Vacuum Motor Replacement; Sensor Replacement - GMC 1976 ZEO 6083 Maintenance Manual

Figure 5-Checking Sensor
SPECIFICATIONS FOR DAMPER
OPERATION
Temperature :
79 degrees F . (26 .1°C .) or lower,
damper fully closed .
123 degrees F . (50 .6°C .) or higher,
damper fully open .
Vacuum :
3 in . hg . of vacuum or lower,
damper fully open below 79
degrees F . (26 .1°C .)
7 in . hg . of vacuum or higher,
damper fully closed below 79
degrees F . (26 .1°C .)
1. If temperature is within specifications, Con-
trolled Combustion System is functioning properly .
2. If temperature is out of specifications and
vacuum is correct, replace sensor.
3. If both temperature and vacuum are within
specifications and damper is not operating correctly,
replace vacuum motor.
4. If both temperature and vacuum are not within
specifications it is an indication that the vacuum
motor diaphragm is leaking.
VACUUM MOTOR REPLACEMENT
REMOVAL
1 . Remove air cleaner.
2. Disconnect vacuum hose from motor .
3. Drill out the two spot welds initially with a
1/16" drill, then enlarge as required to remove the
EMISSION CONTROL SYSTEMS
6T- 5
retaining strap. Do not damage the snorkel tube (See
figure 6.) .
4. Remove motor retaining strap.
5 . Lift up motor, cocking it to one side to unhook
the motor linkage at the control damper assembly.
INSTALLATION
1 . Drill a 7/64" hole in snorkel tube at point "A"
as shown in Figure 6.
2. Insert vacuum motor linkage into control
damper assembly .
3. Use the motor retaining strap and sheet metal
screw provided in the motor service package to se-
cure the retaining strap and motor to the snorkel
tube .
4. Make sure the screw does not interfere with the
operation of the damper assembly . Shorten screw if
required .
5. Connect vacuum hose to motor and install air
cleaner.
SENSOR REPLACEMENT
REMOVAL
1 . Remove air cleaner.
Figure 6-Air Cleaner Spot Welds