Mitsubishi Lancer Evolution IX. Manual - part 488

AC000872

Good

No good

AB

ON-VEHICLE SERVICE

SERVICE BRAKES

35A-7

(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 operation (Refer 
to 

P.35A-7

), 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

M1351009000462

CAUTION

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

P.35A-16

).

CAUTION

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

AC000873AE

A

B

Valve

Spring

Intake manifold
side
(does not hold)

Booster side
(holds)

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

vacuum pump.

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.

BLEEDING

M1351001400552

CAUTION

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

MASTER CYLINDER BLEEDING

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

AC000876

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.

ON-VEHICLE SERVICE

SERVICE BRAKES

35A-8

DISC BRAKE BLEEDING

CAUTION

Take care not to contact the parts or tools to the 
caliper because the paint of caliper will be 
scratched. And if there is brake fluid on the cali-
per, wipe it off quickly.

AC211983

Air bleeder screw

AB

Connect a vinyl tube to the outer end of the air 
bleeder screw to bleed the circuit of air. Then, con-
nect the vinyl tube to the inner end and bleed the cir-
cuit of air. Except for these, the conventional 
procedures shall be followed. After the circuit has 
been bled of air, tighten both air bleeder screws 
securely.

BRAKE LINE BLEEDING

CAUTION

Be sure to filter/strain the brake fluid being 
added to the master cylinder reservoir tank. 
Debris may damage the hydraulic unit.

;

AC211984 AB

4

1

2

3

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

BRAKE FLUID LEVEL SENSOR CHECK

M1351009100447

AC006224AB

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".

FRONT DISC BRAKE PAD CHECK AND 
REPLACEMENT

M1351002300484

NOTE: 

AC000879

When new

When worn

AB

Pad

Wear indicator

Brake
disc

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.

ON-VEHICLE SERVICE

SERVICE BRAKES

35A-9

CAUTION

• Take care not to contact the parts or tools to 

the caliper because the paint of caliper will be 
scratched. And if there is brake fluid on the 
caliper, wipe it off quickly.

• Whenever a pad must be replaced, replace 

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

• If there is a significant difference in the thick-

nesses of the pads on the left and right sides, 
check moving parts.

AC211985

Pads

Pads

AB

Front

Rear

1. Check the brake pad thickness through the caliper 

body check port.

Standard value:

<Front> 10.0 mm
<Rear> 9.0 mm

Minimum limit: 2.0 mm

AC211986

2. When the thickness is less than the limit, always 

replace the pads at an axle set.
(1) Holding the cross spring with one hand, pull 

the pin out of the caliper.

;

AC211987

(2) Remove the pad from the caliper.
(3) To measure brake drag force after new pads 

have been installed, use a spring scale to 
measure the turning sliding resistance of the 
hub with the pads removed.

AC211988

MB990520

AB

(4) Clean the piston and, using special tool piston 

expander (MB990520), push the piston into 
the cylinder.

AC211989 AB

Front

Rear

(5) Apply repair kit grease to the portions of the 

pads indicated. At this time, make sure that 
the grease will not be applied to any other 
surfaces.

(6) Mount the pads to the caliper so that its side 

with the wear indicator is on the outside of the 
vehicle. With the rear pads, ensure that the 
arrow on the pad faces in the same direction 
as the brake disc turns when the vehicle 
moves forward.

AC211990

Pins

Cross
spring

AB

ON-VEHICLE SERVICE

SERVICE BRAKES

35A-10

(7) Holding the cross spring with one hand, fit pins 

in the caliper.

(8) Using a spring scale, measure the turning 

sliding resistance of the hub in the forward 
direction.

(9) Find the brake disc drag force [the difference 

in measurements taken in step(3) and in 
step(8)].

Standard value: 69 N or less

(10)If that drag force exceeds the standard value, 

disassemble the caliper assembly. Then check 
the piston for contamination or rust, and 
confirm if the piston or the piston seal is 
deteriorated.

DISC BRAKE ROTOR CHECK

M1351002900408

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 condi-
tions should be checked.

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.