Table of Contents
Advertisement
5-56
1977 PONTIAC SERVICE MANUAL
ASSEMBLY OF DELCO MORAINE
POWER BRAKE UNIT
Be certain that all rubber parts are clean at reassembly.
Rewash in specified cleaning fluid if there is any doubt of
cleanliness. Be careful during rebuild process that no grease
or mineral oil comes in contact with rubber parts of power
brake unit. Lubricate rubber parts with Delco Moraine
approved lubricant or equivalent.
Assembly of Front Housing
G ; O U ~
1.
Replace vacuum check valve using a new grommet if
old one is cracked or damaged.
2.
Place new front housing seal in housing so flat surface
of cup lies against bottom of depression in housing.
Assembly of Power Piston Group
1.
Place new " 0 " ring in groove on the master cylinder
piston rod. Wipe a thin film of Power Brake Lube or
equivalent on " 0 " ring.
2.
Master cylinder piston rod is not inserted through the
reaction retainer so round end of piston rod protrudes from
end of the tube on reaction retainer.
3.
Place J
21524
power piston wrench in a vise. Position
power piston on wrench with three lugs fitting into notches
in power piston.
4.
Position new " 0 " ring on air valve in second groove
from push rod end.
5.
On reassembly of power piston, floating control valve
assembly must be replaced with a new one since the force
required to remove it distorts component parts.
6.
Place floating control valve on push rod-air valve
assembly so flat face of valve will seat against valve seat on
air valve.
7.
Wipe a thin film of Power Brake Lube on large O.D.
of floating control valve and on " 0 " ring on air valve.
8.
Press air valve push rod assembly, air valve first, onto
its seat in tube of power piston.
9.
Place floating control valve retainer over push rod so
flat side seats on floating control valve.
10.
Start floating control valve and its retainer into
power piston tube. Press the floating control valve to seat in
the tube, by placing J
21601-01
Floating Control Valve
Retainer Installer on top of retainer and pushing down by
hand. See Fig.
5-96.
11.
After floating control valve is seated, position push
rod limiter washer over push rod and down onto floating
control valve. Air filter element can now be streached over
end of push rod and pressed into power piston tube.
12.
Assembly power piston diaphragm to diaphragm
support plate from side of support plate opposite locking
tangs. The raised flange of diaphragm is pressed through hole
in center of support plate. Be sure that edge of center hole
fits into groove in flange of diaphragm.
13.
Pull diaphragm away from O.D. of support plate
support plate can be gripped with hands.
Fig. 5-95 Removing Air Valve Assembly
Fig. 5-96 Installing Floating Control Valve Assembly
14.
With power piston still positioned on holding tool
in vise, coat bead of diaphragm that contacts power piston
with Power Brake Lube.
15.
Holding support plate by metal, with locking tangs
down, place support plate and diaphragm assembly over tube
of power piston. The flange of diaphragm will fit into groove
on power piston. See Fig.
5-97.
16.
Press down and rotate support plate clockwise, until
lugs on power piston come against stops on support plate. See
Fig.
5-97.
17.
This assembly can now be turned over and placed,
tube down, in a tool, fabricated from a piece of wood,
2"
x
4"
x
8"
long with a
1-3/8"
hole in the center, clamped in a
vise.
18.
With a pair of No.
22
Truare or
J 4880
Pliers,
assemble snap ring into groove in air valve.
19.
Place air valve spring retainer on snap ring. Assemble
reaction bumper into groove in end of air valve.
20.
Position air valve return spring, large end down, on
spring retainer.
2 1.
The three reaction levers are now placed into position
with ears on wide end in slots in power piston. The narrow
ends will rest on top of air valve return spring.
22.
Position reaction plate (with numbered side up) on
top of reaction levers. Press down on plate until large ends
of reaction levers pop up so plate rests flat on levers. Be sure
reaction plate is centered.
23.
Master cylinder piston rod and reaction retainer
assembly is now assembled to the power piston.
Advertisement
Table of Contents
