Chevrolet Light Duty Truck 1973 Service Manual page 86

1A-60 HEATER A N D AIR C O N D IT IO N IN G
3. Using needle-nose pliers, remove the expansion
tube from the evaporator core inlet line (fig. 60).
4. Remove the expansion tube "O " ring from the core
inlet line.
5. To install, reverse Steps l-4 above.
NOTE: Install the expansion tube using a
new "O " ring, coated with clean refrigeration
oil.
6. Evacuate, charge and check the system.
SELECTOR DUCT AND HEATER CORE
ASSEMBLY
Replacement (Figs. 61 and 62)
1. Disconnect the battery ground cable.
2. Drain the radiator and remove the heater hoses
from the core tubes. Plug the core tubes to prevent
coolant spillage during removal.
3. Remove the glove box and door as an assembly.
4. Remove the center duct to selector duct and
instrument panel screws and remove the center
lower and center upper ducts.
5. Disconnect the bowden cable at the temperature
door.
6. Remove the nuts from the three selector duct studs
projecting through the dash panel.
7. Remove the selector duct to dash panel screw
(inside vehicle).
8. Pull the selector duct assembly rearward until the
core tubes clear the dash panel. Lower the selector
assembly for enough to gain access to all vacuum
and electrical harness.
9. Disconnect the vacuum and electrical harness and
remove the selector duct assembly.
10. Remove the core mounting strap screws and remove
the core.
11. To install, reverse Steps 1-10 above.
12. Refill coolant system and connect the battery
ground strap.
KICK PAD VALVE
(Fig. 63)
Replacement
1. Disconnect the vacuum hose at the actuator.
2. Unhook the valve return spring at the actuator end.
3. Remove the actuator bracket mounting screws.
4. Remove the cam to actuator arm screw and
separate the actuator and bracket from the cam.
5. Remove the actuator to bracket nuts and separate
the actuator and bracket.
6. To install reverse Steps 1-5 above.
PLENUM VALVE
(Fig. 63)
Replacement
1. Raise the hood.
2. Remove the cowl plastic grille.
3. Remove the three cowl to valve assembly screws
and remove the valve assembly from the vehicle.
4. Remove the actuator arm push nut.
5. Remove the actuator to valve nuts and separate the
valve and actuator.
6. To install, reverse Steps 1-5 above.
CONTROL ASSEMBLY
(Fig. 64)
Removal
1. Disconnect the battery ground cable.
2. Remove the radio as outlined in Section 15 of this
manual.
3. Remove the instrument panel bezel.
4. Remove the control to instrum ent panel screws and
lower the control far enough to gain access to the
control assembly.
Be careful not to kink the bowden
CAUTIO N:
cable.
Disconnect the bowden cable, vacuum harness and
electrical harness at the control.
Remove the control through the radio opening.
If a new unit is being installed, transfer all
electrical switches and vacuum valves to the new
control.
LIGHT DUTY TRUCK SERVICE MANUAL