Brake drum ISUZU AXIOM 2002 Service Repair Manual

0B±6MAINTENANCE AND LUBRICATION
Always change the oil and the oil filter as soon as possible
after driving in a dust storm.
Engine Cooling System Inspection
Inspect the coolant/anti±freeze. If the coolant is dirty or
rusty, drain, flush and refill with new coolant. Keep coolant
at the proper mixture for proper freeze protection,
corrosion inhibitor level and best engine operating
temperature. Inspect hoses and replace if cracked,
swollen or deteriorated. Tighten the hose clamps if
equipped with screw±type clamps. Clean outside of
radiator and air conditioning condenser. Wash filler cap
and neck. To help ensure proper operation, a pressure
test of both the cooling system and the cap is also
recommended.
Exhaust System Inspection
Visually inspect the exhaust pipes, muffler, heat shields
and hangers for cracks, deterioration, or damage.
Be alert to any changes in the sound of the exhaust
system or any smell of fumes. These are signs the system
may be leaking or overheating. Repair the system at
once, if these conditions exist. (See also ªEngine Exhaust
Gas Safetyº and ªThree Way Catalytic Converterº in the
Owner's manual.)
Fuel Cap, Fuel Lines, and Fuel Tank
Inspection
Inspect the fuel tank, the fuel cap and the fuel lines every
60,000 miles (96,000 km) for damage which could cause
leakage.
Inspect the fuel cap and the gasket for correct sealing and
physical damage. Replace any damaged parts.
Drive Belt Inspection
Check the serpentine belt driving for cracks, fraying,
wear, and correct tension every 30,000 miles (48,000
km). Replace as necessary.
Wheel Alignment, Balance and Tires
Operation
Uneven or abnormal tire wear, or a pull right or left on a
straight and level road may show the need for a wheel
alignment. A vibration of the steering wheel or seat at
normal highway speeds means a wheel balancing is
needed. Check tire pressure when the tires are ªcoldº
(include the spare).
Maintain pressure as shown in the tire placard, which is
located on the driver's door lock pillar.
Steering System Operation
Be alert for any changes in steering operation. An
inspection or service is needed when the steering wheel
is harder to turn or has too much free play, or if there are
unusual sounds when turning or parking.
Brake Systems Operation
Watch for the ªBRAKEº light coming on. Other signs of
possible brake trouble are such things as repeated pulling
to one side when braking, unusual sounds when braking
or between brake applications, or increased brake pedaltravel. If you note one of these conditions, repair the
system at once.
For convenience, the following should be done when
wheels are removed for rotation: Inspect lines and hoses
for proper hookup, bindings, leaks, crack, chafing etc.
Inspect disc brake pads for wear and rotors for surface
condition.
Inspect other brake parts, including parking brake drums,
linings etc., at the same time. Check parking brake
adjustment.
Inspect the brakes more often if habit or conditions
result in frequent braking.
Parking Brake and Transmission Park
Mechanism Operation
Park on a fairly steep hill and hold the vehicle with the
parking brake only. This checks holding ability. On
automatic transmission vehicles, shifting from ªPº
position to the other positions cannot be made unless the
brake pedal is depressed when the key switch is in the
ªONº position or the engine is running.
WARNING: B E F O R E C H E C K I N G T H E S TA R T E R
SAFETY SWITCH OPERATION BELOW, BE SURE TO
HAVE ENOUGH ROOM AROUND THE VEHICLE.
THEN FIRMLY APPLY BOTH THE PARKING BRAKE
AND THE REGULAR BRAKE. DO NOT USE THE
ACCELERATOR PEDAL. IF THE ENGINE STARTS,
BE READY TO TURN OFF THE KEY PROMPTLY.
TAKE THESE PRECAUTIONS BECAUSE THE
VEHICLE COULD MOVE WITHOUT WARNING AND
POSSIBLY CAUSE PERSONAL INJURY OR
PROPERTY DAMAGE.
Starter Safety Switch Operation
Check by trying to start the engine in each gear while
setting the parking brake and the foot brake. The starter
should crank only in ªPº (Park) or ªNº (Neutral).
Accelerator Linkage Lubrication
Lubricate the accelerator pedal fulcrum pin with chassis
grease.
Steering and Suspension Inspection
Inspect the front and rear suspension and steering
system for damaged, loose or missing parts or signs of
wear. Inspect power steering lines and hoses for proper
hookup, binding, leaks, cracks, chafing, etc.
Body and Chassis Lubrication
Lubricate the key lock cylinders, the hood latch, the hood
and door hinges, the door check link, the parking cable
guides, the underbody contact points, and the linkage.
Propeller Shaft Inspection and Lubrication
Check the propeller shaft flange±to±pinion bolts for
proper torque to 63 Nwm (46 lb ft) for front and rear
propeller shaft.

