Valve Plunger Stop Key - Pontiac Grand Prix Service Manual

BENDIX POWER BRAKE
5B-3
6. Remove front vacuum seal with a blunt tool.
POWER PISTON
-
DISASSEMBLE (Fig. 56-4)
CA UTION: 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 be protected from nicks or cuts that
might be caused by rough surfaces or damaged tools.
1. Remove boot and foam filter from power unit.
2. Remove the foam air silencers. Be careful not to
chip plastic ho~ising.
3. Remove diaphragm plate (power piston) from rear
housing.
4. Carefully remove rubber diaphragm from dia-
phragm plate.
5. Tilt diaphragm plate and depress valve operating
rod slightly to remove valve assembly retainer (valve
plunger stop key). See Fig. 5B-3.
6. Pull control valve assembly straight out from
diaphragm plate and with a blunt tool, push reaction
disc out front of plate. Do not disassemble control
valve assembly
.
7. Inspect rear shell vacuum seal. Remove only if
necessary to replace by driving out with a screwdriver
or punch.
MASTER CYLINDER
-
DISASSEMBLE (Fig. 56-5)
1. Pry splash seal and retainer out of shallow cavity
around master cylinder hub.
e
2. Press in against rear piston with round-end rod to
relieve spring load on piston stop screw under master
cylinder bore. Use 3/8" wrench to remove stop screw
and O-ring seal. Maintain pressure on rear piston and
use Tru-Arc pliers to remove snap ring from groove in
master cylinder bore.
3. Remove rear piston and spring assembly and
discard. Do not attempt to disassemble it since
complete new assembly is provided in repair kit.
4. Remove front piston assembly, front return s e g
and retainer. Slide primary'cup and protector off nose
of front piston. Use dull scribe to lift both secondary
seals from the grooves at rear end of front piston.
Discard all old rubber parts.
NOTE: Check valves should not be replaced unless one
or more of conditions exist as outlined in Section 5
under Master Cylinder Disassemble.
ALVE
ASSEMBLY
PERATINO ROD
VALVE
PLUNG
Fig. 5B-3 Valve Plunger Stop Key
-
Remove and
Install
out the tube fitting insert with a 13/64" drill and then
tap the hole, using a 1/44'
x
20 tap. Place a 1/2" to
3/4" long, 1/4"
x 20
bolt through a thick washer and
then thread the bolt into the insert. Tighten the bolt
against the washer until the insert is removed.
6. Remove check valves and springs from cavities
beneath tube seats and discard.
INSPECTION
-
CLEANING
Thoroughly wash all parts in alcohol and air dry. Blow
dust and cleaning fluid out of all internal passages. If
DIAPHRAGM
RETURN SPRING
CONTROL VALVE
ASSEMBLY
STOP KEY
5. With master cylinder in vise, (outlet holes up) drill
Fig. 5B-4 Power Piston
-
Exploded View