Buick LeSabre 1965 Service Manual page 556

9 - 3 4 POWER BRAKES
BRAKES
SUPPORT PLATE
REMOVER J-21524
Figure 9-29—Positioning Power Piston
in Wrench
9 - 1 9 ASSEMBLY OF
POWER BRAKE UNIT
Be certain that all rubber parts
are clean at reassembly. Re-wash
in Del-clean or clean brake fluid,
if there is any doubt of cleanli-
ness. Be careful during the r e -
build process that no grease or
mineral oil comes in contact with
the rubber parts of the power
b r a k e unit. Lubricate rubber
parts with Delco Moraine ap-
proved lubricant or equivalent.
a. Assembly of Front
Housing Group
1. Replace the vacuum c h e c k
valve, using a new grommet, if
old one is cracked or damaged.
2. Place new front housing seal
in the center of the front housing
so that the flat surface of the cup
lies against the bottom of depres-
sion in the housing.
b. Assembly of Power
Piston Group
On reassembly of the power pis-
ton, if the push rod, air valve,
and floating control valve have
oeen removed, they must be r e -
placed as an assembly with new
parts. Removing the push rod
distorts component parts in the
floating control valve mechanism.
1. Place two new "O" rings in
the grooves on the master cyl-
inder piston rod. Wipe a thin
film of #5459912 Power Brake
Lube or equivalent on the " O "
rings.
2. The master cylinder piston rod
is now inserted through the r e -
action retainer so that the round
end of the piston rod protrudes
from the end of the tube on the
reaction retainer.
3. Place the P o w e r P i s t o n
Wrench, J-21542 in a vise. Po-
sition the power piston on the
wrench with the three lugs fitting
into the notches in the power pis-
ton. See Figure 9-29.
SUPPORT PLATE
REMOVER AND
INSTALLER J-21524
Figure 9-30—Seating Floating Control
Valve Assembly
Figure 9-31—Installing Power Piston
into Support Plate
4. Wipe a thin film of power
brake lube on the large O.D. of
the floating control valve and on
the " O " ring on the air valve.
5. Start the air valve-push rod-
floating control valve assembly
into the tube of the power piston.
6. Use J-21601 Floating Control
Valve Retainer Installer to manu-
ally press assembly and retainer
to seat in tube. See Figure 9-30.
7. Install f i l t e r e l e m e n t s by
stretching over end of push rod
and pressing into tube.
8. Assemble the power piston
diaphragm to the diaphragm sup-
port plate from the side of the
support plate opposite the locking
tangs. The raised flange of the
diaphragm is pressed through the
hole in the center of the support
plate. Be sure that the edge of
the center hole fits i n t o the
groove in t h e f l a n g e of t h e
diaphragm.
9. Pull the diaphragm away from
the O.D. of the support plate so