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.

DIFFERENTIAL (REAR)4A2±7
Installation
1. Install brake pipe.
2. Connect Antilock brake system (ABS) speed sensor
and harness, refer to
4±Wheel Anti±Lock Brake
System (ABS) in Brake
section.
3. Install brake disc.
4. Install brake caliper. Refer to
Disk Brakes in Brake
section.
5. Install axle housing assembly.
6. Install coil spring and insulator.
7. Install the lower link fixing bolt and nut to the axle
housing. For the procedures in items 7±11, refer to
Suspension section.
8. Install the upper link bolt and nut to the axle housing.9. Install the lateral rod fixing nut and bolt to the frame
side.
10. Install the stabilizer linkage mounting nut and bolt to
the frame side.
11. Install the shock absorber.
12. Install brake tube flare nut, Refer to
Disk Brakes in
Brake
section.
13. Install ABS connector and bracket.
14. Connect breather hose.
15. Install parking brake cable, Refer to
Parking Brakes in
Brake
section.
16. Bleed brakes. Refer to
Hydraulic Brakes in Brake
section.
Axle Shaft, Oil Seal and Bearing
Axle Shaft and Associated Parts
Disc Brake Model
420RW008
Legend
(1) Axle Shaft
(2) Backing Plate
(3) Oil Seal
(4) Bearing
(5) Axle Housing
(6) Lock Washer
(7) Nut
Drum Brake Model
420RX001
Legend
(1) Axle Shaft
(2) Backing Plate
(3) Oil Seal
(4) Bearing
(5) Axle Housing
(6) Lock Washer
(7) Nut

4A2±8DIFFERNTIAL (REAR)
Removal
1. Raise the vehicle.
2. Remove rear wheels and brake calipers or drums.
Do not let calipers hang from the vehicle by the brake
line or hose. Use a wire to hang the caliper to the
frame to prevent damage to the caliper.
3. Remove four nuts and lockwashers.
4. Remove shaft assembly from the axle housing.
5. Remove snap ring and bearing cup.
6. Break retainer ring with hammer and chisel.
420RS026
7. Break bearing cage with hammer and chisel.
420RS027
8. Remove oil seal, retainer, and emergency brake
assembly.
9. Remove inner race from shaft with OTC±1126
bearing splitter and press.
420RS028
Inspection

Shaft for spalling or grooves from seal wear.

Retainer ± bent or damaged.

Replace items if required.
Installation
1. Emergency brake assembly.
2. Install retainer.
Note direction ± do not install backwards.
420RS029

5A±11
BRAKE CONTROL SYSTEM
Acronyms and Abbreviations
Several acronyms and abbreviations are commonly used
throughout this section:
ABS
Anti-lock Brake System
CIM
Coil Integrated Module
CKT
Circuit
DLC
Data Link Connector
EHCU
Electronic Hydraulic Control Unit
FL
Front Left
FR
Front Right
GEN
Generator
H/U
Hydraulic Unit
MV
Millivolts
RR
Rear
RPS
Revolution per Second
VDC
DC Volts
VA C
AC Volts
W/L
Warning Light
WSS
Wheel Speed Sensor
General Diagnosis
General Information
ABS troubles can be classified into two types, those
which can be detected by the ABS warning light and those
which can be detected as a vehicle abnormality by the
driver.
In either case, locate the fault in accordance with the
ªBASIC DIAGNOSTIC FLOWCHARTº and repair.
Please refer to
Section 5C for the diagnosis of
mechanical troubles such as brake noise, brake judder
(brake pedal or vehicle vibration felt when braking),
uneven braking, and parking brake trouble.
ABS Service Precautions
Required Tools and Items:

