Hydraulic System; Master Cylinder - Pontiac Grand Prix Service Manual

5-10
1 -
PONTIAC SERVICE MANUAL
1. Clevis 15. Secondary Piston
2. Boot (Front)
3. Push Rod Retainer
16. Primary Seal
4. Push Rod Protector
5. Snap Ring 17. Primary Seal
6. Secondary Seal 18. Spring Retainer
7. Primary Piston 19. Secondary Piston
(Rear) Spring
8. Protector Washer 20. Master Cylinder
9. Primary Cup Casting
10. Spring Retainer
21. Stop Bolt
11. Primary Piston
22. Reservoir Diaphragm
Spring 23. Reservoir Cover
12. Secondary Piston Stop
24. Reservoir Retaining Bail
13. Piston Extension 25. Check Valves Springs
Screw 26. Check Valves
14. Secondary Seal
27.
Tube
Seat Inserts
Fig. 5-12 Master Cylinder
-
Exploded View
17. Install wheels. Tighten nuts (Pontiac) 75 lb. ft.
(Tempest, Grand Prix and Firebird) 70 lb. ft. torque.
18. Check brake pedal travel to be sure it is within
specifications, then road test car for proper operation
of the brake system.
CA UTION:' New linings must be protected fiom severe
usage for several hundred miles. This should be conveyed
to owner, along with instructions to follow proper
burnishingprocedure as outlined in Ownefs Manual.
HYDRAULIC SYSTEM
The dual master cylinder is designed and built to
satisfy individual brake system displacement require-
ments (Fig. 5-4). Therefore, it is necessary that the
following basic rules be used when replacing either a
complete master cylinder or parts.
1. The two-letter identification stamp on the end of
master cylinder indicates displacement capabilities of a
particular cylinder. The master cylinder should only be
replaced with another cylinder bearing the same
two-letter identification (see Master Cylinder Usage
Chart), Fig. 5-14.
2. The lengths of component pistons in a master
cylinder are critical factors in displacement capabilities
of a master cylinder. Pistons are coded, using rings or
grooves in shank of piston. When pistons are replaced,
replacement piston must contain same identification
marks and same contour at push rod end as piston
which was removed.
3. The dual master cylinder, used with standard
brakes, contains a rubber check valve and check valve
spring in each outlet boss. No check valve is required
for disc brakes and, therefore, the outlet boss to the
front brakes will not contain a check valve and spring.
MASTER CY Ll NDER
11. Check to see that adjuster lever can turn adjusting
screw
star wheel with minimum of effort.
REMOVE
12. Adjust brake shoe-to-drum clearance as outlined
under ADJUSTMENT.
13. Install drums, observing instructions for front
wheel bearing adjustment as outlined in Section 3 of
this manual.
14. If wheel cylinder has been replaced or repaired, or
hydraulic. line has been replaced, bleed brakes as
described in this section on BLEEDING BRAKES.
15. Check parking brake cable adjustment and, if
necessary, adjust as outlined under PARKING
BRAKE -ADJUSTMENT.
16. Check fluid level in master cylinder as shown in
Fig. 5-4.
1. D i s c o ~ e c t master cylinder push rod from brake
pedal.
2. Disconnect brake lines from two outlets on master
cylinder and cover end of lines and outlet ports to
prevent entrance of dirt.
3. Remove master cylinder from dash.
DISASSEMBLE
1. Remove master cylinder reservoir cover and drain
fluid. Pump fluid from master cylinder by depressing
push rod.
2. A retained push rod
is
used on all standard brake