Pontiac FIREBIRD 1972 Service Manual page 485

5D-8 1972 PONTIAC SERVICE MANUAL
PRIMARY POWER MASTER CYLINDER,
s
PISTON BEARING
FRONT HOUSING SEAL
BOO
\
'X\\\\
\
FRONT HOUSING
POWER PISTON
RETURN SPRING
R PISTON GROUP
REAR HOUSING
POWER CYLINDER
DISASSEMBLE (Fig. 5D-6)
1. Clean exterior of power cylinder.
Fig. 5D-6 Power Cylinder
-
Exploded View
2. Scribe a line across front and rear housings to facili-
tate reassembly.
3. Remove front housing seal.
NOTE: Special too/ BT 7 M or J 23456 (Fig.
5D- 7) may be used for housing disassembly as
an alternate to the following method.
4. Attach tool J 22805-01 to master cylinder studs of
power cylinder with two nuts.
5. Place assembly in vise. Attach tool J 9504 over rear
housing studs. (Fig. 5D-8).
CAUTION: When separating housings, rotate
slowly as unit is under spring tension.
6. Applying downward pressure, rotate rear housing
counterclockwise to unlock housings. It is normal for
this operation to require heavy pressure to unlock
housings.
7. Remove rear housing and power piston assembly by
lifting straight up slowly and lay it aside on a clean
smooth surface.
8. Remove power piston return spring and retainer
plate.
9. Dispose of vacuum check valve grommet in front
housing.
10. Remove boot retainer and boot from rear housing.
The boot and felt silencer must be pulled over the
pushrod "eye" to remove.
11. Remove power piston group from rear housing and
remove primary piston bearing from center opening
of rear housing.
POWER PISTON
DISASSEMBLE (Fig. 5D-9)
CAUTION: Exercise extreme care in handling
power piston, rubber surfaces and metal parts
in this assembly. They should be guarded
against grease, oil and foreign matter and must