Subaru 2002 IMPREZA Service Manual page 2330

BRAKE
2. OPERATION CHECK (WITH GAUGES)
CAUTION:
When checking operation, be sure to securely
apply the hand brake.
• Checking with gauges
Connect gauges as shown in the figure. After
bleeding air from pressure gauges, proceed to
each check.
(1) Pressure gauge
(2) Vacuum gauge
(3) Adapter hose
(4) Vacuum hose
(5) Pedal force gauge
• Air tightness check
1) Start the engine and keep it running until a vac-
uum of 66.7 kPa (500 mmHg, 19.69 inHg) = point A
is indicated on vacuum gauge. Do not depress the
brake pedal.
(1) Pressure gauge
(2) Vacuum gauge
BRAKE BOOSTER
2) Stop the engine and watch the gauge. If the vac-
uum drop range is less than 3.3 kPa (25 mmHg,
0.98 inHg) within 15 seconds after stopping engine,
the brake booster is functioning properly.
If defective, the cause may be one of those listed
below.
• Check valve malfunction
• Leak from vacuum hose
• Leak from the shell jointed portion or stud bolt
welded portion
• Damaged diaphragm
• Leak from valve body seal and bearing portion
• Leak from plate and seal assembly portion
• Leak from poppet valve assembly portion
• Loaded air tightness check
1) Start the engine and depress brake pedal with
pedal force of 196 N (20 kgf, 44 lb). Keep the en-
gine running until a vacuum of 66.7 kPa (500
mmHg, 19.69 inHg) = point B is indicated on vacu-
S4M0467A
um gauge while the pedal is still depressed.
S4M0468A
BR-52
(1) Pressure gauge
(2) Vacuum gauge
(3) Pedal force gauge
(4) Depress
S4M0469A