Chevrolet 10 Series 1968, Service Manual

Page: 310 / 713

BRAKES 5-67
Disassem bly (Fig. 102)
1. Remove dirt and grease from outside of unit by
washing in a suitable cleaning fluid.
2. Cut off riveted ends of rivets attaching cover plates
to body. Drive out rivets and remove cover plates.
3. Remove welch plug from end of worm shaft bore.
Insert a flat end punch into the worm shaft bore and
drive worm shaft out of body and worm.
40 Remove lock sleeve and spring from worm shaft.
Remove gear and worm from slack adjuster body.
Inspection and Repair
1. Wash parts in cleaning fluid and wipe dry.
2. Inspect worm and gear and replace with new parts if
chipped or broken teeth are evident.
3. Inspect worm shaft for wear. Make sure corners on
hex end are not rounded.
4. Inspect bushing in lever arm. If worn, out-of-round,
or otherwise damaged, it must be replaced. To
replace bushing, press oil bushing out and press new
bushing into place. Bushing must be reamed after
installation to 0.503"-0.504".
5. Examine lock sleeve for cracks or other damage.
Replace if necessary.
6. Examine lever (body) for cracks or distortion. If
lever is damaged in any way, a new body and bushing
assembly must be used.
Assem bly (Fig. 102)
1. Place worm and gear assembly in position in body.
2. Place lock sleeve over worm shaft, with socket-like
end of sleeve at hex end of shaft. Place lock spring
in recess formed by sleeve and shaft.
3. Enter small end of worm shaft through hole in body
and worm. Press worm shaft into worm and body,
making sure the groove in lock sleeve is aligned with
pin in body. Press shaft in until distance from small
end of shaft to edge of body (A, fig. 102) is 0.625".
Install new welch plug in worm shaft bore.
4. Position cover plates on body and attach with new
rivets. Covers must be flat and in good contact with
body after riveting.
Installation
1. If a new slack adjuster is being installed, make sure
it is the same size and type as that removed. Make
sure spacing washer is in place on camshaft. Slide
the slack adjuster onto camshaft and attach with
spacer and lock ring.
2. Connect brake chamber push rod yoke to slack ad­
juster with clevis pin and cotter pin. Refer to
"Brake Chamber Installation" for adjustment of
brake chamber push rod.
3. Adjust brakes as previously directed under "Brake
Adjustments."
Lubrication
Slack adjusters are permanently lubricated by the man­
ufacturer and require no periodic lubrication. However,
if a slack adjuster has been dismantled and repaired in
accordance with these procedures, it becomes necessary
to lubricate upon reassembly„
1. Remove one plug from slack adjuster side plate.
2. Using a pressure grease gun, inject grease into the
hole in side cover while turning the wormshaft
approximately 50 revolutions in one direction.
3. Install side plug securely.
4. Rotate wormshaft three revolutions in the opposite
direction.
5. Refer to Section 0 - Lubrication in this manual for
additional information.
Slack Adjuster Operating Test
Apply brakes and make sure all slack adjusters rotate
freely and without binding. Release brakes and make
F ig . 104-Rear Brake Parts Identification
F ig . 103-Removing Camshaft (Front shown as T y p ic a l)
Actuating Cam
Roller
Brake Shoe Facing
Brake Shoe
5. Anchor Pin Lock Ring
6. Anchor Pin
7. Flange Plate
8. Shoe Return Spring
9. Roller Pin
CHEVROLET TRUCK SERVICE MANUAL