Chevrolet Light Duty Truck 1973 Service Manual page 100

1A-74 HEATER A N D AIR C O N D IT IO N IN G
VALVES
Fig. 89--Expansion Valves (G Overhead System)
Before removing the lower case
W ARNING:
screws, support the case to prevent damage to
the case or motor assemblies.
4. Disconnect the center ground wire and the blower
motor lead wires. Remove the lower to upper case
screws and lower the lower case and blower motor
assemblies.
5. Disconnect the valve sensing bulb from the core
outlet line.
6. Disconnect the core inlet and outlet lines and
remove the valve assembly. Cap or plug the open
connections at once.
installation (Inner Valve)
1. Remove caps or plugs from system connections and
install the new valve assembly using new "O " rings
coated with clean refrigeration oil.
2. Install the sensing bulb, making sure that the bulb
makes good contact with the core outlet line.
3. Install the lower case and blower motor assemblies.
4. Install the rear shroud as outlined previously.
5. Connect the battery ground cable and compressor
clutch connector.
6. Evacuate, charge and check the system.
Removal (Outer Valve)
1. Disconnect the battery ground cable and compres­
sor clutch connector.
2. Purge the system of refrigerant.
3. Remove the rear shroud as outlined previously.
4. Disconnect the blower motor ground straps and
leads.
5. Disconnect the refrigerant lines at the rear of the
blower-evaporator assembly. Cap or plug all open
connections at once.
6. Remove the blower-evaporator to roof panel
7. Remove the lower to upper case screws and remove
VALVE SENSING
BULBS
8. Remove the expansion valve bulb from the
Installation (Outer Valve)
1. Remove the caps or plugs from the refrigerant
2. Install the upper case to the core making sure the
3. Install the lower case and blower assemblies.
4. Install the blower-evaporator to the roof panel.
5. Connect the refrigerant lines at the rear of the
6. Connect the blower lead wires and ground straps.
7. Install the rear shroud as described previously.
8. Connect the battery ground cable and the
9. Evacuate, charge and check the system.
SUPPORT
EVAP &
BLOWER ASM
BLOWER M O TO R
GRD WIRES
attachm ents and lower the blower-evaporator
assembly. Remove the assembly and place on a
work bench upside down.
the lower case assembly. Remove the upper shroud
from the upper case and then remove the upper
case from the core.
evaporator outlet line. Remove the expansion valve
inlet and outlet lines and cap or plug the open
connections at once. Remove the valve.
connections and install the new valve using new
"O " rings coated with clean refrigeration oil. Install
the sensing bulb, making sure that the bulb makes
good contact with the core outlet line.
sealing strips are positioned correctly. Install the
upper shroud on the upper case.
blower-evaporator unit using new "O " rings coated
with clean refrigeration oil.
compressor clutch connector.
Fig. 90-Blower-Evaporator (G Overhead System)
B O W
SUPPORT
BRACKET
LIGHT DUTY TRUCK SERVICE MANUAL