Subaru 2001 IMPREZA Service Manual page 58

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 the failure if checking is
conducted in accordance with the following proce-
dures.
• Air tightness check
Start engine, and run it for 1 to 2 minutes, then turn
it off. Depress brake pedal several times applying
the same pedal force as that used in ordinary brak-
ing operations. The pedal stroke should be greatest
on the 1st depression, and it should become small-
er with each successive depression. If no change
occurs in the pedal height while in a depressed
state, 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 the 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
• Operation check
1) With engine off, depress brake pedal several
times applying the same pedal force and make
sure that the pedal height does not vary with each
depression of the pedal.
2) With brake pedal depressed, start engine.
3) As engine starts, brake pedal should move
slightly toward the floor. If no change occurs in the
pedal height, brake booster is faulty.
NOTE:
If faulty, check precisely with gauges.
• Loaded air tightness check
Depress brake pedal while engine is running, and
turn off engine while the pedal is still depressed.
Keep the pedal depressed for 30 seconds; if no
change occurs in the pedal height, brake booster is
functioning normally; if the pedal height increases,
it is faulty.
S4M0465A
NOTE:
If faulty, check precisely with gauges.
BR-57
(1) When engine is stopped
(2) When engine is started
BRAKE
S4M0466A