Chevrolet 1977 10 Series, Repair Manual, Page: 28 / 468

1B-22
OVERHAUL MANUAL
SLIGHTLY ROTATE
FRONT HEAD IF
NECESSARY TO
j
LINE UP LOCATOR
PINS AND HOLES I
REAR HEAD
Fig. 6 6 —In sta ll in g Rear Head
R 4 -C 0 MPRESSOR OVERHAUL
GENERAL
When servicing a compressor, it is essential that steps
be taken to prevent dirt or foreign m aterial from getting on
or into com pressor parts and system during disassembly or
reassembly of compressor. Clean tools, a clean workbench
and a clean work area are very im portant for proper service.
The compressor connection
areas and exterior of
compressor should be cleaned off as m uch as possible prior
to any "on vehicle" repairs or removing compressor for
workbench service. The parts must be kept clean at all times
and any parts to be reassembled should be cleaned with
clean solvent (trichlorethylene, or Stoddard solvent) and
dried with dry air. W hen necessary to use a cloth on any
part, it should be of a non-lint producing type. Refer to
Figure 67 for the exploded view of the compressor parts and
nomenclature.
When a compressor is removed from the vehicle for
servicing, the am ount of oil remaining in the compressor
should be drained through compressor suction-discharge
ports and measured. This oil should then be discarded and
new oil added to the compressor before compressor is again
placed in operation on vehicle. Refer to the Diagnosis
Section for compressor oil charge.
If for any reason the R-4 compressor air conditioning
hose assembly is removed from the compressor, care must
be taken to insure that the hose plate is fully seated to the
compressor during re-installation. Should the plate be
cocked and the retainer bolt driven, metal flanges in the
O-Ring cavities could damage the seal surface of the
compressor.
Some service operations can be performed without
disturbing the internal mechanism, completely removing
the com pressor from vehicle or discharging the system.
Among them are replacement of the clutch drive plate and
hub assembly, clutch rotor and bearing assembly and clutch
coil and pulley rim where "on vehicle" space permits. The
system m ust be discharged, evacuated and charged to
replace the com pressor shaft seal, and pressure relief valve
w hether the com pressor is removed from vehicle or not. The
service operations shown in the following procedure are
based on bench overhaul with compressor removed from
vehicle.
For those operations possible to be performed with
compressor "on the vehicle", the procedure is essentially the
same. The procedures are basically in order of the norm al
sequence of removal for the accessibility of the components.
When necessary to adjust the compressor belt tension,
D O N O T pry on the com pressor shell, lift at square hole
on the com pressor m ounting bracket.
It is recommended that com pressor holding fixture J-
25008-1 (Fig. 68) be used for all "workbench" procedures
to keep the com pressor assembly off the workbench and
help prevent any possible dirt contam ination of parts. The
compressor holding fixture may be clamped in a vise with
shaft end of com pressor in a vertical, horizontal or down
position for service, depending on service to be performed.
COMPRESSOR CLUTCH PLATE AND HUB
ASSEMBLY
Removal
1. A ttach com pressor to holding fixture, J-25008-1
(Fig. 68) and clam p fixture in a vise.
2. Keeping clutch hub from turning with clutch hub
holding tool J-25030, remove and discard shaft nut using
Thin Wall Socket J-9399 (Fig. 69).
3. Thread clutch plate and hub assembly remover J-