Chevrolet 70 1969 Series, Shop Manual

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BRAKES 5B-28
PUSH LO C K SLEEVE IN TO
D IS E N G A G E HEAD O F W O RM
SHAFT TO M AKE ADJUSTMENT
LO C K SLEEVE MUST C O M E OUT
AND E N G A G E HEAD O F W O R M
SH A FT TO LO C K ADJUSTM EN T
1 Lock Sleeve
2 Spring
3 Dowel
4 Lever
5 Rubber Plug
6 W o r m
7 W o r m Shaft
8 Gear
9 Cover Plate
T -2 3 25
Figure 5— Slack Adjuster
SLACK ADJUSTERS
S L A C K A D J U S T E R O P E R A T IN G T E S T
Apply brakes and make sure all slack adjust­
ers rotate freely and without binding. Release
brakes and make sure all slack adjusters return
to released position freely without binding.
With brakes released, make sure the angle
formed by slack adjuster arm and brake chamber
push rod is greater than 90 degrees. All slack ad­
justers should be set at the same angle. With
brakes applied, make sure the angle formed by the
slack adjuster arm and brake chamber push rod is
still slightly greater than 90 degrees and that all
are at the same angle. If angle is less han 90 de­
grees with brakes applied, slack adjuster is going
"over center." Adjust brakes as previously des­
cribed under "Brake Adjustments."
S L A C K A D J U S T E R R E P L A C E M E N T
(Refer to Figs. 6 and 7)
Removal
1. Remove clevis pin attaching brake chamber
push rod yoke to slack adjuster.
2. Remove lock ring or cotter pin and spacer
securing slack adjuster on camshaft. Slide slack
adjuster off end of shaft.
Adjusting Worm Shaft
Lubrication Hole Plug
Clevis Pin
Slack Adjuster
Adjusting Clevis
Mounting Bracket
7 Brake Chamber
8 Air Brake Hose
9 Front Axle
10 Brake Camshaft
11 Snap Ring
Figure 6 — Brake Chamber and Slack Adjuster Installed (Front)
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 slack adjuster onto camshaft
and attach with spacer and lock ring or cotter pin.
2. Connect brake chamber push rod yoke to
slack adjuster with clevis pin and cotter pin.
Refer to "Brake Chamber Installation" for adjust­
ment of brake chamber push rod.
3. Adjust brakes as directed under ' Brake
Adjustments."
BRAKE CHAMBERS (STANDARD)
All service information in the following para­
graphs refers only to standard chambers. C ham ­
bers used on rear brakes only on conventional 80
Series are covered under the separate heading of
“ Stopmaster Brakes.” Chambers used as op­
tional equipment for air operated emergency and
parking brakes are covered under separate head­
ing of “ DD3 Brake Actuator System.” Chambers
on rear brakes of series 70 and 80 tilt models,
and for front brakes are covered here.
CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L