Box Wrench

Brake Fluid

Special ToolSome diagnosis procedures in this section require the
installation of a special tool.
J-39200 High Impedance Multimeter
When circuit measurements are requested, use a circuit
tester with high impedance.
Computer System Service Precautions
The Anti-lock Brake System interfaces directly with the
Electronic Hydraulic Control Unit (EHCU) which is a
control computer that is similar in some regards to the
Powertrain Control Module. These modules are designed
to withstand normal current draws associated with
vehicle operation. However, care must be taken to avoid
overloading any of the EHCU circuits. In testing for opens
or shorts, do not ground or apply voltage to any of the
circuits unless instructed to do so by the appropriate
diagnostic procedure. These circuits should only be
tested with a high impedance multimeter (J-39200) or
special tools as described in this section. Power should
never be removed or applied to any control module with
the ignition in the ªONº position.
Before removing or connecting battery cables, fuses or
connectors, always turn the ignition switch to the ªOFFº
position.
General Service Precautions
The following are general precautions which should be
observed when servicing and diagnosing the Anti-lock
Brake System and/or other vehicle systems. Failure to
observe these precautions may result in Anti-lock Brake
System damage.

If welding work is to be performed on the vehicle using
an electric arc welder, the EHCU and valve block
connectors should be disconnected before the
welding operation begins.

The EHCU and valve block connectors should never
be connected or disconnected with the ignition ªONº .

If only the rear wheels are rotated using jacks or drum
tester, the system will diagnose a speed sensor
malfunction and the ªABSº warning light will
illuminate. But actually no trouble exists. After
inspection stop the engine once and re-start it, then
make sure that the ªABSº warning light does not
illuminate.
If the battery has been discharged
The engine may stall if the battery has been completely
discharged and the engine is started via jumper cables.
This is because the Anti-lock Brake System (ABS)
requires a large quantity of electricity. In this case, wait
until the battery is recharged, or set the ABS to a
non-operative state by removing the fuse for the ABS
(50A). After the battery has been recharged, stop the
engine and install the ABS fuse. Start the engine again,
and confirm that the ABS warning light does not light.
Note on Intermittents
As with virtually any electronic system, it is difficult to
identify an intermittent failure. In such a case duplicating
the system malfunction during a test drive or a good
description of vehicle behavior from the customer may be
helpful in locating a ªmost likelyº failed component or

