Chevrolet 70 1969 Series, Shop Manual

Page: 254 / 913

BRAKES 5B-61
1 Spanner Nut Retaining Washer
9 Washer 17 Housing to Plunger " O " Ring
2 Spanner Nut
10 Bolt 18 Air Chamber Piston Plunger
3 Wedge Rod Guide 11 Non-Pressure Housing Assembly
4 Tag Nut
12 Push Rod Boot 19 Air Chamber Cap Assembly
5 Caution Tag 13 Diaphragm Plate Rod 20 Release Bolt Spring Lock
6 Nut
14 Rubber Diaphragm 21 Capscrew
7 Lock Washer 15 "Fail-Safe" Pressure Housing 22 Lock Washer
8 Clamping Ring 16 Housing to Cap Rubber Washer
r-7269
Figure 3 7 —“Fail-Safe" A h Chamber Components
SERVICING “FAIL-SAFE” BRAKE
CHAMBERS
Brake chamber components can be removed
from the vehicle for inspection and replacement of
parts without removing the non-pressure housing
and without disturbing the mechanical actuating
mechanism.
R E M O V A L A N D D IS A S SEM B LY
Refer to figure 36 (also refer to figure 37 for
components).
C A U T I O N : B E F O R E A T T E M P T IN G BR AKE
C H A M B E R R E M O V A L , B L O C K W H E E L S S E ­
C U R E L Y , SINCE PAR KIN G B R A KE W I L L N O T
BE APPLIED.
1. With air pressure in parking brake cham­
ber (brake released), loosen release bolt spring
lock and swing to one side; then turn release bolt
clockwise as far as it will go (approx. 18 turns)
to compress the power spring. Refer to figure 38.
2. Exhaust air pressure from parking brake
chamber by pulling parking brake knob out.
3. Disconnect air lines from both chambers,
4. Mark pressure housing and non-pressure
housing so that parts can be reassembled in the
same relative position. Loosen clamping ring by
unscrewing bolt. Hang clamping ring on non-pres­
sure plate tube.
5. Remove entire cap and spring assembly,
pressure housing, and rubber diaphragm (see fig.
39). Diaphragm plate rod and boot will remain in
the non-pressure housing.
6. Mount pressure housing in vise. N O T E :
Do not tighten vise jaws enough to distort pressure
housing. Using a wrench on hex end of cap, un­
screw cap and spring assembly from housing; O R
mount hex end of cap in vise and, using special
"strap" type wrench to remove pressure housing
Figure 38 — Compressing
“Fall-Safe''
Pow er Spring
CM EV W X ET S W S 5 7 0 -V 0 IR A V Y i;UTT TRUCK SH O P M A N U A L