Pontiac tempest 1968 Service Manual page 31

1A-4
1968 P O N T I A C SERVICE M A N U A L
check for leaks as outlined below, after a small
amount of Refrigerant-12 has been added to the low
side of the system*
a. Turn hand shut-off valves at the low and high
pressure gauge of the gauge set to full clockwise
position with the vacuum pump operating, then
stop pump.
b. Connect flexible line from center fitting of
the gauge set to refrigerant drum (drum should be
at room temperature).
NOTE: It may be necessary to use reducer
J 5462-4 with washer J 5462-9 to attach flexible
hose to refrigerant drum.
c. Open shut-off valve on drum and loosen
flexible line fitting at center fitting at gauge set
so that refrigerant w i l l purge a l l air from line.
Tighten flexible fitting when certain a l l air has
been purged from line.
d. Open suction valve on gauge set. This w i l l
allow refrigerant to pass from the drum into the
system. When pressure stops rising, close suc­
tion valve on gauge set and valve at refrigerant
drum (as refrigerant drum Is at room tempera­
ture, only a small refrigerant charge w i l l enter
the system),
e. Using leak detector J 6084, check a l l fittings
• i n the system, compressor shaft seal and on gauge
set for evidence of leakage. When general area of
leak has been found with the test torch, a liquid
leak detector may be helpful In locating the exact
point of leakage. After leak has been corrected,
evacuate the system again.
6. Turn the hand shut-off valves at the low and
high pressure gauge of the gauge set to the full
clockwise position with the vacuum pump operating,
then stop pump. Carefully check low pressure gauge
to see that vacuum remains constant. If vacuum
reduces, i t indicates a leak i n the system or gauge
connections. See NOTE In step 5 above for method
of locating leak.
CHARGING THE SYSTEM
The system should be c h a r g e d only after
being evacuated as outlined i n EVACUATING THE
SYSTEM.
REFRIGERANT DRUM METHOD
1. Connect center flexible line of gauge set to
refrigerant drum.
NOTE: It may be necessary to use reducer
J 5462-4 with washer J 5462-3 and fitting J 5462-9
to attach flexible line to refrigerant drum.
2. Place * refrigerant drum i n a pail of water
which has been heated to a maximum of 125°F.
CAUTION: Do not allow temperature of water to
exceed 125 °F. High temperature will cause exces­
sive pressure and possible softening of fusible
safety plugs in the refrigerant drum. It may not be
necessary to use hot water if a large drum is used
(over approximately 100 lbs.).
3. Place refrigerant drum (In pail of water) on
scales (bathroom or commercial, preferably com­
mercial), Fig. 1A-3.
CAUTION: Do not turn refrigerant drum upside
down as this would allow liquid refrigerant to enter
compressor which may cause damage.
4. If line at center gauge fitting has not been
purged of air, loosen line at center fitting on gauge
set and crack valve on refrigerant drum to blow air
from line. Retighten line at center fitting and record
exact weight of refrigerant tank i n water on the
scales.
5. Open valve on refrigerant drum and both valves
on gauge set to allow refrigerant to flow into system.
Continue charging until the scales show that 4 1/8
pounds of refrigerant have been transferred from
refrigerant drum to system for Pontiac or Tempest.
THE FREON CHARGE FOR THE FIREBIRD CUSTOM
AIR CONDITIONING SYSTEM IS 3-3/4 LBS.
NOTE: If full charge cannot be attained, close
both valves on gauge set, start engine, and turn
temperature control knob to full cold position with
NORMAL or A/C button depressed. Open low
pressure valve on gauge set slowly and leave open
until full charge is added.
CAUTION: Observe high pressure gauge while
charging with compressor running. Shut off engine
if pressure exceeds 375 psi. A large fan placed in
front of the car will help reduce excessively high
head pressure.
6. Close both valves on gauge set (high pressure
valve w i l l already by closed i f charging was com­
pleted by running compressor) and close valve on
refrigerant drum.
NOTE: If the engine was used to complete the
Refrigerant-12 charge into the system, close valve
on refrigerant drum to permit compressor to draw
any refrigerant left in the line from the drum to
the center fitting of the gauge set, then close the
low pressure valve on the gauge set.
7. Operate engine at 2000 r p m with temperature
control knob at full cold position and blower control
for high speed with NORMAL or A / C button de­
pressed. After ten minutes of operation observe
appearance of refrigerant in receiver-dehydrator.
If bubbles are observed, open low pressure gauge