Chevrolet 70 1969 Series, Shop Manual

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TRANSMISSIONS AND CLUTCHES 7A -10
a. Gas Engine Models - Pull secondary wire
out of center socket in distributor cap and ground
wire to prevent possible damage to coil.
b. Diesel Engine Models - Place fuel shut-
off lever in SHU T- O FF position.
2. Move selector lever (B) to “ N ” (Neutral)
position, then referring to Inset, Fig. 10, loosen
jam nuts and adjust length of push rod to di­
mension shown.
3. With neutral safety switch push rod
properly adjusted, tighten jam nuts securely.
4. Check each range position of shift linkage
to make sure the starter does not operate with
the selector lever in any position other than “ N ” .
If necessary readjust switch.
5. Reconnect secondary wire to distributor
cap, on gas engine models.
RETARDER ADJUSTMENT
The transmission retarder on truck models
covered by this manual are activated by hydraulic
controls.
C O N V E N T IO N A L C A B
N O T E : Conventional cab models refer to Fig­
ure 11.
1. Loosen lock nut on master cylinder push
rod assembly, then turn hex portion of push rod
(fig. 12) as necessary to provide 0 to 1/1 6-inch
clearance between push rod and master cylinder
piston. After making adjustment, tighten lock nut
on push rod.
IM P O R T A N T : Make sure piston contacts snap
ring in master cylinder bore when pedal is releas­
ed. Install boot on master cylinder.
2. With retarder hydraulic system bled, de­
press the retarder pedal until the retarder valve
on the transmission is fully engaged ("O N " posi­
tion).
3. Holding the retarder pedal in the " O N ”
position, adjust the pedal stop bracket at " A "
(Conv. Cab Models) until it touches the pedal as
shown. Tighten steering pivot bolt ” C ” to 8-10
foot-pounds torque (Conv. Cab Models, only).
N O T E : Full travel of retarder valve from
" O F F " to " O N " position is ^-inch.
4. Have an assistant depress retarder pedal
(in cab) while checking for proper movement of
retarder valve. Use a scale to be sure movement
of valve from " O F F " to " O N ” position is l A-inch.
5. Have assistant release retarder pedal. The
retarder valve must return to the " O F F " position
(retarder valve fully closed) when the pedal is
released. The pedal must return positively and
immediately to released position (pedal against
bumper stop " B " ) when foot pressure is released.
6. Readjust linkage, if necessary.
M O D E L S T M 8 0 (Fig. 13)
1. With retarder hydraulic system bled, de­
press the retarder pedal until the retarder valve
on the transmission is fully engaged ("O N " position).
2. Holding the retarder pedal in this position
adjust the stop bolt " A " until it touches pedal as
shown. Release the pedal and tighten lock nut
against master cylinder.
N O T E : Full travel of retarder valve from
" O F F ” to " O N ” position is J^-inch.
3. Have assistant release retarder pedal. The
retarder valve must return to the " O F F " position
(retarder valve fully closed) when the pedal is re­
leased. The pedal must return positively and im­
mediately to released or " O F F ” position when foot
pressure is released.
4. Readjust stop bolt, if necessary.
Figure 13— Ref order Controls ITM 80!
CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L