ON-VEHICLE SERVICE
BASIC BRAKE SYSTEM35A-15
(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-15), vacuum hose for leaks, high volume engine
vacuum applied to booster. Repair or replace as necessary.
If these are OK, replace booster and repeat this test starting
at Step 1.
CHECK VALVE OPERATION CHECKM1351009000376
The check valve should not be removed from the vacuum
hose.
1. Remove the vacuum hose. (Refer to P.35A-26).
If the check valve is defective, replace it as an assembly
together with the vacuum hose.
2. Check the operation of the check valve by using a vacuum
pump.
VACUUM PUMP
CONNECTIONCRITERIA
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.
ON-VEHICLE SERVICE
BASIC BRAKE SYSTEM35A-20
.
BRAKE DISC THICKNESS CHECK
1. Using a micrometer, measure disc thickness at eight
positions, approximately 45 degrees apart and 10 mm (0.4
inch) in from the outer edge of the disc.
FRONT BRAKE DISC
Standard value: 26.0 mm (1.02 inches)
Minimum limit: 24.4 mm (0.96 inch)
REAR BRAKE DISC
Standard value: 10.0 mm (0.39 inch)
Minimum limit: 8.4 mm (0.33 inch)
NOTE: Thickness variation (at least 8 positions) should not
be more than 0.015 mm (0.0006 inch). 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.
