GMC 1976 ZEO 6083 Maintenance Manual page 85

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AIR CONDITIONING SYSTEM
5 . Remove the compressor from mounting and
remove the oil test fitting.
6. Pour out the oil into a clean glass container
and examine it for any foreign substance such as dirt,
water, metal particles, etc. If any of these are present,
the compressor, expansion tube, and accumulator or
receiver-dehydrator should be replaced and the other
system components should be flushed with liquid
refrigerant .
7. If the oil is clean and free of any harmful
substance, replace oil with Frigidaire 525 Viscosity
Oil, or equivalent .
NOTE : If the system components have been re-
placed or flushed, replace the full charge of oil.
If not, add no more fresh oil than was drained
in Step 6.
8. Charge up the compressor to cylinder or can
pressure . Leak test the compressor seals prior to in-
stallation of compressor .
9. Reinstall the compressor and evacuate the sys-
tem by following the Evacuating Procedure.
10 . Introduce R-12 vapor at cylinder (room) tem-
perature and pressure .
11 . Leak test all fittings and connections and give
particular attention to a leak test at the compressor
shaft seal if compressor has not been leak tested on
the bench.
12 . Complete system processing and charge sys-
tem.
CONDENSER
REPLACEMENT
1 . Disconnect battery ground cables .
2. Purge the system of refrigerant .
3. Remove grill assembly .
4. Disconnect the condenser inlet and outlet
lines . Cap or plug all open connections at once .
5. Remove the receiver-dehydrator (Type 1) and
its holding straps (See figure 13). '
6. Remove the condenser to radiator mounting
screws (figure 34).
7. Remove the condenser assembly by pulling it
forward and then lowering it from the vehicle
through grille .
Figure 34-Condenser Mounting, Typical
8. To install a new condenser, reverse Steps 1-6
above. Add one fluid ounce of clean refrigeration oil
to a new condenser.
NOTE : Use new"O" rings, coated with clean re-
frigeration oil, when connecting all refrigerant
lines.
9. Evacuate, charge and check the system .
RECEIVER-DEHYDRATOR
REPLACEMENT
1 . Disconnect the inlet and outlet lines being sure
to use a wrench on the square portion of the receiver
Figure 35-Disconnecting Lines to
Receiver-Dehydrator, Type 1