14-17. AIR-CONDITIONING SYSTEM SERVICING (R-12) (Cont'd)
g. Checking/Adding Lubricating Oil
It is not necessary to check or add oil as routine maintenance. It is
compressor, or receiver/dryer has been replaced, or there was an
obvious oil leak. When a system is discharged, it is also necessary
to replace any oil carried out with the refrigerant.
Vehicle must be on level ground.
Charge A/C system (refer to task f.).
Make sure low pressure gauge valve (1) and high pressure gauge valve (2) on manifold gauge set (3)
are turned clockwise to off position.
Turn two service valve shafts (6) counterclockwise to back-seated position.
Start engine and turn on A/C system (refer to TM 9-2320-280-10). Allow engine to idle for
approximately ten to fifteen minutes. Stop engine.
Turn two service valve shafts (6) clockwise to front-seated position.
Do not allow refrigerant R-12 to escape too quickly. Lubricating oil
When high pressure gauge and low pressure gauge read "zero",
the compressor is discharged.
Turn low pressure gauge valve (1) and high pressure gauge valve (2) counterclockwise slightly to
permit refrigerant in the compressor (5) to slowly escape through center hose (4) until gauges
Close low pressure gauge valve (1) and high pressure gauge valve (2).
Remove fill plug (7) and O-ring (8) from compressor (5). Discard O-ring (8).
Look through fill plug (7) hole in compressor (5) and rotate front clutch plate (9) with ratchet and
socket to position internal compressor parts, as shown. Planet plate should be positioned so that
dipstick can be inserted to full depth.
Insert the dipstick to its stop position, as shown. The stop is the angle near the top of the dipstick.
The point of the angle must be to the right, and the bottom surface of the angle must be flush with
the surface of the filler hole.
Remove dipstick from compressor (5) and count number of increments oil level is up to on dipstick.
Oil level should be between six and eight increments on dipstick. Add or subtract oil as necessary to
attain proper level.
Lubricate O-ring (8) with lubricating oil and install O-ring (8) and fill plug (7) on compressor (5).
Tighten fill plug (7) to 6-9 lb-ft (8-12 Nm).
Remove manifold gauge set (refer to task b.).
SERVICE VALVE IN
SERVICE VALVE IN