Brake drum ISUZU AXIOM 2002 Service User Guide

5C±55 POWER±ASSISTED BRAKE SYSTEM
NOTE: Do not over stretch the return spring.
305RS003
9. Remove upper (inner) return spring (9).
10. Remove hold-down spring and cup (3) and hold-down
pin (16).
11. Remove Trailing shoe assembly (7) with parking
brake lever (16).
12. Remove parking brake cable from parking brake lever
(11).
13. Remove retainer (14), wave washer (13), and parking
brake lever (11).
Brake Lining Inspection
Check the shoe assemblies for wear by removing brake
drum.
Replace the shoe assemblies, if lining thickness is less
than 1.0 mm (0.039 in).
The shoe assemblies have a wear indicator that makes a
noise when the linings wear to a degree where
replacement is required.
Minimum limit: 1.0 mm (0.039 in)
305RS001
Installation
1. Apply grease lightly to back place A.
305RW002
Legend
(1) Place A (3 portions for each side)
2. Install parking brake lever (11), wave washer (13),
and retainer (14).
3. Install trailing shoe assembly (7) with parking brake
lever (16).
4. Install the parking brake cable to parking brake lever
(11).
5. Install hold-down pin (16) and hold-down spring and
cup (3).
6. Install upper (inner) return spring (9).
7. Install leading shoe assembly (8) with upper (inner)
return spring (9).
NOTE: Do not over stretch the return spring.
305RS003
8. Install adjuster assembly (12).
9. Install hold-down pin (15) and hold-down spring and
cups (4).

5C±56
POWER±ASSISTED BRAKE SYSTEM
10. Install lower return spring (5).

Use brake spring tool.
11. Install auto adjuster lever (10).
12. Install upper (outer) return spring (6).

Use brake spring tool.
13. Install brake drum (2).

Adjust the brakes, refer to
Drum Brake Adjustment
in this section.
14. Install wheel and tire assembly (1).

Refer to
ªWheels and Tires º in wheel and Tire
System
section.
Drum Brake Adjustment (4y2 Model)
NOTE: All brakes are self-adjusting. Brakes are adjusted
by repeated stepping on the brake pedal. (After stepping
on the pedal and releasing it, the rear auto adjuster, in the
rear brake, produces a clicking sound.
The same operation should be repeated until the sound
disappears.)
Take the following steps after overhauling the rear brake
assembly.
1. Move the parking brake handle to its fully released
position.
2. Parking cable must be loosened sufficiently. (Loosen
the adjust nut and the lock nut.)
3. Repeat stepping on the brake pedal firmly, and
releasing it until the clicking sound can no longer be
heard.
If the difference between the brake drum inside
diameter and diameter of the brake shoes is adjusted
to be 0,5 mm, the number of times for depressing the
brake pedal can be reduced.
4. Remove the drum. Measure the brake drum inside
diameter and diameter of the brake shoes.
Shoe clearance: 0.25-0.4 mm (0.0098-0.0157 in)
If incorrect, check the brake auto-adjusting system.
5. Rotate the adjust nut until all slack disappears from
the cable. Set the adjust nut.
6. Applying about 30 kg (66 lb) of force, pull the parking
brake handle to its fully set position three or four
times.
7. If the parking brake is properly adjusted, the travel
between the fully disengaged position and the fully
engaged position will be between 9 and 11 notches.
If the traveling range is not within these limits, again
repeat steps 1 through 5.
After adjusting has been done, check to see if the rear
wheel rotates smoothly without drag when turned by
hand.
Servicing The Brake Drum
Whenever the brake drums are removed, they should be
thoroughly cleaned and inspected for cracks, scores,
deep grooves and out-of-round.
Cracked, Scored or Grooved Drum
A cracked drum is unsafe and must be replaced.
Do not attempt to weld a cracked drum.
Smooth any slight scores. Heavy or extensive scoring will
cause excessive brake lining wear, and it will probably be
necessary to machine the drum braking surface.
If the brake linings are slightly worn and the drum is
grooved, the drum should be polished with fine emery
cloth but should not be machined. At this stage,
eliminating all the grooves in the drum and smoothing the
ridges on the lining would require the removal of too much
metal and lining. If left alone, the grooves and ridges
match and satisfactory service can be obtained. If brake
linings are to be replaced, a grooved drum should be
machined. Using a grooved drum with new linings will
create inefficient braking performance and cause the
linings to wear quicker.
Out-Of-Round Drum
An out-of-round drum makes accurate brake shoe
adjustment impossible and is likely to cause excessive
wear to other parts of the brake mechanism due to its
eccentric action. An out-of-round drum can also cause
severe and irregular tire tread wear as well as a pulsing
brake pedal. When the braking surface of a brake drum
exceeds the specification limit of 0.15 mm (0.006 in) in
out-of-round, the drum should be machined to true up the
braking surface. Out-of-round can be accurately
measured with an inside micrometer fitted with proper
extension rods. When measuring a drum for out-of-round
and wear, take measurements at the open and closed
edges of machines surfaces and at right angles to each
other.
Maximum out-of-round: 0.15 mm (0.006 in)
420RS034

5C±57 POWER±ASSISTED BRAKE SYSTEM
Machining The Drum
If a drum is to be machined, only enough metal should be
removed to obtain a true, smooth braking surface. If a
drum does not clean-up when machined to a maximum
diameter, it must be replaced. Removal of more metal willaffect dissipation of heat and may cause distortion of the
drum.
After refinishing, replace any drum that exceeds a
maximum inside diameter of 296.5 mm (11.673 in). Do
not use a brake drum that is not within the specification.
Maximum inside diameter: 296.5 mm (11.673 in)
Wheel Cylinder Assembly (4y2 Model)
Wheel Cylinder Assembly and Associated Parts
305RW003
Legend
(1) Brake Linings
(2) Wheel Cylinder(3) Bolts
(4) Brake Pipe
Removal
1. Remove brake linings (1).

