GMC S Series 1994, Repair Manual

Page: 289 / 919

1. Boot
2. Silencer
3. Vacuum Check Valve
4. Grom met
7. Front Housing Seal
8. Primary Piston Bearing
9. Rear Housing
10. Front Housing
11. Return Spring
12. Piston Rod (Gaged)
13. Reaction Retainer
14. Power Head Silencer
15. Diaphragm Retainer
16. Primary Diaphragm
17. Primary Support Plate
18. Secondary Piston Bearing
19. Housing Divider
20. Secondary Diaphragm
21. Secondary Support Plate
22. Reaction Disc
23. Reaction Piston
24. Reaction Body Retainer
25. Reaction Body
26. Air Valve Spring
27. Reaction Bumper
28. Retaining Ring
29. Filter
30. Retainer
31. O-Ring
32. Air Valve Push Rod Assembly
33. Power Piston
41. Power Piston Assembly
11
10
F9157
Figure 5— Dual Diaphragm Vacuum Booster Components
3. Diaphragm and diaphragm support on power piston
and pushrod assembly.
4. New diaphragm retainer (13) (figure 3).
• Seat the retainer using J 28458.
5. Filter (12), reaction retainer (11), and piston rod
(
10
).
6. Reaction body retainer (25).
7. Power piston bearing (6) in rear housing.
8. Lubricate inside and outside of bearing with Delco
Silicone Lube (GM P/N 18010909) or equivalent.
9. Power piston group in rear housing (7).
10. Return spring (9).
11. Front housing (8) to rear housing (7).
A. Align marks made during disassembly.
B. Use J 23456 to apply force in a clockwise direc­
tion to lock the front and rear housings.
C. Stake the housing at two tabs 180 degrees
apart (figure 4).
Notice: Do not stake a tab that has previous­
ly been staked. The tab may break at a later
time and system failure may occur.
• Assembly can be aided by connecting a
vacuum source to the booster.
12. Grommet (4) and vacuum check valve (3).
13. Lubricate inside and outside diameters of grommet
and front housing seal with a thin layer of Delco
Silicone Lube (GM P/N 18010909) or equivalent.
14. Front housing seal (5).
15. Silencer (2) and boot (1).
tU Measure
Booster pushrod length. Refer to “ Gaging Proce­
dure.”
DUAL DIAPHRAGM
Remove or Disconnect (Figures 1, 5, 6, and 7)
Tool Required:
J 23456 Power Brake Booster Disassembly and
Reassembly Tool