ISUZU AXIOM 2002 Service Repair Manual

5C±81 POWER±ASSISTED BRAKE SYSTEM
Master Cylinder Assembly
Master Cylinder Assembly and Associated Parts
330R200006
Legend
(1) Electrical Connector
(2) Master Cylinder(3) 2 attaching Nuts
(4) P&B Valve and Bracket
(5) Brake Pipes
Removal
CAUTION: When removing the master cylinder from
the vacuum booster, be sure to get rid of the internal
negative pressure of the vacuum booster (by,
disconnecting the vacuum hose) in advance.
If any negative pressure remains in the vacuum
booster, the piston may possibly come out when the
master cylinder is being removed, letting the brake
fluid run out.
While removing the master cylinder, do not hold the
piston as it can be easily pulled out.
Outside surface of the piston is the surface on which
seals are to slide. Care should be taken to keep the
surface free of cuts and dents.
1. Disconnect electrical connector.
2. Remove brake pipes and after disconnecting the
brake pipe, cap or tape the openings of the brake pipe
to prevent the entry of foreign matter.
3. Remove 2 attaching nuts.
4. Remove P&B valve and bracket.
5. Remove master cylinder.
Inspection
Excessive brake pedal travel, malfunction or dragging
brake suggests that the master cylinder is defective. In
such cases perform the following visual check:
Visual Check
Make parts replacement as required if wear, distortion,
nicks, cuts, corrosion, or other abnormal conditions are
found through the following parts inspection:

Master cylinder body

Fluid reservoir

O±ring

5C±82
POWER±ASSISTED BRAKE SYSTEM
Master Cylinder Assembly
Master Cylinder Assembly Desassembled View
330R200005
Legend
(1) Spring Pin
(2) Reserve Tank and Reserve Tank Cap
(3) O±ring(4) Primary Piston Assembly
(5) Secondary Piston Assembly
(6) Cylinder Body
Desassembly
1. Remove the spring pin.
2. Remove the reserve tank and the reserve tank cap.
The brake fulid level switch is built±in to the reserve tank
and cannot be removed.
3. Remove the O±ring.
4. Remove the snap ring.
5. Remove the primary piston assembly.
6. Invert the cylinder body and push on the secondary
piston until the pin falls free.7. Remove the secondary piston assembly.
8. Remove the cylinder body.
Inspection
Excessive brake pedal travel, malfunction or dragging
brake suggests that the master cylinder is defective. In
such cases perform the following visual check:

5C±83 POWER±ASSISTED BRAKE SYSTEM
Visual Check
Make parts replacement as required if wear, distortion,
nicks, cuts, corrosion, or other abnormal conditions are
found through the following parts inspection:

Master cylinder body

Fluid reservoir

O±ring

Wash each part in brake fluid before beginning the
inspection procedure.

Check the inside surfaces of the master cylinder for
abrasion, corrosion, and other damage. Replace the
cylinder if necessary.

Check the return port for clogging. Clean the port with
a wire and compressed air if nesessay.

Check the piston and piston cup for abrasion,
damage, and wear. Replace the piston assembly if
any of these conditions exist.

Check the return spring. Replace the spring if it is
weak.

Check the snap ring. Replace the snap ring if it is
stretched or weak.
Reassembly
1. Wash each master cylinder internal part in brake fluid
before beginning installation.
2. Install the cylinder body.
3. Press the secondary piston assembly into the
cylinder body and hold it. Thread the pin through the
long hole of the piston to secure the piston assembly.
4. Install the primary piston assembly.
5. Install the snap ring.
6. Install the O±ring
7. Install the reserve tank and the reserve tank cap.
8. Install the spring pin.
Installation
1. Install master cylinder.
When replacing the master cylinder or vacuum
booster or both, always measure the vacuum booster
push rod protrusion and adjust it as necessary (Refer
to
Vacuum Booster in section).
2. Install P&B valve and bracket.
3. Install 2 attaching nuts and tighten the attaching nuts
to the specified torque.
Torque: 13 N´m (113 lb in)
4. Install brake pipes and tighten the brake pipe to the
specified torque.
Master cylinder and P&B valve sides
Torque: 12 N´m (104 lb in)
Others
Torque: 16 N´m (12 lb in)
5. Connect electrical connector.

