Disassembly Of Master Cylinder; Assembly Of Master Cylinder; Power Unit Mounted In Press; Removing Center Plate From Rear Shell - Pontiac Grand Prix Service Manual

5C -4 1969
PONTIAC SER
.VICE MANUAL
4. Remove square ring seal from shoulder of plate.
NOTE: Seal may stick to shoulder of either front or rear
plate.
5. Using small rod or screwdriver through center bore
of front plate, push out reaction disc.
6. Loosen front diaphragm from center plate and slide
center plate carefully off front plate hub.
CAUTION: DO NOT DAMAGE OR REMOVE
SEAL FROM CENTER BORE OF CENTER PLATE.
DISASSEMBLY OF MASTER CYLINDER (Fig. 5C-6)
Always use the correct master cylinder repair kit when
overhauling the master cylinder. Always replace all
rubber parts. Metal parts cleaner should NOT be used
on any parts used in the hydraulic section. Gasoline
and kerosene also should never be used. Rinse all
hydraulic parts in clean alcohol. If the bore contains
rust, corrosion or pitted areas, clean with crocus cloth
only.
1. Pry water and dirt seal and retainer out of shallow
cavity around master cylinder hub.
2. Move rear piston with round-end rod to relieve
spring load on piston stop screw under master cylinder
bore. Use a 3/8" wrench to remove stop screw and
O-ring seal. Maintain pressure on rear piston and use
Tru-Arc pliers to remove snap ring from groove in
master cylinder bore.
3.
Remove rear piston and spring assembly and
discard. Do NOT attempt to disassemble it since a
complete new assembly is provided in the repair kit.
4. Remove front piston assembly, front return spring
and ret*r. Slide primary cup and protector off nose
of front piston. Use dull scribe to lift both secondary
seals from the grooves at the rear end of the piston.
Discard
all
old rubber parts.
NOTE: Check valves should not be replaced unless one
or more of conditions exist as outlined in Section 5
under Master Cylinder Disassembly.
NOTE: On master cylinder used with disc brakes, outlet
for front wheels does not incorporate a check valve and
spring. Tube seat should only be removed when the tube
seat, itselfl is damaged and requires repkcement.
CLEANING
Wash all hydraulic system parts in alcohol. Remove
spots, deposits or pitted areas inside the master
cylinder bore with crocus cloth. Discard all old rubber
parts, except reservoir diaphragm.
Fig. 5C.3A Power Unit Mounted in Press
INSPECTION
Inspect all metal parts for damage or excessive 'wear.
Replace any damaged or worn parts.
ASSEMBLY
ASSEMBLY OF MASTER CYLINDER (Fig. 5C-6)
1. Clamp master cylinder in vise with open end tilted
slightly upward.
Fig. 5C4 Removing Center Plate From Rear Shell