air suspension ISUZU TROOPER 1998 Service Repair Manual

Problem Possible Cause Correction
00 – 4 SERVICE INFORMATION
GENERAL INFORMATION
Since the problems in steering, suspension,
wheels and tires involve several systems, they
must all be considered when diagnosing a
complaint. To identify the symptom, always road
test the vehicle first.
Proceed with the following preliminary inspections
and correct any defects which are found.1. Inspect tires for proper pressure and uneven
wear.
2. Raise vehicle on a hoist and inspect front and
rear suspension and steering linkage for loose
or damaged parts.
3. Spin front wheels. Inspect for out-of-round
tires, out-of-balance tires, loose and/or rough
wheel bearings.
GENERAL TROUBLESHOOTING
Vehicle Pulls
Abnormal or Excessive
Tire Wear
Shimmy, Shake or
Vibration1. Mismatched or uneven tires.
2. Tires not adequately inflated.
3. Broken or sagging springs.
4. Radial tire lateral force.
5. Improper wheel alignment.
6. Brake dragging in one wheel.
7. Loose, bent or broken front or rear
suspension parts.
8. Faulty shock absorbers.
1. Sagging or broken spring.
2. Tire out of balance.
3. Improper wheel alignment.
4. Faulty shock absorber.
5. Hard driving.
6. Overloaded vehicle.
7. Tires not rotated periodically.
8. Worn or loose road wheel bearings.
9. Wobbly wheel or tires.
10. Tires not adequately inflated.
1. Tire or wheel out of balance.
2. Loose wheel bearings.
3. Worn steering linkage ball joints.
4. Worn upper or lower end ball joints.
5. Excessively upper wheel runout.
6. Blister or bump on tire.
7. Excessive loaded radial run out of
tire/wheel assembly.
8. Improper wheel alignment.
9. Loose or worn steering linkage.
10. Loose steering gear.
11. Tires not adequately inflated.
12. Loose, bent or broken front or rear
suspension parts.
13. Faulty shock absorber.
14. Hub bearing preload misadjustment.Replace tire.
Adjust tire pressure.
Replace spring.
Replace tire.
Adjust wheel alignment.
Repair brake.
Tighten or replace the
appropriate suspension part(s).
Replace shock absorber.
Replace spring.
Balance or replace tire.
Check front end alignment.
Replace shock absorber.
Replace tire.
Replace tire and reduce load.
Replace or rotate tire.
Replace wheel bearing.
Replace wheel or tire.
Adjust the pressure.
Balance wheels or replace
tire/or wheel.
Replace wheel bearing.
Replace ball joints.
Replace ball joints.
Repair or replace wheel
and/or tire.
Replace tire.
Replace tire or wheel.
Check wheel alignment.
Tighten or replace steering
linkage.
Tighten housing bolts.
Adjust tire pressure.
Tighten or replace the
appropriate suspension parts.
Replace shock absorber.
Adjust preload.

SERVICE INFORMATION 00 – 5
Problem Possible Cause Correction
GENERAL TROUBLESHOOTING (CONT.)
Wheel Tramp or Hop
Hard Steering
Too Much Play In
Steering
Poor Steering Wheel
Returnability
Abnormal Noise1. Blister or bump on tire.
2. Improper shock absorber operation
1. Bind in steering linkage ball studs,
upper or lower end ball joint.
2. Improper wheel alignment.
3. Steering gear misadjustment.
4. Tire not adequately inflated.
5. Bind in steering column or shaft.
6. Improper power steering system
operation.
1. Wheel bearings worn.
2. Loose steering gear or linkage.
3. Steering gear misadjustment.
4. Worn or loose steering shaft universal
joint.
5. Worn steering linkage ball joints.
6. Worn upper or lower end ball joints.
1. Bind in steering linkage ball joints.
2. Bind in upper or lower end ball joints.
3. Bind in steering column and shaft.
4. Bind in steering gear.
5. Improper wheel alignment.
6. Tires not adequately inflated.
7. Loose steering wheel nut.
8. Worn wheel bearing.
1. Worn, sticky or loose upper or lower
end ball joint, steering linkage ball
joints or drive axle joints.
2. Faulty shock absorbers.
3. Worn upper or lower control arm bushing.
4. Loose stabilizer bar.
5. Loose wheel nuts.
6. Loose suspension bolts or nuts.
7. Broken or otherwise damaged wheel
bearings.
8. Broken suspension springs.
9. Loose steering gear.
10. Faulty steering gear.Replace tire.
Replace shock absorber.
Replace ball joints.
Check wheel alignment.
Check and adjust steering gear
preload.
Inflate tires to proper pressure.
Repair or replace.
Repair or replace.
Refer to "Power steering
system troubleshooting."
Replace wheel bearings.
Retighten or repair.
Inspect and adjust steering
gear preload.
Retighten or replace steering
shaft.
Replace ball joints.
Replace ball joints.
Replace ball joints.
Replace ball joints.
Repair or replace.
Check and repair steering gear.
Adjust wheel alignment.
Adjust tire pressure.
Retighten.
Replace.
Replace.
Replace or repair.
Replace.
Retighten bolts.
Tighten nuts. Check for
elongated wheel nut holes.
Replace wheel if required.
Retighten suspension bolts or
nuts.
Replace wheel bearing.
Replace spring.
Retighten mounting bolt.
Check and adjust steering gear.

