Chevrolet Light Duty Truck 1973, Service Manual

Page: 94 / 979

1A-68 HEATER A N D AIR C O N D I T I O N I N G
9. To install, reverse Steps l-8 above. Add l fluid
ounce of clean refrigeration oil to a new condenser.
CAU TIO N :
Use new "O" rings, coated with
clean refrigeration oil, when connecting all
refrigerant lines.
10. Evacuate, charge and check the system.
RECEIVER-DEHYDRATOR
Replacement (Fig. 76)
1. Disconnect the battery ground cable, and the
compressor clutch connector.
2. Purge the system of refrigerant.
3. Remove the screws that retain the headlight
mouldings and the screws for the grille. Remove the
mouldings and remove the grille.
4. Disconnect the receiver-dehydrator inlet and outlet
lines and cap or plug the connections at once.
5. Remove the receiver-dehydrator bracket attaching
screws.
6. Remove the receiver-dehydrator from the vehicle.
7. If a new receiver-dehydrator is being installed, add
1 fluid ounce of clean refrigeration oil to the new
unit.
8. Connect the inlet and outlet lines using new "O"
rings coated with clean refrigeration oil.
CAU TIO N :
Do not uncap the new unit until
ready to fasten the inlet and outlet lines to the
unit.
9. Install receiver-dehydrator by reversing Steps 1-6
above.
10. Evacuate, charge and check the system.
SIGHT GLASS REPLACEMENT
If damage to the sight glass should occur, a new sight
glass kit should be installed. The kit contains the sight
glass, seal and retainer. (See Figure 77).
1. Purge system.
2. Remove the sight glass retainer nut using a
screwdriver and remove old glass and "O" ring
seal.
3. Install the new glass and seal and retainer nut,
being careful not to turn the nut past the face of
the housing. To do so may damage the "O " ring
seal.
4. Evacuate, charge and check the system.
AIR DISTRIBUTOR DUCT ASSEMBLY
Replacement (Fig. 78)
1. Remove four screws that hold the duct to the engine
cover.
2. Lift upward and rearward on the top of the
distributor duct assembly and move it away from
the evaporator and blower motor assembly cover,
being careful not to damage the seal.
3. To reinstall, reverse Steps 1 and 2, making sure seal
to evaporator and blower motor cover is properly
positioned.
BLOWER-EVAPORATOR COVER
Replacement
(Fig.
78)
1. Remove four screws holding the cover to the
evaporator assembly.
2. Remove the temperature control knob and place the
blower switch on M.
3. Remove the cover being careful not to damage the
seal to the air distributor duct.
4. To reinstall, reverse Steps 1-3, being sure seal to air
distributor duct is properly positioned.
BLOWER-EVAPORATOR ASSEMBLY
Removal
(Fig.
79)
1. Disconnect battery ground cable, and compressor
clutch lead from connector.
2. Purge system of refrigerant.
3. Remove the blower-evaporator cover as described
previously.
4. Disconnect inlet and outlet refrigerant lines from
underneath the unit, and cap or plug the
connections at once.
5. Disconnect drain tubes from evaporator case.
6. Remove blower-evaporator assembly bracket bolts.
7. Remove electrical connections from switches,
resistors, relays and blower motor.
8. To install reverse Steps 1-7 above. Make all
refrigerant line connections using new "O " rings,
coated with clean refrigeration oil.
9. Evacuate, charge and check the system.
EXPANSION VALVE and/or EVAPORATOR
CORE
Replacement
1. Remove the blower-evaporator as described
previously.
2. Remove the cover plate and separate upper and
lower case halves.
3. Disconnect inlet and outlet lines from the
expansion valve. Cap or plug all open connections
at once. Remove sensing bulb from the evaporator
outlet manifold. Remove expansion valve.
LIGHT DUTY TRUCK SERVICE MANUAL