Buick LeSabre 1965 Service Manual page 559

BRAKES
POWER BRAKES 9 - 3 7
6. After bleeding, bring fluid
level to 1/8" below reservoir lid.
I n s t a l l rubber diaphragm and
master cylinder lid.
NOTE: When pressure bleeding
equipment is not available, do not
use any vacuum assist. The en~
gine should not be running and
the vacuum reserve should be
used up by repeatedly applying
the brake before starting the
bleeding procedure.
9 - 2 1 TESTING OF POWER
BRAKE UNIT
1. Road test the brakes by making
a brake application at about 20
MPH to determine if the vehicle
stops evenly and quickly. If the
pedal has a spongy feel when ap-
plying the brakes, air may be
present in the hydraulic system.
Bleed system as described in
paragraph 9-7.
2. When the engine is stopped and
the transmission is in neutral,
apply brakes several times to
deplete all vacuum reserve in the
system. D e p r e s s brake pedal,
hold light-foot pressure on the
pedal, and start the engine. If the
vacuum system is operating, the
pedal will tend to fall away under
foot pressure, and less pressure
will be required to hold pedal in
applied position. If no action is
felt, the vacuum system is not
functioning.
3. Stop engine. Again deplete all
vacuum reserve in the system.
Depress the brake pedal and hold
foot pressure on the pedal. If the
pedal gradually falls away under
foot pressure, the hydraulic sys-
tem is leaking.
4. If the brake pedal travels to
within one inch of the toeboard,
the brake shoes require adjust-
ment or relining.
5. Start engine. With brakes off,
run to medium speed and turn off
the ignition. Immediately close
the throttle. This builds up vacu-
um. Wait no less than 90 seconds,
then t r y brake action. If not
vacuum-assisted for two or more
applications, vacuum check valve
is faulty or there is a leak in the
vacuum system.