Subaru 2002 IMPREZA Service Manual page 2329

C: INSPECTION
1. OPERATION CHECK (WITHOUT GAUG-
ES)
CAUTION:
When checking operation, be sure to securely
apply the hand brake.
• Checking without gauges
This method cannot determine the exact portion
which has failed, but it can provide a rough under-
standing of the nature of failure if checking is con-
ducted in accordance
procedures.
• Air tightness check
Start the engine, and run it for 1 to 2 minutes, then
turn it off. Depress the brake pedal several times
applying same pedal force as that used in ordinary
braking operations. The pedal stroke should be
greatest on 1st depression, and it should become
smaller with each successive depression. If no
change occurs in the pedal height while in a de-
pressed state, the brake booster is faulty.
(1) OK
(2) NOT OK
(3) 1st
(4) 2nd
(5) 3rd
NOTE:
• In the event of defective operation, inspect the
condition of check valve and vacuum hose.
• Replace them if faulty and conduct the test
again.
• If no improvement is observed, check precisely
with gauges.
BRAKE BOOSTER
with the following
S4M0465A
BR-51
• Operation check
1) With the engine off, depress the brake pedal
several times applying same pedal force and make
sure that pedal height does not vary with each de-
pression of pedal.
(1) When engine is stopped
(2) When engine is started
2) With the brake pedal depressed, start the en-
gine.
3) As the engine starts, the brake pedal should
move slightly toward the floor. If no change occurs
in the pedal height, the brake booster is faulty.
NOTE:
If faulty, check precisely with gauges.
• Loaded air tightness check
Depress the brake pedal while engine is running,
and turn off the engine while pedal is still de-
pressed. Keep the pedal depressed for 30 sec-
onds; if no change occurs in the pedal height, the
brake booster is functioning normally; if the pedal
height increases, it is faulty.
NOTE:
If faulty, check precisely with gauges.
BRAKE
S4M0466A