Buick LeSabre 1965 Service Manual page 554

9 - 3 2 POWER BRAKES
BRAKES
Figure 9-27—Removing Power Piston
Snap Ring
6. Remove the rolling diaphragm
from the support plate and lay
both parts aside.
7. Remove the silencer from the
neck of the power piston tube.
8. Position the power piston in a
vise padded with shop towels, with
the tube down (Do Not Clamp on
Tube). The outside surface of the
tube acts as a bearing surface.)
9. Use Truarc Pliers #2, or KM
J-4880, to remove the snap ring
on the air valve. See Figure 9-27.
10. Set up J-6180-01 Power Ram
and J-6207 Hydraulic Pump with
J-8609 Press Plate. Insert power
piston, tube down, in press plate,
and remove air valve assembly
using a 3/8" drive extension as a
remover. See Figure 9-28.
11. The removal of the air valve
push rod assembly disassembles
the following p a r t s from the
power piston; the floating control
valve assembly, floating valve re-
tainer, push rod limiter washer
and air filters.
12. Remove the two "O" rings
from the grooves in the master
cylinder piston rod.
13. The push rod, floating control
valve and air valve must be serv-
iced as an assembly and cannot be
further disassembled.
9 - 1 8 CLEANING,
INSPECTION AND
REPLACEMENT
OF PARTS
a. Cleaning of Parts
1. Use Del-clean or clean brake
fluid to clean all metal brake
parts thoroughly. Immerse in the
cleaning fluid and brush with hair
brush to remove foreign matter.
Blow out all passages, orifices,
and valve holes. Air dry and
place cleaned parts on c l e a n
paper or lintfree clean cloth.
2. If slight rust is found inside
either the front or rear half hous-
ing assemblies, polish clean with
crocus cloth or fine emery paper,
washing clean afterwards.
NOTICE: Dirt is the major cause
of trouble and wear in service.
Be sure to keep parts clean until
reassembly. Re-wash at reas-
sembly, if there is any occasion
to doubt cleanliness — such as
parts dropped or left exposed for
eight hours or longer.
CAUTION: If there is any sus-
picion of contamination or any
evidence of corrosion, completely
flush the hydraulic brake system
in accordance with paragraph 9-7.
Figure 9-28—Removing Air Valve
Assembly
Failure to clean the hydraulic
brake system can result in early
repetition of trouble. Use of gas-
oline, kerosene, anti-freeze alco-
hol or any other cleaner, with
even a trace of mineral oil, will
damage rubber parts.
b. Inspectidn & Replacement
of Parts
1. Inspect all rubber parts. Wipe
free of fluid and carefully inspect
each rubber part for cuts, nicks,
or other damage. These parts are
the key to the control of fluid or
air flow, and should account for
the majority of troubles traceable
to leakage. Re-use rubber parts
only if a fairly new Unit is dis-
mantled for s o m e particular
trouble, and only then if there is
no doubt that the parts are in
equal-to-new condition. B a d l y
damaged items, or those which
would take extensive work or time
to repair, should be replaced. In
case of doubt, install new parts
for safety and for ultimate lower
cost.
2. Inspect in accordance with the
following table: (The table is or-
ganized by p o w e r b r a k e unit
groups.)