5C±2
POWER±ASSISTED BRAKE SYSTEM
Inspection and Repair 5C±40. . . . . . . . . . . . . . . . . .
Reassembly 5C±40. . . . . . . . . . . . . . . . . . . . . . . . . .
Main Data and Specifications 5C±42. . . . . . . . . . .
Rear Disc Brake Pads (4y4 Model) 5C±43. . . . . . . .
Brake Pads Inspection 5C±43. . . . . . . . . . . . . . . . .
Brake Pads and Associated Parts 5C±43. . . . . . .
Removal 5C±44. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 5C±44. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rear Disc Brake Rotor (4y4 Model) 5C±46. . . . . . . .
Inspection 5C±46. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Replacing Brake Rotors 5C±46. . . . . . . . . . . . . . . .
Refinishing Brake Rotors 5C±46. . . . . . . . . . . . . . .
Rear Drum (In Disc) Inside Diameter Check 5C±47
Rear Disc Brake Caliper Assembly
(4y4 Model) 5C±48. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rear Disc Brake Caliper Assembly and
Associated Parts 5C±48. . . . . . . . . . . . . . . . . . . . . .
Removal 5C±48. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 5C±49. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rear Disc Brake Caliper (4y4 Model) 5C±50. . . . . .
Rear Disc Brake Caliper Disassembled
View 5C±50. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Disassembly 5C±51. . . . . . . . . . . . . . . . . . . . . . . . . .
Inspection and Repair 5C±51. . . . . . . . . . . . . . . . . .
Reassembly 5C±51. . . . . . . . . . . . . . . . . . . . . . . . . .
Main Data and Specifications (4y4 Model) 5C±53
Brake Lining 5C±54. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Brake Lining and Associated Parts 5C±54. . . . . . .
Removal 5C±54. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Brake Lining Inspection 5C±55. . . . . . . . . . . . . . . .
Installation 5C±55. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Drum Brake Adjustment (4y2 Model) 5C±56. . . . .
Servicing The Brake Drum 5C±56. . . . . . . . . . . . . .
Wheel Cylinder Assembly (4y2 Model) 5C±57. . . . .
Wheel Cylinder Assembly and Associated
Parts 5C±57. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Removal 5C±57. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 5C±57. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Disassembled View 5C±58. . . . . . . . . . . . . . . . . . . .
Disassembly 5C±58. . . . . . . . . . . . . . . . . . . . . . . . . .
Inspection and Repair 5C±58. . . . . . . . . . . . . . . . . .
Reassembly 5C±58. . . . . . . . . . . . . . . . . . . . . . . . . .
Main Data and Specifications 5C±60. . . . . . . . . . .
Service Precaution
WARNING: THIS VEHICLE HAS A SUPPLEMENTAL
RESTRAINT SYSTEM (SRS). REFER TO THE SRS
COMPONENT AND WIRING LOCATION VIEW IN
ORDER TO DETERMINE WHETHER YOU ARE
PERFORMING SERVICE ON OR NEAR THE SRS
COMPONENTS OR THE SRS WIRING. WHEN YOU
ARE PERFORMING SERVICE ON OR NEAR THE SRS
COMPONENTS OR THE SRS WIRING, REFER TO
THE SRS SERVICE INFORMATION. FAILURE TO
FOLLOW WARNINGS COULD RESULT IN POSSIBLE
AIR BAG DEPLOYMENT, PERSONAL INJURY, OR
OTHERWISE UNNEEDED SRS SYSTEM REPAIRS.
CAUTION: Always use the correct fastener in the
proper location. When you replace a fastener, use
ONLY the exact part number for that application.
ISUZU will call out those fasteners that require a
replacement after removal. ISUZU will also call out
the fasteners that require thread lockers or thread
sealant. UNLESS OTHERWISE SPECIFIED, do not
use supplemental coatings (Paints, greases, or other
corrosion inhibitors) on threaded fasteners or
fastener joint interfaces. Generally, such coatings
adversely affect the fastener torque and the joint
clamping force, and may damage the fastener. When
you install fasteners, use the correct tightening
sequence and specifications. Following these
instructions can help you avoid damage to parts and
systems.
General Description
Master Cylinder Assembly
330RS001

5C±5 POWER±ASSISTED BRAKE SYSTEM
Leading/Trailing Drum Brakes (4y2 Model)
A05RS003
This drum brake assembly is a leading/trailing shoe
design. Both brake shoes are held against the wheel
cylinder pistons by the upper return spring and to the fixed
anchor plate by the lower return spring. When the brakes
are applied, the wheel cylinder pistons expand pushing
both shoes out contact the drum.
With forward wheel rotation, the forward brake shoe will
wrap into the drum and becomes self-energized.
With reverse wheel rotation, the rear brake shoe is
self-energized. Force from the brake shoes is transferred
to the anchor plate through the braking plate to the axle
flange. Adjustment is automatic and occurs on any
service brake application. Also, with leading/trailing
brakes, it is normal for the front shoe to wear at a faster
rate than the rear shoe.

