Isuzu Amigo / Axiom / Trooper / Rodeo / VehiCross. Manual - part 191

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:

D

Master cylinder body

D

Fluid reservoir

D

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:

D

Master cylinder body

D

Fluid reservoir

D

O–ring

D

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

D

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

D

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

D

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

D

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

D

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

Type

Dual–circuit

Piston bore diame-
ter

25.4 mm (1.000 in)

Torque Specifications

E05R200005