Pontiac tempest 1968 Service Manual page 189

5 A - 6
1968 P O N T I A C SERVICE MANUAL
PUSH ROD
BOOT
REAR
HOUSING
POWER PISTON
BEARING
MASTER
CYLINDER
FRONT
HOUSING SEAL
POWER PISTON
RETURN SPRING
VACUUM CHECK
VALVE
^ CHECK VALVE
GROMMET
FRONT
HOUSING
POWER PISTON
A S S E M B L Y
F i g . 5 A - 7 Exploded V i e w o f Firebird and Tempest Power Brake Unit
cylinder push rod. Wipe thin coat of power brake
lubricant on O-ring.
7. Place floating control valve retainer over push
rod so that flat side seats on floating control valve.
2. Insert vacuum cylinder push rod through re­
action retainer so that round end of rod protrudes
from end of tube on reaction retainer.
3. Place power piston installer, J 2 1 5 2 4 , in vise
and position power piston with three lugs fitting into
notches In piston.
4. Install new O-ring seal on air valve in second
groove from valve operating rod end.
NOTE; A new air valve assembly must be in­
stalled since floating control valve is a component
part of this assembly and cannot be disassembled.
5. Wipe thin film of power brake lube on large
O.D. of floating control valve and on O-ring of air
valve.
6. Press air valve - push rod floating control
valve assembly, air valve first, to its seat in tube of
power piston.
8. Start floating control valve and its retainer into
power piston tube. Use tool J 21601 to press floating
valve to seat in tube by placing tool on top of re­
tainer and pressing down.
9. Position push rod limiter washer over push rod
to floating control valve and install two air filter
elements over end of push rod and into power piston
tube.
10. Assemble power piston diaphragm to support
plate from side of plate opposite locking tangs and
press raised flange of diaphragm through hole in
center of plate.
NOTE: Be sure that edge of center hole fits into
groove in flange of diaphragm.
11. Pull diaphragm away from O.D. of support
plate so that the plate can be gripped with hands.
Wipe power brake lubricant on all surfaces of small
bead of diaphragm which contacts power piston.