GMC C Series 1993, Руководство по ремонту

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5A-2 MASTER CYLINDER
GENERAL DESCRIPTION
The Bendix tandem master cylinder has a primary
and secondary hydraulic system. Each system has a
separate piston. One piston delivers pressure to the
front brakes and the other delivers pressure to the rear
brakes.
These; master cylinders have identifying information
stamped on a pad on the left side of the mounting
flange.
.' ■ ■ ii!!U !: ■
'.jllil ji,:’ '
U N IT RERAIR
MASTER CYLINDER
4 4 Remove or Disconnect (Figure 1)
1. Reservoir caps (1) and diaphragms (2).
• Pump the piston to aid in fluid removal.
2. Four bolts (26).
3. Reservoir (3).
4. O-rihg (29).
5. Compensating valve seals (4).
6. Compensating valve poppets (5).
7. Compensating valve springs (6).
8. Stop pin (28).
• Depress the primary piston.
9. Snap ring (13) while the primary piston is
depressed.
10. Primary piston (14).
11. Retaining ring (19). i|i’
12. Primary actuator (18).
13. Primary actuator spring (17).
.
14. O-rihg seal (16).
15. Seal backup (15).
16. Primary piston return spring (20).
CAUTION: In the following step, if air pres­
sure is used to remove the secondary piston;
place the open end of the cylinder bore
approximately 25 mm (1 inch) from a padded
workbench or other surface to catch the pis­
ton when it comes out of the bore. Apply low
air pressure very carefully to ease the piston
out of the bore. The open end of the bore
must never be pointed at anyone while apply­
ing air pressure. The piston may come out of
the bore with considerable force and cause L
personal injury.
17. Secondary piston (23).
• It may be necessary to plug the front outlet port
and apply a small amount of air pressure to the
front compensating valve port.
18. O-ring seal (21).
19. Seal backup (22).
20. O-ring seal (25).
21. Seal backup (24).
22. Secondary actuator spring (12).
23. Secondary actuator (11).
24. Caging bolt (10).
25. Secondary piston return spring (9).
g Glean
• All riibber parts with clean brake fluid.
• All ipidtal parts with denatured alcohol.
• All! jiniake and by-pass ports in the cylinder hous-
• The; ibleeder holes in the piston.
NOTICE: Do n o t use em ery clo th o r sand
paper, deep scratching can o ccu r w ithin the
cylih'dei' i f anything coarser than crocus cloth
is used.
• Polish any discolored or stained area with crocus
cloth. '
] f Inspect
4 4
• Cylinder bores for scoring or corrosion. Replace if
■ found:.;1 | .
• Reservoir for cracks. Replace if found,
install or Connect (Figure 1)
T. Secondary piston return spring (9).
2. Caging bolt (10).
3. Secondary actuator (11).
4. Secondary actuator spring (12).
5. Secondary piston (23).
• Lubricate the piston assembly with clean brake
; fluid.
6. O-ring seal (21).
7. Seal! backup (22).
8. O-ring seal (25).
9. Seal! backup (24).
10. Secondary piston assembly into the master cylin­
der bore. '
11. Primary piston return spring (20).
12. Pijimatry piston (14).
, HiLitlbricate the piston assembly with clean brake
■ ,:,i i Jjfjbid.
13. Seal ibackup (15).
14. -Orfji!n^!seal (16).
15. Primary actuator spring (17).
16. Primary actuator (18).
17. Retaining ring (19).
18. Primary piston assembly into the bore past the
snap ting groove.
’• Depress and hold the primary piston.
19. Snap nng (13) into the bore groove.
20. Stop pin (28).