Isuzu Amigo / Axiom / Trooper / Rodeo / VehiCross. Manual - part 1189

POWER-ASSISTED BRAKE SYSTEM

5C–23

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–24

POWER-ASSISTED BRAKE SYSTEM

Main Data and Specifications

General Specifications

Torque Specifications

E05R200005

Type

Dual–circuit

Piston bore 
diameter

25.4 mm (1.000 in)

POWER-ASSISTED BRAKE SYSTEM

5C–25

Vacuum Booster Assembly

Vacuum Booster Assembly and
Associated Parts

331R200004

EndOFCallout

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
cyliner, 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.

Legend

(1) Pin
(2) Vacuum Booster Fixing Nut
(3) Vacuum Hose

(4) Master Cylinder
(5) Vacuum Booster
(6) Snap Pin

5C–26

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