1A-2
1968
PONTIAC
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
TEMPEST
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 re-
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).
Fig.
1
A-l Pipe and Hose Connection Torque Chart
a.
Close hand shut-off valves on
gauge
set by
turning
clockwise.
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