GMC 1982 Light Duty Truck Service Manual page 84

E V A P O R A T O R
SCREEN
E X P A N S IO N E V A P O R A T O R
V A LVE CORE
Fig. 1 B-40--Expansion Valve
2. Install the blower m otor retaining strap and foam.
3. Place the blower motor and wheel assembly into the
lower case. Align the blower wheels so th at they do not
contact the case.
4. Place the lower case and blower motor assembly in
position in the vehicle and install the lower to upper
case screws.
NOTICE: 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 assem bly as described previously.
7. C onnect the battery ground cable.
E X P A N S IO N V A LVE
This sytem incorporates an expansion valve which does
not utilize and external equalizer line (Fig. 1 B-40).
Rem oval
1. Disconnect 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 blow er-evaporator case
screws and lower the lower case and motor assembly.
NOTICE: Before removing the case screws, support the
lower case and motor assemblies to prevent dam age to
the case or motor assemblies.
6. Remove the expansion valve sensing bulb clamps.
7. Disconnect the valve inlet and outlet lines and remove
the expansion valve assembly. C ap or plug the open
connections at once.
Installation
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, m aking sure th at the bulb
m akes good contact with the core outlet line.
3. Install the lower case and blower m otor assemblies.
C onnect 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.
B L O W E R -E V A P O R A T O R
UPPER CASE
S E N S IN G BULB
C 69
System
EVAPO RATO R CORE (Fig. IB -4 0 )
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. D isconnect the refrig eran t lines at the re ar of the
blow er-evaporator assem bly. C ap or plug the open
connections at once.
6. Remove the blow er-evaporator support to roof rail
screw s, lower the blow er-evaporator assem bly and
place it on a work bench upside down.
7. Remove the lower to upper case screws and remove the
lower case assembly. Remove the support to upper case
screws and 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 using
new " O " rings coated with clean refrigeration oil.
Install the sensing bulb to the evaporator outlet line as
shown in Fig. 1 B-44; make sure the bulb has good
contact with the line.
Add 3 oz. clean refrigeration oil when installing a new
core.
3. Install the upper case and supports to the core.
4. Install the lower core case and blower assembly.
5. Install the blow er-evaporator assembly to the roof and
install the support to roof rail screws.
6. Connect the refrigerant lines to the blower-evaporator
unit using new " O "
refrigeration oil.
7. Connect the blower lead and ground wires.
8. Install the rear duct as outlined previously.
9. Connect the battery ground cable.
Fig. 1B-41--Blower Switch (C-K Overhead System)
AIR CONDITIONING IB-41
rings coated with clean