Chevrolet Light Duty Truck 1973 Service Manual page 92

1A-66 HEATER A N D AIR C O N D IT IO N IN G
Fig. 73 -Blower Motor (C-K Overhead System)
not contact the case and then tighten the wheel
setscrews.
4. Place the lower case and blower motor assembly in
position in the vehicle and install the lower to upper
case screws.
NOTE: Rotate the blower wheels to make
sure that they do not rub on the case.
5. Install the center ground wire and connect the
blower lead wire.
6. Install the rear duct assembly as described
previously.
7. Connect the battery ground cable.
EXPANSION VALVE
This system incorporates an expansion valve which does
not utilize an external equalizer line (fig. 74).
Removal
1. Disconnect the battery ground cable.
2. Purge the system of refrigerant.
3. Remove the rear duct as outlined previously.
4. Disconnect the blower motor lead and ground
wires.
5. Remove the lower to upper blower-evaporator case
screws and lower the lower case and motor
assembly.
Before removing the case screws
CAUTION:
support the lower case and motor assemblies.
6. Remove the expansion valve sensing bulb clamps.
7. Disconnect the valve inlet and outlet lines and
remove the expansion valve assembly. Cap or plug
the open connections at once.
Installation
1. Remove caps or plugs from system connections and
EVAPORATOR
SCREEN
EXPANSION
VALVE
7 4
Fig. -E x p a n s io n V alve
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.
Connect the blower motor lead and ground wires.
4. Install the rear duct as outlined previously.
5. Connect the battery ground cable.
6. Evacuate, charge and check the system.
EVAPORATOR CORE (Fig. 74)
Removal
1. Disconnect the battery ground cable.
2. Purge the system or refrigerant.
3. Remove the rear duct as outlined previously.
4. Disconnect the blower motor lead and ground wire
connections.
5. Disconnect the refrigerant lines at the rear of the
blower-evaporator assembly. Cap or plug the open
connections at once.
6. Remove the blower-evaporator to roof panel
support nuts and washers, lower the blower-
evaporator assembly and place it on a work bench
upside down.
Remove the lower to upper case screws and remove
7
.
the lower case assembly. Remove the upper case
from the evaporator core.
8. Remove the expansion valve inlet and outlet lines
and cap or plug the open connections at once.
Remove the expansion valve capillary bulb from
,
the evaporator outlet line and remove the valve.
9. Remove the plastic pins holding the screen to the
core and remove the screen.
Installation
1. Install the wire screen to the front of the core and
insert the plastic pins.
2. Install the expansion valve inlet and outlet lines
BLOWER-EVAPORATOR
UPPER CASE
EVAPORATOR
CORE SENSING BULB
(C-K
O v e rh e a d S y s te m )
LIGHT DUTY TRUCK SERVICE MANUAL