Refer to
Brake Lining and Associated Parts in this
section.
2. Remove brake pipe (4).

Plug the opening in the line to prevent fluid loss and
contamination.
3. Remove bolts (3) and wheel cylinder (2).
Installation
1. Install wheel cylinder (2) and tighten bolts (3) to the
specified torque.
Torque: 10 N´m (8 lb ft)
2. Install brake pipe (4) and tighten the nut to the
specified torque.
Torque: 16 N´m (12 lb ft)
3. Install brake linings (1).

Refer to
Brake Lining Replacement in this section.

Bleed brake system. Refer to
Hydraulic Brake in
this section.

5C±60
POWER±ASSISTED BRAKE SYSTEM
Main Data and Specifications
General Specifications
Rear drum brake
TypeLeading-trailing, non-servo
Drum inside diameter295 mm (11.6 in)
Wheel cylinder diameter22.22 mm (7/8 in)
Torque Specifications
E05RW010

5C±62
POWER±ASSISTED BRAKE SYSTEM
Brake Pads Inspection 5C±101. . . . . . . . . . . . . . . . .
Brake Pads and Associated Parts 5C±101. . . . . . .
Removal 5C±102. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 5C±102. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rear Disc Brake Rotor (4y4 Model) 5C±104. . . . . . . .
Inspection 5C±104. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Replacing Brake Rotors 5C±104. . . . . . . . . . . . . . . .
Refinishing Brake Rotors 5C±104. . . . . . . . . . . . . . .
Rear Drum (In Disc) Inside Diameter
Check 5C±105. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rear Disc Brake Caliper Assembly
(4y4 Model) 5C±106. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rear Disc Brake Caliper Assembly and
Associated Parts 5C±106. . . . . . . . . . . . . . . . . . . . . .
Removal 5C±106. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 5C±107. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rear Disc Brake Caliper (4y4 Model) 5C±108. . . . . .
Rear Disc Brake Caliper Disassembled
View 5C±108. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Disassembly 5C±109. . . . . . . . . . . . . . . . . . . . . . . . . .
Inspection and Repair 5C±109. . . . . . . . . . . . . . . . . . Reassembly 5C±109. . . . . . . . . . . . . . . . . . . . . . . . . .
Main Data and Specifications
(4y4 Model) 5C±111. . . . . . . . . . . . . . . . . . . . . . . . . .
Brake Lining 5C±112. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Brake Lining and Associated Parts 5C±112. . . . . . .
Removal 5C±112. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Brake Lining Inspection 5C±113. . . . . . . . . . . . . . . .
Installation 5C±113. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Drum Brake Adjustment (4y2 Model) 5C±114. . . . .
Servicing The Brake Drum 5C±114. . . . . . . . . . . . . .
Wheel Cylinder Assembly (4y2 Model) 5C±115. . . . .
Wheel Cylinder Assembly and Associated
Parts 5C±115. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Removal 5C±115. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 5C±115. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Disassembled View 5C±116. . . . . . . . . . . . . . . . . . . .
Disassembly 5C±116. . . . . . . . . . . . . . . . . . . . . . . . . .
Inspection and Repair 5C±116. . . . . . . . . . . . . . . . . .
Reassembly 5C±116. . . . . . . . . . . . . . . . . . . . . . . . . .
Main Data and Specifications 5C±118. . . . . . . . . . . . .
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
330R200002

5C±65 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 contacting 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±68
POWER±ASSISTED BRAKE SYSTEM
Condition CorrectionPossible cause
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±105 POWER±ASSISTED BRAKE SYSTEM
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±112
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
Wheel and Tires 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).

5C±113 POWER±ASSISTED BRAKE SYSTEM
NOTE: Do not over stretch the return spring.
305RS003
9. Remove upper (inner) return spring (9).
10. Remove hold-down spring and cup (3) and hold-down
pin (16).
11. Remove Trailing shoe assembly (7) with parking
brake lever (16).
12. Remove parking brake cable from parking brake lever
(11).
13. Remove retainer (14), wave washer (13), and parking
brake lever (11).
Brake Lining Inspection
Check the shoe assemblies for wear by removing brake
drum.
Replace the shoe assemblies, if lining thickness is less
than 1.0 mm (0.039 in).
The shoe assemblies have a wear indicator that makes a
noise when the linings wear to a degree where
replacement is required.
Minimum limit: 1.0 mm (0.039 in)
305RS001
Installation
1. Apply grease lightly to back place A.
305RW002
Legend
(1) Place A (3 portions for each side)
2. Install parking brake lever (11), wave washer (13),
and retainer (14).
3. Install trailing shoe assembly (7) with parking brake
lever (16).
4. Install the parking brake cable to parking brake lever
(11).
5. Install hold-down pin (16) and hold-down spring and
cup (3).
6. Install upper (inner) return spring (9).
7. Install leading shoe assembly (8) with upper (inner)
return spring (9).
NOTE: Do not over stretch the return spring.
305RS003