5C±84
POWER±ASSISTED BRAKE SYSTEM
Main Data and Specifications
General Specifications
TypeDual±circuit
Piston bore diame-
ter25.4 mm (1.000 in)
Torque Specifications
E05R200005

5C±85 POWER±ASSISTED BRAKE SYSTEM
Vacuum Booster Assembly
Vacuum Booster Assembly and Associated Parts
331R200004
Legend
(1) Snap Pin
(2) Vacuum Booster Fixing Nut
(3) Vacuum Hose(4) Master Cylinder
(5) Vacuum Booster
(6) Pin
Removal
1. Before removing the vacuum booster assembly,
disconnect and remove the brake pipes.
2. Remove master cylinder, refer to
Master Cylinder
Removal
in this section.
CAUTION: When removing the master cylinder from
the vacuum booster, be sure to get rid of the internal
negative pressure of the vacuum booster (by,
disconnecting the vacuum hose) in advance.
If any negative pressure remains in the vacuum
booster, the piston may possibly come out when the
master cylinder is being removed, letting the brake
fluid run out.
Do not hold the piston while removing the master cy-
liner, the piston can be easily pulled out.
Outside surface of the piston is the surface on which
seals are to slide. Care should be taken to keep the
surface free of cuts and dents.
3. Remove vacuum hose.
4. Disconnect the yoke clevis from the brake pedal.5. Remove vacuum booster fixing nut.
6. Remove vacuum booster.

5C±86
POWER±ASSISTED BRAKE SYSTEM
Inspection and Repair
Vacuum Hose (The built in check valve)
1. Inspect the check valve (2), which is installed inside
the vacuum hose.
2. Air should pass freely from the vacuum booster (3) to
the engine (1).
3. Air should not pass from the engine (1) to the vacuum
booster (3). If it does, the check valve is inoperative
and the vacuum hose built in the check valve must be
replaced.
HEC ENGINE
360RW001
6VD1 ENGINE
360RY00004

5C±87 POWER±ASSISTED BRAKE SYSTEM
Exterior Components
Exterior Components and Associated Parts
331R200006
Legend
(1) 2 Gaskets and Spacer
(2) Vacuum Booster(3) Plate and Seal Assembly
(4) Retainer
(5) Master Cylinder
Removal
1. Remove master cylinder. Refer to Master Cylinder in
this section.
2. Remove vacuum booster. Refer to
Vacuum Booster
in this section.
3. Remove 2 gaskets and spacer.
4. Remove retainer, plate and seal assembly.
331RS003

5C±88
POWER±ASSISTED BRAKE SYSTEM
Inspection and Repair
Visual Check
Make necessary parts replacement if cuts, nicks,
excessive wear, or other abnormal conditions are found
through inspection.
NOTE: The parts listed below must be replaced with new
ones whenever the master cylinder is removed.
1. Plate and seal assembly
2. Retainer
Installation
1. Install plate and seal assembly.
2. Install retainer.
3. Install vacuum booster, refer to
Vacuum Booster in
this section.
4. Install master cylinder, refer to
Master Cylinder in this
section and after installation, perform brake pedal
check and adjustment. Refer to
Brake Pedal in this
section.
Vacuum Booster Overhaul
Vacuum Booster
The vacuum booster cannot be disassembled for repair.
Replace a defective vacuum booster with a new one.

5C±89 POWER±ASSISTED BRAKE SYSTEM
Main Data and Specifications
General Specifications
Vacuum booster diaphragm diameter (Front)205 mm (8.07 in)
Vacuum booster diaphragm diameter (Rear)230 mm (9.06 in)
Push rod strokeMore than 32.0 mm (1.26 in)
Plunger diameter10.25 mm (0.40 in)
Push rod diameter27.4 mm (1.08 in)
Torque Specifications
E05R200004

5C±90
POWER±ASSISTED BRAKE SYSTEM
Front Disc Brake Pads
Front Disc Brake Pads Inspection
Check the outer pad by looking at each caliper from
above. Check the thickness on the inner pad by looking
down through the inspection hole in the top of the caliper.
Whenever the pad is worn to about the thickness of the
pad base, the pad should be removed for further
measurements. The pad should be replaced anytime the
pad thickness (1) is worn to within 1.00 mm (0.039 in) of
the pad itself.
Wear indicators are installed on disc brake pads, disc
brake pads need replacement when the wear indicator is
heard.
Minimum limit (1): 1.0 mm (0.039 in)
302RS002
Front Disc Brake Pads and Associated Parts
302R200026
Legend
(1) Pin Bolt
(2) Caliper Assembly(3) Pad Assembly
(4) Clip
(5) Outer Side