00 – 6 SERVICE INFORMATION
Problem Possible Cause Correction
GENERAL TROUBLESHOOTING (CONT.)
Wandering or Poor
Steering Stability
Erratic Steering When
Bracking
Low or Uneven Trim
Height
Suspension Bottoms
Body Leans
Cupped Tires1. Mismatched or unevenly worn tires.
2. Loose steering linkage ball joints.
3. Faulty shock absorbers.
4. Loose stabilizer bar.
5. Broken or sagging springs.
6. Steering gear misadjustment.
7. Improper wheel alignment.
1. Worn wheel bearings.
2. Broken or sagging springs.
3. Leaking caliper.
4. Warped discs.
5. Badly worn brake pads.
6. Tires are inflated unequally.
1. Broken or sagging springs.
2. Vehicle overloaded.
3. Incorrect springs.
1. Vehicle overloaded.
2. Faulty shock absorber.
3. Incorrect, broken or sagging springs.
1. Loose stabilizer bar.
2. Faulty shock absorbers, struts or
mounting.
3. Broken or sagging springs.
4. Vehicle overloaded.
1. Worn wheel bearings.
2. Excessive tire or wheel runout.
3. Worn ball joints.
4. Tire out of balance.Replace tire or inflate tires to
proper pressure.
Replace ball joints.
Replace shock absorber.
Tighten or replace stabilizer bar
or bushings.
Replace spring (pairs).
Check or adjust steering gear.
Adjust wheel alignment.
Replace wheel bearings.
Replace spring (pairs).
Repair or replace caliper.
Replace brake disc.
Replace brake pads.
Inflate tires to proper pressure.
Replace springs (In pairs)
Reduce load.
Adjust or replace torsion bar.
Reduce load.
Replace shock absorber.
Replace springs.
Tighten stabilizer bar bolts or
replace bushings.
Replace shock absorber.
Replace springs (In pairs)
Reduce load.
Replace wheel bearings.
Replace tire or wheel.
Replace ball joints.
Adjust tire balance.

POWER STEERING 2A – 11
•If the pressure recorded is lower than 9300
kPa (1350 psi) For 6VD1, 6VE1, and 9800 kPa
(100 kg/cm
2/ 1420 psi) For 4JG2, 4JX1, the
valve or the rotating group in the pump is
defective.
7. If the pump pressure are within specifications,
leave the valve open and turn (or have
someone else turn) the steering wheel fully in
both directions. Record the highest pressures
and compare with the maximum pump
pressure recorded in step 6. If this pressure cannot be built in either (or one) side of the
power steering gear, the power steering gear is
leaking internally and must be disassembled
and repaired.
8. Shut the engine off, remove the testing gage,
reconnect the pressure hose, check the fluid
level and make the needed repairs.
9. If the problem still exists, the steering and front
suspension must be thoroughly examined.

