Temperature Sensor Replacement; Vacuum Motor Replacement - Chevrolet 10 1971 Series Chassis Service Manual

Fig. 9A — Checking Vacuum Diaphragm
4. If damper door does not close completely or does
not open at correct temperature, continue with the
following vacuum motor check:
a. Turn off engine. Disconnect diaphragm assembly
vacuum hose at sensor unit.
b. Apply at least 9 in. Hg. of vacuum to diaphragm
assembly through the hose. This can be done by
mouth. Damper door should completely close
snorkel passage when vacuum is applied. If not
check to see if linkage is hooked up correctly
and for a vacuum leak.
c. With vacuum applied, bend or clamp hose to trap
vacuum in diaphragm assembly (fig. 9a).
Damper door should remain in position (closed
snorkel passage). If it does not, there is a vac­
uum leak in diaphragm assembly. Replace dia­
phragm assembly.
5. If vacuum motor check is found satisfactory, replace
sensor unit.
V A C U U M M OTO R REPLACEMENT
Removal
1. Remove air cleaner from engine.
2. Drill out spot welds fastening vacuum motor re­
taining strap to snorkel tube.
3. Remove vacuum motor by lifting and unhooking
linkage rod from damper door.
Replacement
1. Drill 7/64" hole in snorkel tube at center of vacuum
motor retaining strap (fig. 10a).
2. Connect vacuum motor linkage to damper door.
Fasten retaining strap to air cleaner with sheet
metal screw.
3. Replace air cleaner on engine and check operation
of vacuum motor and control damper assembly.
DRILL 7 / 6 4 " HOLE
IN CENTER P O SIT IO N
OF STRAP
SPOTW ELDS
V A C U U M D IA P H R A G M
R ET A IN IN G STRAP
Fig. 10A— Vacuum Diaphragm Replacement

TEMPERATURE SENSOR REPLACEMENT

Removal
1. Remove air cleaner from engine and disconnect
vacuum hoses at sensor.
2. Pry up tabs of sensor retaining clip (fig. 11a).
Observe position of sensor, new sensor
NOTE:
must be installed in this same position.
3. Remove clip and sensor from air cleaner.
Replacement
1. Install sensor and gasket assembly in air cleaner
in position as noted above.
2. Press retaining clip on sensor. Support the sensor
on its side to prevent damage to the control mech­
anism in the center.
3. Install air cleaner on engine and connect vacuum
hoses.
1 1
Fig. A — Removing Sensor Unit
ENGINE FUEL 6M-21
INSTALL REPLACEMENT
S E N S O R A S S M . IN S A M E
P O SIT IO N A S O R IG IN A L A SS M .
10-30 CHEVROLET TRUCK SERVICE MANUAL