Chevrolet 10 Series 1970 Service Manual page 308

BRAKES 5-70
NAIL
F ig . 118—Super F a il Safe B reather
IM PORTANT: R eplace sealing compound o v e r
cap lock rin g to sea l unit fro m outside con­
tamination. A ssem b ly is accom plished in r e ­
v e rs e o rd e r o f d isassem b ly.
BREATHER ASSEMBLY
IMPORTANT: Do not rem ove b reath er a ssem ­
bly fro m cap unless inspection indicates dam ­
age. It is n ecessary to cut the nail to rem ove
the assem bly.
Breather System Assem bly (Fig. 118)
1. In sert nail through opening in seal.
2. In sert assem bly through opening in cap.
3. In sert spring o v e r nail.
4. F o rc e retain er o v e r fla re d end of nail.
Breather Assembly (Foam Type) (Fig. 118)
The foam breath er assem bly can be rem oved fo r clean ­
ing by rem oving the two screw s holding the breather
cap in p lace. Wash in cleaning solvent (non-toxic) and
re in s ta ll.
Fail-Safe Not Holding
P o w er spring not fu lly rele a se d (re q u ire s
F o r 1970 tr a ile r a ir brake equipment is available fo r
som e m odels. The option includes a hand con trol v a lve,
double check valve, push pull va lve, tr a ile r connectors,
BREATHER
18 to 21
TRAILER EQUIPMENT
GENERAL DESCRIPTION
F ig . 119— Super F a il Safe Tool D im ensions
turns counterclockw ise o f re le a s e b o lt)—Brake out o f
adjustment (.060" drum to lining clearan ce maximum)
Hold o ff a ir p ressu re not relea sin g fu lly —P o w er spring
fa ilu re .
Brake Dragging
Low F a il-S a fe hold o ff p ressu re (re q u ire s 65 p si).
Leaking Fail-Safe
Leaking at head o f the re lea se bolt indicates leakage
at eith er the piston o r
these leaks can be c o rrec te d by cyclin g the piston with
the spring uncaged by applying and relea sin g a ir pressu re
—Leaks at the b reath er assem bly on the cap also in di­
cate leakage at eith er the housing o r piston
both—This condition also w ill be noted i f the F a il-S a fe
and s e rv ic e brake a re applied at the same tim e. A ir
w ill be vented through the cap breath er. This is norm al
and not a malfunction o f the system .
Leaking Non-Pressure Housing
Leakage through the ports in the non-pressure housing
indicates diaphragm fa ilu re.
separate stop light switch and connecting lin es (fig . 120).
T estin g and se rvic in g o f these units is outlined in this
section.
rele a s e bolt " O " ring. Often
" O"
rin g o r
CHEVROLET TRUCK SERVICE MANUAL