Pontiac FIREBIRD 1972 Service Manual page 472

1972 PONTIAC SERVICE MANUAL
2. Set 1-1/16" hex bar stock about 2" long or tool J
22839 in bench vise. Set Diaphragm and Plate assem-
bly on hex stock with hex opening in center of front
plate on bar. Twist rear plate counterclockwise, using
hand leverage only either on atmospheric pressure
channel or on outside circumference of rear plate.
After plates have been loosened, remove assembly
from vise and complete disassembly on bench, front
plate down.
3. Unscrew rear plate completely and carefully lift it off
front plate hub, grasping valve plunger and spring
with other hand and remove them from bore of front
plate hub.
4. Remove square ring seal from shoulder of plate. 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 PLA TE.
MASTER CYLINDER
DISASSEMBLE (Fig. 5C-12)
Always use the correct master cylinder repair kit when
overhuling the master cylinder. Always replace all rub-
ber parts.
CAUTION: Metalparts cleaner should NOT be
used on any parts used in the hydraulic system.
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 blunt tool 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 snap
ring pliers to remove snap ring from groove in master
cylinder bore.
1.
Snap Rmg
2.
Splash Shleld Relalner
3.
Splash Seal
4. Secondary Seal
5.
Rear Piston and
Sorino A s s e d l v
Fig. 5C-12 Master Cylinder Exploded View