GMC 1990 Light Truck Repair Manual page 346

5-10 BRAKES
1. Boot
2. Silencer
3. Vacuum check Valve
4. Grommet
5. Front Housing Seal
6. Power Piston Bearing
7. Rear Housing
8. Front Housing
9. Return Spring
10. Piston Rod (Gaged)
11. Reaction Retainer
12. Filter
13. Diaphragm Retainer
14. Diaghragm
15. Diaphragm Support
16. Power Piston and
Pushrod Assem bly
19. Pushrod
25. Reaction Body
Retainer
Install or Connect (Figure 20)
Tools Required:
J 23456 Power Brake Booster Disassembly
and Reassembly Tool
J 28458 Power Piston Seal Protector
J 37839 Pushrod Height Gage
Diaphragm (14) into the diaphragm support (15).
• Lubricate the inside diameter of the dia­
phragm lip with a thin layer of silicone grease.
Diaphragm and diaphragm support onto the power
piston and pushrod assembly.
New diaphragm retainer (13) (figure 22).
• Seat the retainer using J 28458.
Filter (12), reaction retainer (11) and piston rod (10).
Reaction body retainer (25).
Figure 21—Unlocking and Locking Booster
Figure 20—Single Diaphragm Vacuum Booster Components
6. Power piston bearing (6) into the rear housing.
• Lubricate the inside and outside of the bearing
with silicone grease.
7. Power piston group into the rear housing (7).
8. Return spring (9).
9. Front housing to the rear housing.
• A lig n th e m a r k s m a d e d u r in g d is a s s e m b ly .
• Use J 23456 to apply force in a clockwise di­
rection to lock the front and rear housings.
• Stake the housing at two tabs 180 degrees
apart (figure 23).
— Do not stake a tab that has previously
been staked.
• Assembly can be aided by connecting a vac­
uum source to the booster.
10. Grommet (4) and vacuum check valve (3).
Figure 22—Installing the Diaphragm Retainer
F-05821