Rem Oval - GMC 1982 Light Duty Truck Service Manual

A - 6 C O M P R E S S O R P R E S S U R E R E L I E F
V A L V E
W hen necessary to replace the Pressure Relief Valve
located in the com pressor rear head casting (Fig. ID-23),
the valve assembly should be removed after purging the
system of refrigerant. A new valve and O-ring coated with
525 viscosity refrigerant oil should be installed (see
discharging, adding oil, evacuating and charging procedures
for C.C.O .T. A /C systems in the air conditioning section).
D IS C H A R G E S Y S T E M BEFORE
R E M O V I N G H IG H P R E S S U R E
RELIEF V A L V E
HI PR ESS.
RELIEF
V A L V E
Fig. 1D-23 A-6 High Pressure Relief Valve
A - 6 C O M P R E S S O R I N T E R N A L
M E C H A N I S M ( C Y L I N D E R A N D S H A F T
A S M . )
Service operations to the A-6 com pressor R ear H ead
or In ternal M echanism
com pressor should be perform ed with the system purged of
refrigerant according to the discharging, adding oil,
evacuating and charging procedures for C.C.O.T. A /C
systems in the A ir C onditioning section. The com pressor
m ust also be removed from the vehicle to insure th at the
necessary degree of cleanliness
A dditionally, ''Com pressor C lutch Plate and H ub, Pulley
and Bearing, Clutch Coil and H ousing and Shaft Seal"

Rem oval

procedures, as
O V E R H A U L section, all are to have been followed. Clean
hands, clean tools and a clean bench, preferably covered
with clean paper, are of extrem e im portance.
A n inspection should be m ade o f the Internal
M echanism (Cylinder and Shaft) assembly to determ ine if
any service operations should be performed. A detailed
inspection of parts should be m ade to determ ine if it is
necessary to replace them .
Rem oval
1. Before proceeding with disassembly, wipe exterior
surface o f com pressor clean.
2. All oil in com pressor should be drained and
m easured. Assist draining by positioning com pressor with
AIR CONDITIONING COMPRESSOR OVERHAUL 1D-11
REA R H E A D
5 0 4 0
(C ylinder and Shaft) of the
may be m aintained.
described earlier in
oil drain plug down. R ecord the am ount of oil drained from
the com pressor
D istribution" in the A ir Conditioning section).
3. Invert com pressor and Holding Fixture J 9396, with
front end of com pressor shaft up, suction - discharge ports
now facing dow nw ard (Fig. ID-24).
SHELL
HOLDING
FIXTURE
J-9396
Fig. 1D-24 A-6 Compressor Installed in Holding Fixture
A dditional oil may drain from the com pressor at this
time. All oil m ust be drained into a container so that total
am ount can be measured. (SEE STEP 2 ABOVE.) A liquid
m easuring cup may be used for this purpose. D rained oil
should then be discarded.
4. Remove four locknuts from threaded studs on
com pressor shell and remove rear head. T ap uniformly
around rear head if head is binding (Fig. ID-24).
5. Wipe excess oil from all sealing surfaces on rear head
casting webs, and examine sealing surfaces (Fig. ID-25). If
any dam age is observed, the R ear Head should be replaced.
the
S U C TIO N SCREEN
Fig. 1D-25 A-6 Rear Head Removal
6. Remove Suction Screen and examine for any dam age
or contam ination. Clean or replace if necessary.
(See " C.C.O.T. Refrigerant
A LIN G
SURFACES
REAR HEAD
.S H E LL TO H EAD
" 0 " RIN G
O IL P U M P
ROTORS
Oil
204974