Pontiac tempest 1968 Service Manual page 29

1A-2
1968 P O N T I A C SERVICE MANUAL
assembling joint, as this oil will help in making a
leak-proof-joint.
When tightening joints, use another wrench to hold
stationary part of the connection, so that a solid
feel can be attained, which will indicate proper
assembly.
CAUTION: Tighten all tubing connections as
shown in Fig. 1A-1. Insufficient torque when
tightening can result in loose joints and excessive
torque when tightening can result in deformed
joint parts, either condition can result in refriger­
ation leakage.
5. Do not connect receiver dehydrator indicator
assembly until all other sealed sub-assemblies have
been connected. This is necessary to insure optimum
dehydration and maximum moisture protection of the
refrigeration system.
CAUTION-LIQUID INDICATOR
PONTIAC AND T E M P E S T
Under normal conditions, receiver-dehydrator will
show clear with about 3-1/2 pounds of refrigerant
in the system. However, the air conditioner will
not produce its best performance until 4-1/8 pounds
of refrigerant are in the system. Do not overcharge
with refrigerant, as this will result in extremely
high head pressures and the compressor safety valve
will blow.
FIREBIRD
Under normal conditions, liquid indicator will show
clear with about 2-3/4 pounds of refrigerant in the
system. However, the air conditioner will not pro­
duce its best performance until 3-3/4 pounds of r e ­
frigerant are in the system. Do not overcharge with
refrigerant, as this will result in extremely high
head pressures and the compressor safety valve
will blow.
DEPRESSURIZING THE SYSTEM
1. Remove caps from suction gauge fitting on
Metal Tube
Outside
Diameter
Thread and
Fitting Side
Steel Tubing
Torque
Lb.-Ft.
Aluminum or
Copper
Tubing
Torque
Lb.-Ft.
Nominal
Torque
Wrench Span
%
Vic,
10-15 5-7 5
/8
Vs Vs
30-35 11-13
Va
v%
Va
30-35
11-13
v%
30-35 18-21
iVio
Va 30-35 23-28 Wa
If a connection is made with steel to aluminum or
copper, use torques for aluminum. In other words,
use the lower torque specification.
P.O.A. valve and discharge valve gauge fitting on
compressor.
2. With both valves on manifold gauge set J 5725-
01 closed (clockwise), attach manifold to P.O.A.
valve and compressor, using J 5420 Schrader valve
adapter at suction gauge fitting and J 6163 Schrader
valve adapter at discharge gauge fitting.
3. Crack open high pressure valve on manifold
gauge set to allow slow escape of refrigerant from
system through the manifold gauge set and out center
fitting and hose. (Place end of hose in clean con­
tainer.) If oil drips from hose into the container,
refrigerant is escaping too rapidly.
4. When hissing ceases (indicating all refrigerant
has escaped) close high pressure valve on manifold
gauge set by turning valve clockwise.
EVACUATING THE SYSTEM
When refrigeration system is depressurized and
opened for service, some air will enter lines re­
gardless of how quickly openings are capped. In
order to remove this air and as much as possible
of the moisture it contains, the complete system
must be evacuated. Evacuating is merely the proc­
ess of removing all air from the system, thereby
creating a vacuum in the system.
CA UTION: Under no circumstances should alco­
hol be used in the system in an attempt to remove
moisture, regardless of the successful use of alco­
hol in other refrigeration systems.
PREPARATIONS FOR EVACUATING
COMPLETE SYSTEM
1. Check the low pressure gauge for proper cali­
bration, with the gauge disconnected from the re­
frigeration system. Be sure that the pointer on the
gauge indicates to the center of O. Tap gauge a few
times lightly to be sure pointer is not sticking. If
necessary, calibrate as follows:
a. Remove cover from gauge.
b. Holding gauge pointer adjusting screw firmly
with one hand, carefully force pointer in the proper
direction in proper amount to position pointer
through the center of O position. Tap gauge a few
times to be sure pointer on gauge is not sticking.
Replace gauge cover.
2. If gauge set is not already connected to P.O.A.
valve and compressor, connect as follows (Fig.
1A-2).
F i g . 1 A - l Pipe and Hose Connection Torque Chart
a. Close hand shut-off valves on gauge set by
turning clockwise.