Chevrolet 70 Series 1970, Service Manual

Page: 354 / 841

BRAKES 5-63
for illu stra tio n s of this operation and dim ensions
to make a "strap” wrench.
7. R em ove w asher and O -rin g from p r e ssu r e
housing.
8
. R em ove p iston a ssem b ly from cap by p u ll­
ing straight out. At tim e s the spring, when fully
co m p ressed , cock s slig h tly . It is then n e c e ssa r y
to lo o sen the r e le a s e bolt a few turns so that the
p iston can be withdrawn ea sily .
9. The piston , retain er plate, s e a l and expand­
e r a r e held together by r iv e ts . If any part of this
a ssem b ly is d efective the com plete a ssem b ly must
be rep laced . D e ta ils a r e not se r v ic e d sep arately.
10. Cap and spring a ssem b ly is s e r v ic e d a s a
unit. If any of the p a rts becom e damaged or need
replacing, it is n e c e ssa r y to rep lace the com plete
cap and sp rin g a ssem b ly .
CAUTION: DO NOT attempt to dis­
assemble the cap and spring assembly. In
the event any part of this assembly is de­
fective, the complete assembly must be
Replaced. The component parts are not
serviced separately.
CLEANING AND INSPECTION
(R efer to F ig s. 37 and 38)
1. It is recom m ended that a ll brake cham bers
b e rem oved, d isa ssem b le d , inspected, and thor­
oughly cleaned at the tim e that brakes a re relin ed
or at one y ea r p er io d s, w hichever o ccu rs fir st
(a lso dependent upon type of operation and o p er­
a to rs exp erien ce).
2. Clean a ll m etal p arts thoroughly, u sin g a
su itab le cleaning fluid. B low dry with a ir o r wipe
dry with cloth.
Figure 40—Removing “Fail-Safe" Assembly
3. Inspect p iston cap for sig n s of damage or
e x c e s s iv e w ear. P iston should slid e fr e e ly in sid e
cap a ssem b ly . R ep lace piston if badly worn or
damaged.
4. Inspect in sid e w a lls of cap assem b ly for
sc r a tc h e s, s c o r e s , or e x c e s s iv e w ear. Slightly
worn sp ots may be rem oved with crocu s cloth.
CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL