Chevrolet 1980 Light Duty Truck Repair Manual page 160

5-24 BRAKES
F ig . 5 - 3 E ~ O u t p u t R o d , S p r in g a n d R e t a in e r
8. R em ove the booster assembly from the vise and
w hile holding the unit over a pan, separate the cover from
the housing. R em ove the "figure eight" seal from the
housing cover; discard the seal.
9. R em ove the input rod and piston assembly, the spool
assem bly and spool spring from the booster housing.
Compare spool valve condition to Figure 5-4E. If spool
valve is defective, the com plete unit m ust be replaced.
10. Inspect power piston. If scratches big enough to be
felt w ith a fingernail are present, the input rod and piston
m ust be replaced.
11. R em ove the input rod seals from the input rod end,
and the piston seal from the piston bore in the housing;
discard the seals.
12. Place the accum ulator retaining cap T ool J-26889
over the master cylinder stud and install the nut as shown
in Figure 5-6E.
13. U sing Tool J-22269-01 or a large "C" clam p (6"
m inim um ), depress the accum ulator. Insert a punch into the
hole in the housing and rem ove retaining ring with a sm all
screwdriver, (fig. 5-6E).
O V E R H A U L M A N U A L
14. Slow ly back o ff the clam p until tension on the
accum ulator is released; rem ove accum ulator and "O" ring.
15. If accum ulator valve was determ ined to be faulty,
rem ove valve using a sm all diameter wire tool (fig. 5-5E).
R em ove the dump valve by catching the tool under the pin
guide near the center o f the valve, then rem ove two function
valves and seat (fig. 5-8E).
16. Return hose fitting "O" ring can be rem oved if
leaking.
17. Push spool valve plug in and use a sm all
screwdriver to remove retaining ring (Fig. 5-9E).
18. R em ove spool valve plug and "O" ring.
19. R em ove the tube seats using N o. 4 easy-out as
shown in Figure 5-10E.
C leaning and Inspection
C A U T IO N : Be sure to keep parts clean
until reassem bly. W a s h a t reassem bly if
th e re are any parts
exposed for eig h t
Lubricate all seals and
dropped or le ft
hours or longer.
m etal frictio n