Mitsubishi Montero (2004+). Manual — part 1001

GENERAL DESCRIPTION

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BASIC BRAKE SYSTEM

35A-3

GENERAL DESCRIPTION

M1351000100235

The brake system has been designed to give greater
reliability and durability and to provide excellent brak-
ing performance.

FEATURES

Improved Braking Performance

• Adoption of a hydraulic brake booster (HBB)

which maintains a high brake-assisting force
even in high deceleration ranges.

• 16-inch ventilated disc brakes have been

adopted to provide stable braking force and
improved braking feel.

Improved Stability

• Adoption of an electronic brake-force distribution

(EBD) which makes it possible to maintain the
maximum amount of braking force even when the
vehicle's load is unevenly distributed.

• Adoption of independent front and rear wheel

brake lines (H piping).

• Ventilated discs have been adopted for front

wheel and rear wheel in order to improve
anti-fading performance.

Improved Serviceability

• A diagnosis function has been adopted for the

HBB system in order to make inspection easier.

• For the front and rear disc brakes, an outer disc

method separated hub and rotor has been
adopted to make removal and installation easier.

• The HBB reservoir tank cap has been colored

white to make identification easier.

CONFIGURATION DIAGRAM

AC206001AC

HYDRAULIC BRAKE
BOOSTER (HBB)

FRONT DISC BRAKE

PARKING BRAKE

REAR DISC BRAKE

GENERAL DESCRIPTION

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BASIC BRAKE SYSTEM

35A-4

HYDRAULIC BRAKE BOOSTER (HBB)

The master cylinder hydraulic pressure for the front
brakes is assisted by a brake booster which utilizes
accumulator pressure; the hydraulic pressure gener-
ated by the accumulator is introduced directly to the
rear brakes.

AC000675

ACCUMULATOR

CHECK VALVE

PUMP
MOTOR

PRESSURE
SWITCH

RELIEF VALVE

RESERVOIR (BUILT-IN BRAKE
FLUID LEVEL WARNING SWITCH)

MASTER CYLINDER PISTON

BOOSTER
CHAMBER

POWER PISTON

REACTION DISC

OPERATING ROD

MASTER CYLINDER AND
BRAKE BOOSTER

SELECT SOLENOID VALVE

CONTROL SOLENOID VALVE

REACTION
ROD

SPOOL
VALVE

REGULATOR PISTON

HYDRAULIC UNIT

IN IN IN IN

OUT OUT OUT OUT

REAR-LEFT

REAR-RIGHT

FRONT-LEFT

FRONT-RIGHT

GENERAL DESCRIPTION

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BASIC BRAKE SYSTEM

35A-5

HYDRAULIC BRAKE BOOSTER (HBB)
OPERATION

1. When the pedal operating force is transmitted in

turn by the operating rod, the power piston and
the master cylinder piston, the regulator piston
and the spool valve move to the left.

2. When the spool valve opens line A and closes line

B, the accumulator pressure is supplied to the
rear brakes. This pressure is introduced to the
booster chamber and provides power assistance
to move the master cylinder piston to the left.

3. Then, when the pressure in the booster chamber

increases, the pressure which is applied to the
rear (left side) of the reaction disc also increases,
and the reaction disc starts to change shape. The
reaction disc contacts the reaction rod, and the
reaction rod in turn contacts the spool valve, so
that the master cylinder pressure being applied
towards the left and the booster pressure being
applied to the right are brought into balance by the
reaction disc. This allows the power-assist
hydraulic pressure generated by the pedal
operating force to be kept at an equilibrium.

<When booster is not operating>

<When booster is operating>

AC000676

AC000676 AB

ACCUMULATOR

RESERVOIR

CHECK
VALVE

PUMP
MOTOR

PRESSURE
SWITCH

LINE B (OPEN)

LINE A (CLOSED)

RETURN SPRING

REACTION DISC

REACTION ROD

SPOOL
VALVE

REAR

FRONT

REGULATOR PISTON

MASTER CYLINDER RETURN SPRING

MASTER CYLINDER PISTON

POWER PISTON

BOOSTER CHAMBER

OPERATING ROD

MASTER CYLINDER
MECHANISM

AC000677AB

ACCUMULATOR
PRESSURE

LINE B
(CLOSED)

LINE A
(OPEN)

SPOOL
VALVE

ASSIST
FORCE

BOOSTER
CHAMBER

OPERATING ROD

REACTION ROD

REACTION
DISC

REAR

FRONT

POWER PISTON

BASIC BRAKE SYSTEM DIAGNOSIS

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BASIC BRAKE SYSTEM

35A-6

<When a loss of accumulator pressure occurs>
If a loss of accumulator pressure occurs because of
a problem such as a pump motor problem, the power
assist force and rear brake pressure cannot increase
in response to the input from the brake pedal.
Accordingly, the front brakes can be operated
directly by depressing the brake pedal, but the rear
brakes do not operate at all.

BASIC BRAKE SYSTEM DIAGNOSIS

INTRODUCTION

M1351009700223

The hydraulic brake system consists of the brake
pedal, the hydraulic brake booster (HBB), and the
disc brakes. Insufficient braking power or noise may
occur due to wear, damage or incorrect adjustment
of these parts.

DIAGNOSTIC TROUBLESHOOTING STRATEGY

M1351009800220

Use these steps to plan your diagnostic strategy. If
you follow them carefully, you will be sure that you
have exhausted most of the possible ways to find a
basic brake system fault.
1. Gather information from the customer.

2. Verify that the condition described by the

customer exists.

3. Find the malfunction by following the symptom

chart.

4. Verify malfunction is eliminated.

SYMPTOM CHART

M1351009900238

SYMPTOM PROCEDURES

INSPECTION PROCEDURE 1: Vehicle Pulls to One Side when Brakes are Applied

DIAGNOSIS

STEP 1. Check for oil, water, etc., on the pad
contact surface of all brakes.

Q: Is oil, water, etc., on the pad contact surface?