1998 ISUZU TROOPER wheel size

SUPPLEMENTAL RESTRAINT SYSTEM STEERING WHEEL & COLUMN 2A – 51
SECTION 2A
SUPPLEMENTAL RESTRAINT SYSTEM
STEERING WHEEL & COLUMN
CAUTION:
When fasteners are removed, always reinstall them at the same location from which
they were removed. If a fastener needs to be replaced, use the correct part number
fastener for that application. If the correct part number fastener is not available, a
fastener of equal size and strength (or stronger) may be used. Fasteners that are not
reused, and those requiring thread locking compound, will be called out. The correct
torque value must be used when installing fasteners that require it. If the above
conditions are not followed, parts or system damage could result.
CONTENTS
PAGE
General Description ......................................................................................................... 2A – 52
On-Vehicle Service ........................................................................................................... 2A – 53
SRS Connectors ........................................................................................................... 2A – 53
Inflator Module Replacement ..................................................................................... 2A – 54
Steering Wheel Replacement ..................................................................................... 2A – 57
Combination Switch Replacement ............................................................................ 2A – 60
Lock Cylinder Replacement ........................................................................................ 2A – 64
Steering Column Replacement .................................................................................. 2A – 69

3E – 2 WHEELS AND TIRES
GENERAL DESCRIPTION
Replacement wheels or tires must be equivalent to
the originals in load capacity, specified dimension
and mounting configuration. Improper size or type
may affect bearing life, brake performance,
speedometer/odometer calibration, vehicle ground
clearance and tire clearance to the body and
chassis.All models are equipped with metric sized steel
belted radial tires. Correct tire pressures and
driving habits have an important influence on tire
life. Heavy cornering, excessively rapid
acceleration and unnecessary sharp braking
increase premature and uneven wear.

3E – 4 WHEELS AND TIRES
TIRES
REPLACEMENT
When replacement is necessary, the original metric 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 MOUNTING
Remove valve cap on valve stem 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 DISMOUNTING
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 196 kPa (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.
UNIT REPAIR

WHEELS AND TIRES 3E – 5
WHEELS
REPLACEMENT
Damaged wheels and wheels with excessive runout must
be replaced.
Wheel Runout at Rim (Based on Hub bore.)
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.
Dynamic balance is the equal distribution of weight on
each side of the wheel center-line so that when the tire
spins there is not tendency for the assembly to move from
side to side. Assemblies that are dynamically unbalanced
may cause shimmy.
WARNING:
STONES SHOULD BE REMOVED FROM THE TREAD TO
AVOID OPERATOR INJURY DURING SPIN BALANCING
AND TO OBTAIN A GOOD BALANCE.
Steel Aluminum
AVertical play:
Less than mm(in)1.5 (0.059) 0.7 (0.028)
BHorizontal play:
Less than mm(in)1.5 (0.059) 0.7 (0.028)

DIFFERENTIAL (REAR 220mm)
4A2A±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
(3.5kg/cm
2, 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 noise 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. Driving 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 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.

DIFFERENTIAL (REAR 244mm)
4A2B±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
(3.5kg/cm
2, 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 noise 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. Driving 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 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.

POWER ASSISTED BRAKE SYSTEM 5C – 3
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 so that 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. Locked
wheels and sliding tires do not indicate brake
efficiency, since heavily braked but turning wheels
will stop the vehicle in less distance than locked
wheels. More tire-to-road friction is present with a
heavily braked turning tire then with a sliding tire.
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 tread
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
“Neutral”, 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 reservoir level will result from normal lining
wear, an abnormally low level in resevoir 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

POWER ASSISTED BRAKE SYSTEM 5C – 11
12. Reconnect the brake pipe 1to the master cylinder
and tighten the pipe.
13. Depress the brake pedal slowly once and hold it
depressed.
14. Loosen the rear wheel brake pipe 1at the master
cylinder.
15. Retighten the brake pipe, then release the brake
pedal slowly.
16. Repeat steps 13 through 15 until no air comes out
from the port when the brake pipe is loosened.
NOTE:
Be very careful not to allow the brake fluid to come in
contact with painted surfaces.
17. Bleed the air from the front wheel brake pipe
connection 2by repeating steps 7 through 16.
Bleeding the Caliper
18. Bleed the air from each wheel in the order listed
below.
LHD models:
1) Right rear caliper
2) Left rear caliper
3) Load sensing proportioning valve (only for
Europe and South Africa)
4) Right front caliper
5) Left front caliper
RHD models:
1) Left rear caliper
2) Right rear caliper
3) Load sensing proportioning valve (only for
Europe and South Africa)
4) Left front caliper
5) Right front caliper
Conduct air bleeding from the wheels in the above
order. If no brake fluid comes out, it suggests that air
is mixed in the master cylinder. In this case, bleed air
from the master cylinder in accordance with Steps 7
through 17, and then bleed air from the caliper.
19. Place the proper size box end wrench over the
bleeder screw.
20. Cover the bleeder screw with a transparent tube,
and submerge the free end of the transparent tube
in a transparent container containing brake fluid.
21. Pump the brake pedal slowly three (3) times
(once/sec), then hold it depressed.
22. Loose the bleeder screw until fluid flows through
the tube.
23. Retighten the bleeder screw.
24. Release the brake pedal slowly.
25. Repeat step 21 through 24 until the air is
compeletely removed. It may be necessary to
repeat the bleeding procedure 10 or more times
for front wheels and 15 or more times for rear
wheels.
26. Go to the next wheel in the sequence after each
wheels is bled. Be sure to monitor reservoir fluid
level.