Pontiac FIREBIRD 1972 Service Manual page 109

1A-50 1972 PONTIAC SERVICE MANUAL
pump until gauge shows 28-29" vacuum. (NOTE: In
all evacuating procedures specification of 28-29 in-
ches of vacuum is used. This evacuation can only be
attained at or near sea level. For each 1000 feet above
sea level where this operation is being performed,
specification should be lowered by one inch of mer-
cury vacuum. At 5000 feet elevation only 23" to 24"
of vacuum can normally be obtained.)
If vacuum cannot be pulled to the minimum specifi-
cation for the respective altitude, it indicates a leak
in the system or gauge connections or a defective
vacuum pump. In this case, it will be necessary to
check for leaks as described under LEAK TESTING
THE REFRIGERANT SYSTEM.
6. When specified vacuum level (28-29 inches at sea
level) is obtained, continue to run vacuum pump for
ten additional minutes. During these ten minutes:
a. Prepare for charging the system. If using a charg-
ing station, fill charging cylinder. If using mani-
fold gauge set, make all preparations for charging
system as described under DISPOSABLE CAN
METHOD or REFRIGERANT DRUM
METHOD.
b. Measure oil loss collected as a result of rapid
discharge.
c. Uncap 524095 compressor oil injector (Fig. 1A-
47A) and open valve. Flush tool with refrigerant,
close valve and insert pick-up tube into graduated
container of clean refrigerant oil.
d. Connect 524095 to suction fitting at P.O.A. valve.
(Note: When valve on tool is opened, the vacuum
applied to the discharge side of the system will
suck oil into system from container. Therefore,
close observation of oil level in the container is
necessary .)
e. Note level of oil in container. Open valve on oil-
adding tool until oil level in container is reduced
by an amount equal to that lost during discharge
of system, then shut valve. Take care not to add
more oil than was lost.
f. Disconnect oil injector and connect pick-up tube
to injection fitting to protect tool from moisture
and foreign material.
7. Turn hand shut-off valves at low and high pressure
gauges of gauge set to full clockwise position with
vacuum pump operating, then stop pump. Carefully
check low pressure gauge for two minutes to see that
vacuum remains constant. If vacuum reduces, it indi-
cates a leak in the system or gauge connections.
LEAK TESTING THE REFRIGERANT
SYSTEM
After evacuating the complete system, leak test the system
as follows:
1. Turn hand shut-off valves at low and high pressure
gauges of gauge set to the full clockwise position with
the vacuum pump operating; then stop pump.
2. Connect flexible line from center fitting of the gauge
set to refrigerant drum (drum should be at room
temperature).
3. Open shut-off valve on drum and loosen flexible line
fitting at center fitting of gauge set so that refrigerant
will purge all air from line. Tighten flexible line fit-
ting when certain all air has been purged from line.
CONNECT PICK-UP TUBE F I T T I N G
I
T O P.O.A. V A L V E F I T T I N G WHEN
O I L INJECTOR IS NOT I N USE
PICK-UP
SHUT-OFF
VALVE
T O P.O.A. V A L V E
SUCTION FITTING
Fig. 1A-47A J - 2 4 0 9 5 Compressor Oil Injector