Chevrolet 10 1971 Series Chassis Service Manual page 54

HEATER AND AIR CONDITIONING 1A-36
3. Place the two blower motor and wheel assemblies
into the lower case. Align the blower wheels so that
they do not contact the case and then tighten the
wheel set screws.
4. Place the lower case and blower motor assemblies
in position in the vehicle and install the lower to
upper case screws.
Rotate the blower wheels to make sure
NOTE:
that they do not rub on the case.
5. Install the center ground wires and connect the
blower lead wires.
6. Install the rear duct assembly as described pre­
viously.
7. Connect the battery ground cable.
EXPAN SIO N VALVE
This system incorporates two expansion valves. These
valves do not use the external equalizer line (fig. 51).
Removal (Inner Valve)
1. Disconnect the battery ground cable.
2. Purge the system of refrigerant.
3. Remove the rear duct as outlined previously.
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.
Before removing the lower case
CAUTION:
screws, support the case to prevent damage to
the case or motor assemblies.
5. Disconnect the valve sensing bulb from the core out­
let line. See Figure 51.
6. Disconnect the core inlet and outlet lines and remove
the valve assembly.
tions at once.
Installation (Inner Valve)
1. Remove caps or tape 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.
CORRECT
BLADE
A N G L E
LOWER
C A SE HALF
Fig. 5 0 — Blower M otor Installation
Cap or tape the open connec­
VALVES
Fig. 51— Expansion Valve Capillary Bulbs
Install the rear duct as outlined previously.
4 .
5. Connect the battery ground cable.
6. Evacuate, charge and performance test the system.
Removal (Outer Valve)
1. Disconnect the battery ground cable.
2. Purge the system of refrigerant.
3. Remove the rear duct as outlined previously.
Disconnect the blower motor ground straps and leads,
4 .
relay and thermostatic switch wiring harness.
5. Disconnect the refrigerant lines at the rear of the
blower-evaporator assembly.
6. Remove the blower-evaporator to roof panel, attach­
ments and lower the blower-evaporator assembly far
enough to disconnect the resistor wiring harness.
Remove the assembly and place on a work bench
upside down.
7. Remove the lower to upper case screws and remove
the lower case assembly. Remove the upper shroud
from the upper case and then remove the upper case
from the core.
8. Remove the expansion valve bulb from the evaporator
outlet line. Remove the expansion valve inlet and
outlet lines and cap or tape the open connections at
once. Remove the valve.
Installation (Outer Valve)
1. Remove the caps or tape from the refrigerant con­
nections and install the new valve using new "O"
rings coated with clean refrigeration oil.
2. Install the upper case to the core making sure the
sealing strips are positioned correctly.
upper shroud on the upper case.
3. Install the lower case and blower assemblies.
Install the blower-evaporator to the roof panel, first
4 .
connecting the resistor wires.
5. Connect the refrigerant lines at the rear of the
blower-evaporator unit using new "O" rings coated
with clean refrigeration oil.
6. Connect the blower lead wires and ground straps,
thermostatic switch and relay harnesses.
7. Install the rear duct as described previously.
8. Connect the battery ground cable.
9. Evacuate, charge and performance test the system.
VALVE SENSING
BULBS
Install the
10-30 CHEVROLET TRUCK SERVICE MANUAL