Chevrolet 70 1969 Series, Shop Manual

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BRAKES 5A-4
■FRONT
■ FR O N T -
70 CONV.
7
JOl
6
9
lOi
8
“F”
-FRONT
7
“ F”
“ FR3"
70 CONV. TANDEM
70 TILT
'FR3”
‘FR3”
T - 2 9 2 0
Figure 4— Brake Bleeding Sequence Chart
with 40 to 50 psi air pressure.
2. Clean dirt from around master cylinder
filler cap or cover. Remove standard cover and
install special cover required to fit the model cyl­
inder used. Connect pressure tank hose to filler
cap or cover opening. Bleed air from hose before
tightening connection. Open valves at both ends of
hose.
3. First bleed master cylinder valve on models
where used. Slip end of bleeder hose over bleeder
valve No. 1 and place other end in a glass jar con­
taining enough hydraulic fluid to cover end of hose.
Open bleeder valve with wrench and observe flow
of fluid from hose. Close bleeder valve as soon as
bubbles stop and fluid flows in a solid stream.
4. Bleed valve No. 2 (on power cylinder where
used), then bleed wheel cylinders in sequence shown
in figure 4. After bleeding wheel cylinders, repeat
bleeding operations at power cylinder (where used).
5. If, after bleeding, the pedal "feel" is not
satisfactory, it is recommended that the residual
check valve in the master cylinder or the check
valve in the power cylinder piston be inspected (on
those models which have check valves). Improper
operation of either or both of these valves will re­
sult in the same pedal "feel” as air in the system.
Refer to applicable procedures for repair. If these
valves are operating properly, or if "feel" is not
satisfactory on models not using check valves, then
air is still present in system and bleeding again
will be necessary.
M A N U A L B L E E D IN G
Manual bleeding is the same as pressure
bleeding, except that the brake fluid is forced
through the lines by pumping the brake pedal in­
stead of by air pressure. Fluid in master cylinder
must be replenished after bleeding at each valve.
Brake pedal should be pumped up and down slowly,
and should be on downstroke as valve is closed.
CHEVROLET SERIES 70*60 H EAVY DUTY TRUCK SH O P M A N U A L