Chevrolet 70 1969 Series, Shop Manual

Page: 255 / 913

BRAKES 5B-62
Figure
39—Removing
“ F a il-S a fe ” A ss e m b ly
from cap assembly. See figures 40 and 41 for il­
lustration of this operation and dimensions to
make a "strap" wrench.
7. Remove washer and O-ring from pressure
housing.
8. Remove piston assembly from cap by pull­
ing straight out. At times the spring, when fully
compressed, cocks slightly. It is then necessary
to loosen the release bolt a few turns so that the
piston can be withdrawn easily.
9. The piston, retainer plate, seal and expand­
er are held together by rivets. H any part of this
assembly is defective the complete assembly must
be replaced. Details are not serviced separately.
10. Cap and spring assembly is serviced as a
unit. If any of the parts become damaged or need
replacing, it is necessary to replace the complete
cap and spring assembly.
C A U T IO N : Do not attempt to disassemble the
cap and spring assembly. In the event any part of
this assembly is defective, the complete assembly
must be replaced. The component parts are not
serviced separately.
C L E A N IN G A N D IN SPEC TION (Figs. 36 and 37)
1. It is recommended that all brake chambers
be removed, disassembled, inspected and thor­
oughly cleaned at the time that brakes are relined
or at one year periods, whichever occurs first
(also dependent upon type of operation and oper­
ators experience).
2. Clean all metal parts thoroughly, using a
suitable cleaning fluid. Blow dry with air or wipe
dry with cloth.
3. Inspect piston cap for signs of damage or
excessive wear. Piston should slide freely inside
cap assembly. Replace piston if badly worn or
damaged.
4. Inspect inside walls of cap assembly for
scratches, scores, or excessive wear. Slightly
worn spots may be removed with crocus cloth.
Inspect external threads on cap for rust or cor­
rosion.
Figure 4 0 — Rem oving Pressure Housing with “Strap" Wrench
CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L