Mitsubishi Grandis. Manual — part 891

ON-VEHICLE SERVICE

BASIC BRAKE SYSTEM

35A-6

(1) Run the engine for one or two minutes, and

then stop it. If the pedal depresses fully the
first time but gradually becomes higher when
depressed succeeding times, the booster is
operating properly. If the pedal height remains
unchanged, the booster is defective. Go to
step 2.

(2) With the engine stopped, step on the brake

pedal several times. Then step on the brake
pedal and start the engine. If the pedal moves
downward slightly, the booster is in good
condition. If there is no change, the booster is
defective. Go to step 3.

(3) With the engine running, step on the brake

pedal and then stop the engine. Hold the
pedal depressed for 30 seconds. If the pedal
height does not change, the booster is in good
condition, if the pedal rises, the booster is
defective.

2. If the above three tests are okay, the booster is

OK. If one of the above three tests is not okay, the
check valve, vacuum hose, or booster is
defective. Check the check valve (Refer to

P.35A-6

), vacuum hose for leaks, high volume

engine vacuum applied to booster. Repair or
replace as necessary. If these are OK, replace the
booster and repeat this test starting at Step 1.

CHECK VALVE OPERATION CHECK

M1351009000451

CAUTION

The check valve should not be removed from the
vacuum hose.
1. Remove the vacuum hose (Refer to

P.35A-14

).

CAUTION

If the check valve is defective, replace it as an
assembly unit together with the vacuum hose.

2. Check the operation of the check valve by using a

vacuum pump.

BLEEDING

M1351001400563

CAUTION

Use only brake fluid DOT 3 or DOT 4. Never mix
the specified brake fluid with other fluid as it will
influence the braking performance significantly.

MASTER CYLINDER BLEEDING

The master cylinder used has no check valve, so if
bleeding is carried out by the following procedure,
bleeding of air from the brake pipeline will become
easier (When brake fluid is not contained in the
master cylinder).
1. Fill the reservoir with brake fluid.
2. Keep the brake pedal depressed.

AC000871AE

When engine
is stopped

When engine
is started

AC000872

Good

No good

AE

Vacuum pump
connection

Accept/reject criteria

Connection at the brake
booster side (A)

A negative pressure
(vacuum) is created and
held.

Connection at the intake
manifold side (B)

A negative pressure
(vacuum) is not created.

AC000873AE

A

B

Valve

Spring

Intake manifold
side
(does not hold)

Booster side
(holds)

ON-VEHICLE SERVICE

BASIC BRAKE SYSTEM

35A-7

3. Have another person cover the master cylinder

outlet with a finger.

4. With the outlet still closed, release the brake

pedal.

5. Repeat steps 2

− 4 three or four times to fill the

inside of the master cylinder with brake fluid.

BRAKE LINE BLEEDING

Start the engine and bleed the air in the sequence
shown in the figure.

BRAKE FLUID LEVEL SENSOR CHECK

M1351009100458

The brake fluid level sensor is in good condition if
there is no continuity when the float surface is above
"MIN" and if there is continuity when the float surface
is below "MIN".

DISC BRAKE PAD CHECK AND
REPLACEMENT

M1351002300495

NOTE:

The brake pads have indicators that contact the
brake disc when the brake pad thickness becomes 2
mm, and emit a squealing sound to warn the driver.

CAUTION

• Whenever a pad must be replaced, replace

both LH and RH wheel pads as a set to
prevent the vehicle from pulling to one side
when braking.

• If there is a significant difference in the

thicknesses of the pads on the left and right
sides, check the sliding condition of the
piston and slide pins.

1. Check the brake pad thickness through the caliper

body check port.

Standard value: 10.0 mm
Minimum limit: 2.0 mm

AC302063

AC

Master cylinder

AC301228AB

4

2

1

3

AC311385 AB

AC000879

When new

When worn

AD

Pad

Wear indicator

Brake
disc

AC311390 AB

<Front>

<Rear>

ON-VEHICLE SERVICE

BASIC BRAKE SYSTEM

35A-8

CAUTION

Do not wipe off the special grease that is on the
lock pin or allow it to contaminate the lock pin.

2. Remove the guide/lock pin bolt. Pivot the caliper

assembly and hold it with wires.

3. Remove the following parts from caliper support.

(1) Shim
(2) Pad assembly or Pad and wear indicator

assembly

(3) Pad clip

4. In order to measure the brake drag force after pad

installation, measure the rotary-sliding resistance
of the hub with the pads removed. For the front
brakes, refer to

P.35A-18

. For the rear brakes,

refer to

P.35A-23

.

5. Install the pads and caliper assembly, and then

check the brake drag force. For the front brakes,
refer to

P.35A-18

. For the rear brakes, refer to

P.35A-23

.

DISC BRAKE ROTOR CHECK

M1351002900419

CAUTION

Disc brakes must be kept within the allowable
service values in order to maintain normal brake
operation.
Before turning the brake disc, the following
conditions should be checked.

AC311391AB

<Front>

<Rear>

Guide pin

Lock pin

AC313232 AB

2

1

2

3

2

1

1

1

<Front>

<Rear>

3

3

2

ON-VEHICLE SERVICE

BASIC BRAKE SYSTEM

35A-9

BRAKE DISC THICKNESS CHECK

1. Using a micrometer, measure disc thickness at

eight positions, approximately 45

° apart and 10

mm in from the outer edge of the disc.
Standard value:

<Front> 26.0 mm
<Rear> 10.0 mm

Minimum limit:

<Front> 24.4 mm
<Rear> 8.4 mm

NOTE: Thickness variation (at least 8 positions)
should not be more than 0.015 mm.

Inspection item

Remark

Scratches, rust, saturated lining materials and wear

• If the vehicle is not driven for a long period of

time, sections of the discs that are not in contact
with the pads will become rusty, causing noise
and shuddering.

• If grooves and scratches resulting from excessive

disc wear are not removed prior to installing a new
pad assembly, there will be inadequate contact
between the disc and the lining (pad) until the
pads conform to the disc.

Run-out

Excessive run-out of the discs will increase the pedal
depression resistance due to piston kick-back.

Change in thickness (parallelism)

If the thickness of the disc changes, this will cause
pedal pulsation, shuddering and surging.

Inset or warping (flatness)

Overheating and improper handling while servicing
will cause warping or distortion.

ACX00668