Chevrolet 70 1969 Series, Shop Manual

Page: 268 / 913

BRAKES 5C-75
anchor bracket is placed over anchor bar.
2. Install anchor screw through bracket and
spring into anchor bar. Insert locating bolt up
through band lower bracket and hole in support
and install nuts temporarily.
3. Place operating cams between links and
install new clevis pin and cotter pin.
4. Insert threaded end of adjusting bolt down
between operating cams with hook toward rear of
vehicle. As bolt is lowered into place it must pass
through cam shoe, band upper bracket, upper re­
lease spring, brake support, lower release spring,
and band lower bracket. Install tension spring,
flat washer, adjusting nut, lock washer, and lock
nut on adjusting bolt.
5. Adjust lining to drum clearance and con­
nect brake rod as directed under "Band Type Ad­
justment."
BR AKE D R U M R E M O V A L
1. Remove brake band and lining assembly.
2. Remove nuts and lock washers from bolts
attaching propeller shaft U-joint flange and brake
drum to transmission output shaft flange. Teles­
cope propeller shaft at slip joint and lower end of
propeller shaft to floor. Remove if necessary, nuts,
lock washers, and bolts attaching propeller shaft
center bearing hanger bracket to crossmember.
3. On some vehicles, brake drum is mounted
on forward side of transmission mainshaft com­
panion flange, and on other vehicles it is mounted
on rear side of flange. If mounted on rear side of
flange, drum may be removed without removing
flange; if mounted on forward side of flange, re­
move retaining nut and flange from output shaft.
Press serrated bolts from flange to separate drum
from flange.
BR AK E D R U M IN S T A L L A T IO N
1. Wipe mating surfaces of brake drum and
output shaft flange clean. Position brake drum on
flange and press serrated bolts into place. Replace
drum assembly and retaining nut on output shaft.
See "Specifications" in "T R A N S M IS S IO N " (SEC. 7B)
for nut torque on various transmission models.
2. Position propeller shaft flange against brake
drum (or output shaft flange). If removed, attach
propeller shaft center bearing hanger bracket to
crossmember. Replace all lock washers and nuts
and tighten securely.
3. Install brake band and lining assembly and
adjust brake.
INTERNAL EXPANDING TYPE BRAKE
Internal expanding type parking brake is mount­
ed at rear of transmission. Brake support plate is
attached to transmission rear bearing cap or re­
tainer with four bolts. Brake drum is mounted be­
tween universal joint flanges and is secured with
eight bolts. When used as an emergency brake, at
start of braking action, brake shoes are forced
out against drum by a lever-operated cam. The
self-energizing action of both shoes then completes
brake application.
N O T E : Except in case of an emergency, set
parking brake only after vehicle is brought to a
complete stop. Parking brake is not designed for
regular use in place of service brakes.
PARKING BR AKE A D J U S T M E N T (Fig. 2)
A brake adjustment should be made before it
becomes necessary to pull hand brake lever to
limit of travel to obtain a full brake application.
1. Jack up at least one rear wheel. Block
wheels and release hand brake.
2. Remove cotter pin and clevis pin connecting
pull rod and relay lever. This will assure freedom
for full shoe release.
3. Rotate brake drum to bring one of access
holes into line with adjusting screw at bottom of
shoes.
4. Expand shoes by rotating adjusting screw
with screwdriver inserted through hole in drum.
Move outer end of screwdriver away from drive
shaft. Continue adjustment until shoes are tight
against drum and drum cannot be rotated by hand.
Back off adjustment four (4) notches and check drum
for free rotation.
5. Place parking brake lever in fully released
position. Take up slack in brake linkage by pulling
back on control lever just enough to overcome
spring tension. Adjust clevis of pull rod to line up
with hole in relay lever. Insert clevis pin and cotter
pin, then tighten clevis lock nut.
Figure 2 — Internal Expanding Type Brake Adjustment
CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP M ANUAL