5C±8
POWER±ASSISTED BRAKE SYSTEM
Condition CorrectionPossible cause
Excessive Brake Pedal TravelAir in hydraulic circuit.Bleed the hydraulic circuit.
Level of brake fluid in the reservoir
too low.Replenish brake fluid reservoir to
specified level and bleed hydraulic
circuit as necessary.
Master cylinder push rod clearance
excessive.Adjust
Leakage in hydraulic system.Correct or replace defective parts.
Brake DragMaster cylinder pistons not returning
correctly.Adjust the stop light switch and
vacuum booster push rod. If
necessary, rebuild.
Restricted brake pipes or hoses.Check for soft hoses or damaged
pipes, and replace with new hoses
and new double±walled steel brake
piping.
Parking brake maladjusted.Adjust
Parking brake lining clearance
insufficient.Adjust
Brake pedal free play insufficient.Adjust the brake pedal height or
power cylinder operating rod.
Piston in the master cylinder sticking.Replace
Piston in the disc brake caliper
sticking.Replace piston seals.
Brake pads sticking in caliper.Clean
Return spring weakened.Replace
Parking brake binding.Overhaul the parking brakes and
correct.
Front hub bearing preload incorrect.Adjust or replace.
Parking brake shoes not returning.Correct or replace the brake back
plate and brake shoe as necessary.
Obstructions in hydraulic circuit.Clean
Rotor warped excessively.Grind or replace.
Rear brake drum distorted.Grind or replace.
Parking cable sticking.Grind or replace.
Grabbing or Uneven Braking Action
(All conditions listed under ªPullsº)Malfunctioning vacuum booster.Check operation and correct as
necessary.
Binding brake pedal mechanism.Check and lubricate, if necessary.
Corroded caliper assembly.Clean and lubricate.
Brake NoisyBrake pads are worn.Replace
Brake pads are hardened.Replace
Brake pads are in poor contact with
rotor.Correct
Brake disc(s) warped, worn or
damaged.Grind or replace.
Disc brake anti±squeak shims
fatigued.Replace
Front hub bearings are loose or
preload is incorrect.Adjust or replace.
Brake disc is rusted.Grind or replace.

5C±47 POWER±ASSISTED BRAKE SYSTEM
After refinishing, replace any rotor that does not meet the
minimum thickness of 16.97 mm (0.668 in). Do not use a
brake rotor that exceeds the manufacturers
specifications.
Minimum wear dimension: 16.6 mm (0.654 in)
Refinish dimension: 16.97 mm (0.668 in)
420RW002
Rear Drum (In Disc) Inside Diameter
Check
Check the rear drum inside diameter by measuring at
more than two portions as shown in the illustration.
If the inside diameter is greater than the limit, replace the
rear rotor.
Standard: 210.0 mm (8.27 in)
Limit: 211.4 mm (8.32 in)
420RS035

5C±54
POWER±ASSISTED BRAKE SYSTEM
Brake Lining
Brake Lining and Associated Parts
305RW001
Legend
(1) Wheel and Tire Assembly
(2) Drum
(3) Hold-down Spring and Cup
(4) Hold-down Spring and Cups
(5) Lower Return Spring
(6) Upper (other) Return Spring
(7) Trailing Shoe Assembly with Parking Brake
Lever
(8) Leading Shoe Assembly with Upper (inner)
Return Spring(9) Upper (inner) Return Spring
(10) Auto Adjuster Lever
(11) Parking Brake Lever
(12) Adjuster Assembly
(13) Wave Washer
(14) Retainer
(15) Hold-down Pin
(16) Hold-down Pin
Removal
1. Raise the vehicle and support with suitable safety
stands.
2. Remove wheel and tire assembly (1).

Refer to
ªWheel and Tiresº in Wheel and Tire
System
section.
3. Remove Drum (2).

If difficulty is encountered in removing the drum:
± Mark the position of the drum to the axle.
± Make sure the parking brake is released.± Use a rubber mallet to tap gently on the outer rim of
the drum and/or around the inner drum. Be careful
to avoid damaging the drum.
4. Remove upper (other) return spring (6) and auto
adjuster lever.
5. Remove lower return spring (5).
6. Remove hold-down spring and cups (4) and
hold-down pin (15).
7. Remove adjuster assembly (12)
8. Remove leading shoe assembly (8) with upper (inner)
return spring (9).