorn differential side gears and
pinions.Replace.
Worn differential shaft.Replace.
Worn axle shaft splines.Replace.
Limited Slip Differential
ConditionPossible causeCorrection
Does not lockBroken clutch plates.Replace the clutch plates.
Chatters in turnsLubricant contaminated.Drain lube when hot. Wipe carrier
clean. Refill with lube specified in
Main Data and Specifications at the
end of this section.
Clutch plates dateriorated.Replace clutch plates.
Noise (in addition to normal clutch
engagement)
Broken clutch plates.Replace clutch plates.
engagement)Damaged case.Replace unit.
Broken differential gears.Replace gears.

DRIVE LINE CONTROL SYSTEM (TOD) 4B2±104
StepActionYe sNo
1Are the front and rear tires in specified size?
Go to Step 2
Replace the tires
with specified
ones, and service
the new tires.
Go to
Step 16
2Is the tire pressure correct?
Go to Step 3
Inflate the tires
with specified
pressure.
Go to
Step 16
3Are the tires free from abnormal wear?
Go to Step 4
Replace the tires
with specified
ones, and service
the new tires.
Go to
Step 16
4Are different types of tires used?
Go to Step 5
Replace the tires
with specified
ones, and service
the new tires.
Go to
Step 16
51. Start the engine.
2. Select the TOD switch to the TOD position.
3. Fully turn the steering to the left (or right) end, and select the D
range and start the creep run.
Does the tight corner braking occur? Is the judder with chug-chug
sound observed? * Use caution on the operation.
Go to Step 6 Go to Step 11
61. Select the TOD switch to the 2H position.
2. Fully turn the steering to the left (or right) end, and select the D
range and start the creep run.
Does the tight corner braking occur? Is the judder with chug-chug
sound observed? * Use caution on the operation.
Go to Step 7 Go to Step 14
7Is an LSD mounted to the rear differential? Go to Step 8 Go to Step 9
8Is the genuine LSD oil used in the rear differential?
Go to Step 9
Replace the
differential oil.
Go to
Step 16
9Does the engine output the power correctly?
Go to Step 10
Check the
engine.
Go to
Step 16
10Do the speed sensors work correctly? (Check trouble codes.)The ECU has
failed. Replace
the ECU.
Go to
Step 16
Replace the
speed sensors.
Go to
Step 16
11Is the tight corner braking observed only when the brake is
applied?
Go to Step 12
Conduct full
steering under
WOT.
Go to
Step 5
121. Turn on the starter switch.
Is 8 ~ 10 V observed between terminals 33 and 47?
Go to Step 13
Repair the circuit
of the ECU
connector
terminal 33 (ABS
IN).
Go to
Step 16

5C±6
POWER±ASSISTED BRAKE SYSTEM
Diagnosis
Road Testing The Brakes
Brake Test
Brakes should be tested on a dry, clean, reasonably
smooth and level roadway. A true test of brake
performance cannot be made if the roadway is wet,
greasy or covered with loose dirt where all tires do not grip
the road equally. Testing will also be adversely affected if
the roadway is crowned so as to throw the weight of the
vehicle toward wheels on one side or if the roadway is so
rough that wheels tend to bounce. Test the brakes at
different vehicle speeds with both light and heavy pedal
pressure; however, avoid locking the wheels and sliding
the tires. Braking without locking the tires will stop the
vehicle in less distance than braking to a skid (which has
no brake efficiency). More tire to road friction is present
while braking without locking the tires than braking to a
skid.
The standard brake system is designed and balanced to
avoid locking the wheels except at very high deceleration
levels.
It is designed this way because the shortest stopping
distance and best control is achieved without brake
lock±up.
Because of high deceleration capability, a firmer pedal
may be felt at higher deceleration levels.
External Conditions That Affect Brake Performance
1. Tires: Tires having unequal contact and grip on the
road will cause unequal braking. Tires must be
equally inflated, identical in size, and the thread
pattern of right and left tires must be approximately
equal.
2. Vehicle Loading: A heavily loaded vehicle requires
more braking effort.
3. Wheel Alignment: Misalignment of the wheels,
particularly in regard to excessive camber and caster,
will cause the brakes to pull to one side.
Brake Fluid Leaks
With engine running at idle and the transmission in
ªNeutralº, depress the brake pedal and hold a constant
foot pressure on the pedal. If pedal gradually falls away
with the constant pressure, the hydraulic system may be
leaking.
Check the master cylinder fluid level. While a slight drop in
the reservoir level will result from normal lining wear, an
abnormally low level in reservoir indicates a leak in the
system. The hydraulic system may be leaking internally
as well as externally. Refer to
Master Cylinder Inspection.
Also, the system may appear to pass this test but still
have slight leakage. If fluid level is normal, check the
vacuum booster push rod length. If an incorrect length
push rod is found, adjust or replace the push rod. Check
the brake pedal travel and the parking brake adjustment.
When checking the fluid level, the master cylinder fluid
level may be lower than the ªMAXº mark if the front and
rear linings are worn. This is normal.
Warning Light Operation
When the ignition switch is in the START position, the
ªBRAKEº warning light should turn on and go off when the
ignition switch returns to the ON position.
The following conditions will activate the ªBRAKEº light:
1. Parking brake applied. The light should be on
whenever the parking brake is applied and the ignition
switch is on.
2. Low fluid level. A low fluid level in the master cylinder
will turn the ªBRAKEº light on.
3. During engine cranking the ªBRAKEº light should
remain on. This notifies the driver that the warning
circuit is operating properly.

5C±7 POWER±ASSISTED BRAKE SYSTEM
General Diagnosis
ConditionPossible causeCorrection
Brake PullTire inflation pressure is unequal.Adjust
Front wheel alignment is incorrect.Adjust
Unmatched tires on same axle.Tires with approx. the same amount
of tread should be used on the same
axle.
Restricted brake pipes or hoses.Check for soft hoses and damaged
lines. Replace with new hoses and
new doubleªwalled steel brake
piping.
Water or oil on the brake pads.Clean or replace.
Brake pads hardened.Replace
Brake pads worn excessively.Replace
Brake rotor worn or scored.Grind or replace.
Disc brake caliper malfunctioning.Clean or replace.
Front hub bearing preload incorrect.Adjust or replace.
Loose suspension parts.Check all suspension mountings.
Loose calipers.Check and tighten the bolts to
specifications.
Brake Roughness or Chatter
(Pulsates)Excessive lateral runout.Check per instructions. If not within
specifications, replace or machine
the rotor.
Parallelism not within specifications.Check per instructions. If not within
specifications, replace or machine
the rotor.
Wheel bearings not adjusted.Adjust wheel bearings to correct
specifications
Pad reversed (steel against iron).Replace the brake pad and machine
rotor to within specifications.
Excessive Pedal EffortMalfunctioning vacuum booster.Check the vacuum booster operation
and repair, if necessary.
Partial system failure.Check the front and rear brake
system for failure and repair. Also,
check the brake warning light. If a
failed system is found, the light
should indicate failure.
Excessively worn pad.Check and replace pads in sets.
Piston in caliper stuck or sluggish.Remove caliper and rebuild.
Fading brakes due to incorrect pad.Remove and replace with original
equipment pad or equivalent.
Vacuum leak to vacuum booster.Check for ruptured or loose hose.
Check the direction of check valve
within vacuum hose.Correct vacuum hose direction.
Grease on the brake pads.Replace or clean.