Chevrolet 70 1969 Series, Shop Manual

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CAB A N D BO DY M O U N T IN G S 1-78
from the original oil charge of 11 ozs., to obtain
"oil loss.” Take the new compressor assembly
and drain from it the amount of "oil loss" above;
provided the refrigeration system shows no evi­
dence of a major leak, indicating that little or no
oil has been lost from the system. (Minor leak in­
dicating very slow leakage.)
3. If oil drained in step 1 previously contains
any foreign material such as chips, or there is
evidence of moisture in the system, replace the
receiver-dehydrator assembly and flush all com ­
ponent parts, or replace if necessary. After flush­
ing refrigeration system in this manner, the full
oil charge should be left in the new service com­
pressor or 11 ozs., installed in an overhauled or
repaired compressor.
C O M P R E S S O R R E M O V A L
1. Connect the high and low pressure gauge
lines from the gauge set to the respective connec­
tions on the old compressor on the vehicle. Be
sure valves on gauge set are fully clockwise to
close gauge set to center fitting, and that a J-5420
or J-9459 Schrader adapter is between low pressure
hose and suction gauge fitting, and also at the dis­
charge gauge fitting.
2. Remove the flare nut from center connec­
tion on gauge manifold or the plug in the gauge line
attached to the center connection. Wrap the line at
the outlet with a cloth to protect persons and ve­
hicle surfaces from oil or refrigerant.
3. Slowly depressurize refrigeration system
as instructed previously under "Depressurizing The
System."
4. While system is depressurizing, remove (if
desired) clutch assembly and coil from old com ­
pressor. If parts are not oil soaked and are in
good condition, lay them aside on a clean surface
as they may be installed on the new compressor.
5. After the system is completely depressur­
ized, very slowly loosen screw which retains com ­
pressor fittings assembly to compressor (see fig.
16). As screw is being loosened, work fittings as­
sembly back and forth to break seal and carefully
bleed off any remaining pressure.
C A U T IO N : High pressure may still
exist at the discharge fitting. If this
pressure is released too rapidly there
will be a considerable discharge of re­
frigerant and oil.
6. When all pressure has been relieved, re­
move fittings assembly and O-ring seals.
7. Immediately cover compressor openings.
A simple way is with a plate (similar to the one on
new compressor) which can be attached with fittings
assembly screw, using the O-rings to provide a
seal. See lower portion of figure 16.
Figure 16 — Compressor Fittings Installation
8. Disconnect compressor clutch coil wire and
remove compressor mounting plates to bracket
bolts, front and rear.
9. If there is any possibility that broken parts
from the compressor got into the discharge line or
the condenser, all refrigeration system parts
should be cleaned and a new receiver-dehydrator
assembly should be installed.
10. Drain all oil from compressor just remov­
ed in a clean dry container and replace compressor
drain plug screw. Measure amount of oil drained.
See "Checking Compressor Oil Level and Adding
Oil" previously.
C O M P R E S S O R IN S T A L L A T IO N
N O T E : Before installing a new compressor,
rotate compressor shaft four or five times. This
permits proper lubrication of compressor seal
over all its surface. Before compressor clutch is
mounted to the new compressor, wipe the front
face of the compressor thoroughly with a clean dry
cloth and, if necessary, clean front of compressor
CHEVROLET SERIES 70 -80 H EAVY DUTY TRUCK SH O P M A N U A L