Subaru SVX 1992 Manual page 885

BRAKES [W7Do] 4-4
6. AIR TIGHTNESS CHECK
1) Start engine and keep it running until a vacuum of
66 .7 kPa (500 mmHg, 19 .69 inHg) is indicated on vac-
uum gauge. Do not depress brake pedal .
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 stopping engine, 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 ASSY portion
" Leak from poppet valve ASSY portion
7. LOADED AIR TIGHTNESS CHECK
1) Start engine and depress brake pedal with pedal
force of 196 N (20 kg, 44 lb). Keep engine running until
a vacuum of 66 .7 kPa (500 mmHg, 19 .69 inHg) is
indicated on vacuum gauge while the pedal is still
depressed.
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 stopping engine,
brake booster is functioning properly .
If defective, refer to "Air tightness check" described
above.
8. LACK OF BOOSTING ACTION CHECK
Turn off engine, and set the vacuum gauge reading at
"0". Then, check the fluid pressure when brake pedal is
depressed . The pressure must be greater than the
standard value listed below .
Brake pedal force All model
147N (15 kg, 33 lb) 490 kPa (5 kg/cMZ, 71 psi)
294N (30kg, 66 lb) 1,569 kPa (16 kg/cmz, 228 psi)
9. BOOSTING ACTION CHECK
Set the vacuum gauge reading at 66.7 kPa (500 mmHg,
19.69 inHg) by running engine . Then, check the fluid
pressure when brake pedal is depressed . The pressure
must be greater than the standard value listed below .
Brake pedal force All model
147N (15 kg, 33 lb) 4,511 kPa (46 kg/cm2, 654 psi)
294N (30kg, 66 lb) 9,513 kPa (97 kg/cMZ, 1,379 psi)
D: HANDLING PRECAUTIONS
1) After protector has been removed from push-rod, do
not turn the master cylinder side of brake booster
downwards.
(1) If the master cylinder side is turned downwards,
push-rod may come loose by virtue of its own weight,
and reaction disc may drop into brake booster.
(2) Whether or not reaction disc has dropped can be
determined by measuring the dimension "L".
The projected amount "L" of pushrod should be as
follows :
Fig. 120
Push rod projection
(3) If protector is fitted correctly, reaction disc will
not fall out. be discarded if it has been dropped .
3) Use special care when handling operating rod.
If excessive force is applied to operating rod, sufficient
to cause a change in the angle in excess of ± 3°, it may
result in damage to the power piston cylinder.
4) Use care when placing brake booster on the floor .
Force /~
If external force is applied from
above when brake booster is
placed in this position, the resin
portion as indicated by "P", may
be damaged.
OP
84-408
Fig. 121 Handling
55