Buick LeSabre 1965 Service Manual page 557

BRAKES
POWER BRAKES 9 - 3 5
that the metal of the support plate
can be gripped with the hands.
10. With power piston still posi-
tioned on the holding tool in vise,
coat bead of diaphragm that con-
tacts power piston with Power
Brake Lube.
11. Holding the support plate on
the bare metal, with the locking
tangs down, place the support
plate and diaphragm assembly
down over the tube of the power
piston. The flange of the dia-
phragm will fit into the groove on
the power piston. See Figure
9-31.
12. Press down and rotate the
support plate counterclockwise,
until the lugs on the power piston
come against the stops on the
support plate.
13. This assembly can now be
turned o v e r and placed, tube
down, in a padded vise (Do Not
Clamp).
14. With a pair of #2 Truarc or
#J-4880 P l i e r s , assemble the
snap ring into the groove in the
air valve.
15. Place the air valve spring
retainer to seat on the snap ring.
Assemble the reaction bumper in-
to the groove in the end of the
air valve.
16. Position the air valve return
spring, large end down, on the
spring retainer.
17. The three reaction levers are
now placed into position with the
ears on the wide end, in the slots
provided for them in the power
piston. The narrow ends will rest
on the top of the air valve return
spring.
18. Position the reaction plate
(with numbered side up) on top
of the reaction levers. Press
down on the plate until the large
ends of the reaction levers pop up
so that the plate rests flat on the
levers. Be sure the reaction plate
is centered.
19. The master cylinder piston
rod and reaction retainer assem-
bly is now assembled to the power
piston.
20. With the round end of the pis-
ton rod up, and with the reaction
retainer held toward the top of
the piston rod, place the small
end of the piston rod in the hole
in the center of the reaction plate.
Line up the ears on the reaction
retainer with the notches in the
power piston and push the reac-
tion retainer down until the ears
seat in these notches.
21. Maintain pressure on the r e -
action retainer and position the
large lock ring down over the
master cylinder push rod.
22. There is a lug on the power
piston which has a raised divider
in the center. One end of the lock
ring goes under the lug and on one
side of the divider. See Figure
9-32.
23. As you work your way around
the power piston (either way) the
lock ring goes over the ear of the
reaction retainer, under a lug on
Figure 9-32—Installing Power Piston
Lock Ring
the power piston, and so forth,
until the other end of the lock ring
is seated under the lug with the
raised divider.
Be sure both ends of the lock ring
are securely under the large lug.
c. Assembly of Rear
Housing Group
1. Place a new p o w e r piston
bearing in center of rear housing
so that the flange on the center
hole of h o u s i n g f i t s into the
groove of the power p i s t o n
bearing. The large flange on the
power piston bearing will be on
the stud side of the housing.
2. Coat the inside of the power
piston bearing with Power Brake
Lube.
d. Final Assembly of
Power Brake Unit
1. Place the air silencer over the
holes on the tube of the power
piston. Wipe the tube of the power
piston with Power Brake Lube.
2. Assemble the power piston to
the rear housing by pushing the
tube of the power piston through
the rear housing from the side
opposite the studs.
3. Wipe tube of the reaction re-
tainer with Power Brake Lube
and lay the assembly aside.
4. Place the front housing in a
vise with the master cylinder
down. Position power piston re-
turn spring over the inset in the
front housing. Lubricate the I.D.
of the support plate seal with
Power Brake Lube.
5. Lubricate lightly with talcum
powder the beaded edge of t h e
diaphragm. Hold the rear housing
and power piston assembly over
the front housing with the master
cylinder push rod down. Position
the rear housing so that when it is
rotated into the locked position,
the scribe marks on the housings
will be in line.