Subaru Legacy 2002 Service Manual page 2177

Brake
2. OPERATION CHECK (WITH GAUGES)
S405166A1002
CAUTION:
When checking operation, be sure to securely
apply the hand brake.
¼ Checking with gauges
Connect gauges as shown in Figure. After bleed-
ing air from pressure gauges, proceed to each
check.
(1) Pressure gauge
(2) Vacuum gauge
(3) Adapter hose
(4) Vacuum hose
(5) Pedal force gauge
¼ Air tightness check
1) Start engine and keep it running until a vacuum
of 66.7 kPa (500 mmHg, 19.69 inHg) = point A is
indicated on vacuum gauge. Do not depress brake
pedal.
(1) Pressure gauge
(2) Vacuum gauge
BRAKE BOOSTER
2) Stop engine and watch the gauge. If the
vacuum drop range is less than 3.3 kPa (25
mmHg, 0.98 inHg) within 15 seconds after stop-
ping engine, brake booster is functioning properly.
If defective, the cause may be one of those listed
below.
¼ Check valve malfunction
¼ Leak from vacuum hose
¼ Leak from the shell jointed portion or stud bolt
welded portion
¼ Damaged diaphragm
¼ Leak from valve body seal and bearing portion
¼ Leak from plate and seal assembly portion
¼ Leak from poppet valve assembly portion
¼ Loaded air tightness check
1) Start engine and depress brake pedal with
pedal force of 196 N (20 kgf, 44 lb). Keep engine
running until a vacuum of 66.7 kPa (500 mmHg,
19.69 inHg) = point B is indicated on vacuum
gauge while the pedal is still depressed.
S4M0467A
(1)
(2)
(3)
(4)
2) Stop engine and watch vacuum gauge.
If the vacuum drop range is less than 3.3 kPa (25
mmHg, 0.98 inHg) within 15 seconds after stop-
ping engine, brake booster is functioning properly.
If defective, refer to "AIR TIGHTNESS CHECK".
<Ref. to BR-37, INSPECTION, Brake Booster.>
S4M0468A
BR-38
Pressure gauge
Vacuum gauge
Pedal force gauge
Depress
S4M0469A