Leak Testing - GMC 1989 Light Duty Truck Repair Manual

1B3-14 R-4 AIR CONDITIONING COMPRESSOR
Tools Required:
J 9625-A Pressure Test Set
J 5420 Straight Fitting
J 25008-A Holding Fixture
J 23500-01 Portable Charging Station
1. Install J 9625 on the rear head of the compressor.
2. Attach the center hose of the manifold gage set on the
charging station to a refrigerant drum standing in an
upright position and open the valve on the drum.
3. Connect the charging station high and low pressure
lines to corresponding fittings on J 9625-A, using
J 5420 if hoses are not equipped with valve depre­
ssors.
• Suction port (low-side) of the compressor has a
large internal opening. The discharge port (hi-
side) has a sm aller internal opening into the
compressor.
4. Open the low-pressure control, high-pressure control
and refrigerant control on the charging station to
allow refrigerant vapor to flow into the compressor.
5. Using a leak detector, check for leaks at the pressure
relief valve, compressor shell to cylinder, compressor
front head seal, and com pressor shaft seal. After
checking, shut off the low pressure control and high
pressure control on the charging station.
6. If an external leak is present, perform the necessary
corrective measures and recheck for leaks to make
certain the leak has been corrected.
7. Loosen the m an ifold gage hose co n n e ctio n s to
J 5420 connected to the low and high sides and allow
the vapor pressure to release from the compressor.
8. Disconnect J 5420 from J 9625-A.
9. Rotate the complete com pressor assembly (not the
crankshaft or drive plate hub) slowly several turns to
distribute oil to all cylinder and piston areas.
10. Install a shaft nut on the compressor crankshaft if the
drive plate and clutch assembly are not installed.
11. Using a box-end wrench or socket and handle, rotate
the compressor crankshaft or clutch drive plate on the
crankshaft several turns to ensure piston assembly to
cylinder wall lubrication.

LEAK TESTING

12. Connect the charging station high pressure line or a
high pressure gage and J 5420 to J 9625-A high side
connector.
13. Attach J 5420 to the suction or low pressure port of
J 9625-A to open the Schrader-type valve.
Oil will drain out of the com pressor suction port
adapter if the compressor is positioned with the suc­
tion port downward.
14. Attach the compressor to J 25008-A using metric
mounting screws. Clamp the com pressor holding fix­
ture in a vise so that the com pressor can be manually
turned with a wrench.
15. Using a wrench, rotate the com pressor crankshaft or
drive plate hub 10 complete revolutions at a speed of
approximately one-revolution per second.
Turning the compressor at less than one-revolution
per second can result in a lower pump-up pressure
and disqualify a good pum ping compressor.
16. Observe the reading on HIGH pressure gage at the
completion of the tenth revolution of the compressor.
The pressure reading for a good pum ping com pres­
sor should be 344.75 kPa (50 psi) or above. A pres­
sure reading of less than 310.275 kPa (45 psi) would
indicate one or more suction and/or discharge valves
leaking, an internal leak or an inoperative valve, and
th e c o m p re s s o r s h o u ld be d is a s s e m b le d and
checked for cause of leak. Repair as needed, re­
assemble and repeat the pump-up test. Externally
leak test.
17. W hen the p ressure pum p-up te st is co m p le te d,
release the air pressure from the HIGH side and
remove J 5420 and J 9625-A.
18. On the R-4 compressor, tilt the com pressor so that
the com pressor suction and discharge ports are
down. Drain the oil from the compressor.
19. Allow the compressor to drain for 10 minutes, then
charge with the proper amount of oil. The oil may be
poured into the suction port.
If further assembly or processing is required, a ship­
ping plate or J 9625-A should be installed to keep out
air, dirt and moisture until the com pressor is installed.