FRONT SUSPENSION 3C – 3
ON-VEHICLE SERVICE
SHOCK ABSORBER
Removal Steps
1. Bolt, nut and washer
2. Nut
3. Rubber bushing and washer
4. Shock absorber
5. Rubber bushing and washer
Installation Steps
5. Rubber bushing and washer
4. Shock absorber
3. Rubber bushing and washer
2. Nut
1. Bolt, nut and washer
REMOVAL
Preparation:
1) Raise the vehicle and support it with suitable safety
stands.
2) Remove wheel and tire assembly. Refer to “Wheels
and Tires” in section 3E.
1. Bolt, Nut and Washer
2. Nut
3. Rubber Bushing and Washer
4. Shock Absorber
5. Rubber Bushing and Washer
INSPECTION AND REPAIR
Make necessary correction or parts replacement if wear,
damage, corrosion or any other abnormal condition are
found through inspection.
•Shock absorber
•Rubber bushing

3C – 6 FRONT SUSPENSION
INSPECTION AND REPAIR
Make necessary correction or parts replacement if wear,
damage, corrosion or any other abnormal condition are
found through inspection.
•Stabilizer bar
•Rubber bushing
•Link ball joint
INSTALLATION
5. Rubber Bushing
4. Stabilizer Bar
3. Bracket
Bracket Nut Torque N·m (kg·m/lb·ft)
22 (2.2 / 16)
2. Link
1. Nut and Washer
Link Nut Torque N·m (kg·m/lb·ft)
50 (5.1 / 37)

3C – 8 FRONT SUSPENSION
2. Height Control Arm
Apply the setting marks to the height control arm and
torsion bar.
3. Torsion Bar
Apply the setting marks to the torsion bar and lower
control arm.
INSPECTION AND REPAIR
Make necessary correction or parts replacement if wear,
damage, corrosion or any other abnormal condition are
found through inspection.
Check the following parts:
•Torsion bar
•Height control arm
•Adjust bolt
•Rubber seat
INSTALLATION
3. Torsion Bar
Make sure the bars are on their correct respective
sides.
Apply grease to the serrated portions.

3C – 12 FRONT SUSPENSION
10. Knuckle
INSPECTION AND REPAIR
Make necessary correction or parts replacement if wear,
damage, corrosion or any other abnormal condition are
found through inspection.
Check the following parts:
•Knuckle
•Needle bearing
•Thrust washer
INSTALLATION
10. Knuckle
9. Needle Bearing
Before installation, apply appropriate amount of
multipurpose type grease to the new bearing (Approx.
5 g).
Installer: 5-8840-2128-0 (J-36838) and
5-8840-0007-0 (J-8092)
8. Washer
Apply multipurpose type grease to the thrust washer,
and install it with chamfered side facing knuckle.
7. Oil Seal
Use a new oil seal, and apply multipurpose type
grease to the area surrounded by the lip (approx. 2 g).
After fitting the oil seal to the installer, drive it to the
knuckle using a hammer or bench press until the tool
front face contacts with the thrust washer.
Installer: 5-8840-2406-0 (J-41468)and
5-8840-0007-0 (J-8092)
6. Knuckle Assembly
5. Upper Ball Joint
Tighten the nut to the specified torque, with just
enough additional torque to align cotter pin holes.
Install new cotter pin.
Upper Ball Joint Nut Torque N·m (kg·m/lb·ft)
98 (10.0 / 72)

3C – 16 FRONT SUSPENSION
INSPECTION AND REPAIR
Make necessary parts replacement if wear, damage,
corrosion or any other abnormal conditions are found
through inspection.
Check the following parts:
•Upper control arm
•Bushing
•Fulcrum pin
INSTALLATION
12. Fulcrum Pin
11. Bushing
Installer: 5-8840-0256-0 (J-29755) and
5-8840-2307-0 (J-39376)
10. Plate
9. Nut
Tighten fulcrum pin nut finger-tight.
NOTE:
Torque fulcrum pin nut after adjusting buffer clearance.
Buffer Clearance (T) mm (in)
23 (0.91) Wide Tread
24 (0.94) Narrow Tread
Fulcrum Pin Nut Torque N·m (kg·m/lb·ft)
108 (11.0 / 80)

3C – 20 FRONT SUSPENSION
14. Bushing, Rear
Remover: 5-8840-2124-0 (J-36834)
INSPECTION AND REPAIR
Make necessary correction or parts replacement if wear,
damage, corrosion or any other abnormal condition are
found through inspection.
Check the following parts:
•Lower control arm
•Bushing
INSTALLATION
14. Bushing, Rear
Installer: 5-8840-2124-0 (J-36834)
13. Bushing, Front
Installer: 5-8840-2123-0 (J-36833)