ISUZU AXIOM 2002 Service Repair Manual

5C±51 POWER±ASSISTED BRAKE SYSTEM
Disassembly
1. Remove guide bolt.
2. Remove lock bolt.
3. Remove dust boot; guide bolt and lock bolt.
4. Remove dust boot ring, using a small screwdriver.
302RS016
5. Insert a block of wood into the caliper and force out
the piston by blowing compressed air into the caliper
at the flexible hose attachment. This procedure must
be done prior to removal of the dust boot.
Remove piston.
WARNING: D O N O T P L A C E Y O U R F I N G E R S I N
FRONT OF THE PISTON IN AN ATTEMPT TO CATCH
OR PROTECT IT WHEN APPLYING COMPRESSED
AIR. THIS COULD RESULT IN PERSONAL INJURY.
CAUTION: Use just enough air to ease the piston
out of the bore. If the piston is blown out, it may be
damaged.
302RS017
6. Remove dust boot: piston.
7. Remove piston seal.
8. Remove bleeder with cap.
9. Remove caliper body.
Inspection and Repair
Make necessary parts replacement, if wear, damage,
corrosion or any other abnormal conditions are found
through inspection.
Check the following parts:

Rotor

Cylinder body

Cylinder bore

Piston

Guide bolt, lock bolt

Support bracket
NOTE: The piston dust seal and dust boot are to be
replaced each time the caliper is overhauled. Discard
these used rubber parts and replace with new ones.
Reassembly
1. Install caliper body.
2. Install bleeder with cap and tighten the cap to the
specified torque.
Torque: 8 N´m (69 lb ft)
3. Install piston seal and apply special rubber grease to
the piston seal and cylinder wall, then insert the piston
seal into the cylinder. The special rubber grease is
included in the repair kit.
302RS018
4. When inserting the piston into the cylinder, use finger
pressure only and do not use a mallet or other impact
tool, since damage to the cylinder wall or piston seal
can result.
Install piston.

5C±52
POWER±ASSISTED BRAKE SYSTEM
302RS019
5. Apply special grease (approximately 1g) to the piston
and attach the dust boot to the piston and caliper.
Insert the dust boot ring into the dust boot.
302RS020
6. Install guide bolt and lock bolt dust boot.
7. Install the dust boot on the support bracket after
applying special grease (Approx. 1g) onto the dust
boot inner surface. Also apply special grease onto
the lock bolt and guide bolt setting hole of the support
bracket.
302RS021
8. Install lock bolt and guide bolt and tighten the bolt to
the specified torque.
Torque: 44 N´m (32 lb ft)

5C±53 POWER±ASSISTED BRAKE SYSTEM
Main Data and Specifications (4y4 Model)
General Specifications
TypeFloating, pin slide
Pad dimension33 cm
(5.11 in
)
Adjusting methodSelf±adjusting
Piston diameter41.3 mm (1.63 in)
Disc typeVentilated
Disc thickness18 mm (0.71 in)
Disc effective diameter269.2 mm (10.60 in)
Torque Specifications
E05RW005

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).

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±58
POWER±ASSISTED BRAKE SYSTEM
Disassembled View
305RS006
Legend
(1) Boot
(2) Piston Assembly
(3) Piston Cup
(4) Return Spring
(5) Bleeder
(6) Wheel Cylinder
Disassembly
1. Remove boot (1) and piston assembly (2).
2. Remove piston cup (3) from piston assembly (2).
3. Remove return spring (4) and bleeder (5) from wheel
cylinder (6).
Inspection and Repair
1. Make necessary parts replacement if wear, damage,
corrosion or any other abnormal condition are found
through inspection.
Check the following parts;

Wheel cylinder body

Cylinder bore

Piston

Return spring

BleederNOTE: Replace the piston cups and boots each time the
wheel cylinder is overhauled. Discard these used rubber
parts and replace with new ones.
Reassembly
1. Lubricate the cylinder bore with clean rubber grease.
305RS007
2. Install bleeder (5) to wheel cylinder (6).
Torque: 10 N´m (8 lb ft)
305RS008

5C±59 POWER±ASSISTED BRAKE SYSTEM
3. Install new piston cups (3) on each piston so that the
flared end of the cups are turned to the inboard side of
the pistons.
Attach the return spring (4) and the boot (1) to the
piston.
305RS009
4. Apply DELCO silicone lube No. 5459912 (or
equivalent) to the piston and the inner face of the
boots.
5. Install piston assembly (2) to wheel cylinder (6).

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