Cadillac 60 Series 1963 Shop Manual page 188

BRAKES
8-23
are not functioning or shoes require relining. If
pedal has a spongy* feel, air may be present in
hydraulic system. Bleed system as described
in Note 9.
3. With brakes off, operate engine at medium
speed, then back to idle and turn off ignition. Wait
at least two minutes, then try brake action. If not
vacuum assisted for two or more applications,
vacuum check valve is faulty or there is a leak
in vacuum system.
4. With vacuum depleted from system, depress
brake pedal, hold light foot pressure on pedal,
and start engine. If vacuum system is operating,
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, vacuum
system is not functioning.
5. Road test brakes by making a brake applica-
tion at various speeds up to 50 mph to determine
if car stops evenly and effectively.
DIAGNOSIS CHART
CONDITION
Brake pedal goes down to toe-
board or drops off about half
the distance from its normal
position.
CAUSE
Uneven wear on linings.
No fluid in reservoir.
Leaking front or rear brake
line.
Air in brake system which
causes a rubbery action of
brake pedal.
Wheel cylinder piston cups
swollen by mineral oil in sys-
tem, or sub-standard brake
fluid.
Leaking master cylinder piston
cups.
Disconnected unit linkage.
Cracked master cylinder cast-
ing.
Adjusters sticky.
Brake shoes improperly ad-
justed.
Leak at master c}4inder head-
nut.
CORRECTION
Replace shoe and linings.
Add fluid, inspect for leakage,
and bleed system.
Tighten or replace.
B l e e d s y s t e m . Check for
shrunken or swollen wheel cyl-
inder piston cups, and if noted
replace and correct cause.
Check residual check valves
and replace if faulty.
D i s a s s e m b l e all hydraulic
parts and wash with alcohol.
Dry with compressed air be-
fore assembly to keep alcohol
out of system.
Replace all rubber parts in
system, including hoses.
Replace brake shoe assemblies
or linings if glazed by brake
fluid leakage.
Refill with heavy duty brake
fluid and bleed system.
Replace.
Connect.
Replace.
Lubricate.
Check automatic adjusters and
make necessary adjustments.
Install new copper gasket and
torque headnut to 105 foot-
pounds.