AIR CONDITIONING COMPRESSOR 1-7
Pressure Relief Valve
When a faulty pressure relief valve, located in the rear
head casting, is encountered, the valve assembly should
be removed after purging the system and a new valve and
gasket installed. The entire system should then be
evacuated and recharged.
Compressor Rear Head and Internal Mechanism
Service operations to the rear head or internal mech-
anism of the compressor should be performed with the
compressor removed from the vehicle to insure that the
necessary degree of cleanliness may be maintained.
Clean hands and a clean bench, preferably covered with
clean paper, are of extreme importance.
Rear Head, Oil Pump and Valve Assemblies
Removal
1.
Remove the compressor from the vehicle, drain
compressor oil into a clean container, clean the
exterior of the compressor case and rear head cast-
ing with a suitable solvent and mount the compres-
sor, rear head up, in holding Fixture J-9396 which
should then be mounted securely in a vise.
2.
Remove the four nuts from the shell studs.
3.
Remove the rear head. Examine the teflon surface
on the casting webs. If this surface is damaged by
nicks or scratches, the head should be replaced.
4.
Examine the suction screen in the rear head for any
damage or contamination. Clean or replace the
screen as necessary.
5.
Remove and examine the oil pump gears. If either of
the gears shows any wear or damage, replace both
gears.
NOTE: Keep the ends of the two oil pump gears
matched and replace the same end toward the
discharge plate upon reassembly.
6. Remove the rear head-to-shell "O" ring and dis-
card.
7.
With two screw drivers, carefully pry up on the rear
discharge valve plate assembly (fig. 14). Check for
broken reeds or damaged seats and replace entire
assembly if such is found.
CAUTION: Excessive force during this opera-
tion may loosen valve reed retainer rivets.
8. Carefully lift off the rear suction reed valve. Valve
must be replaced if any damage is evident.
Installation
1.
Carefully replace the suction reed valve and the
rear discharge plate over the dowel pins and ports in
the cylinder assembly. Proper positioning of the reed
plate may be determined by lining up the proper
opening in the plate with the discharge crossover
tube opening.
Position the rear head casting to align with the dowel
pins.
The two lower mounting pads will be in align-
ment with the oil sump in the shell. Rotate the
cylinder assembly back and forth by hand, if neces-
sary, to permit this alignment. Remove the rear
head from this trial assembly.
Install the inner oil pump gear over the "D" flat on
the shaft and place the outer oil pump gear over the
inner gear. Position the outer gear as follows:
a. Observe the position of the oil sump in the shell.
2.
3.
Fig.
14—Removing Rear Discharge Valve Plate
5.
6.
b.
Locate the approximate centerline of this pump.
c. Facing the centerline of the sump and viewing
from the sump side (bottom) of the compressor,
move the OUTER gear toward the right (side
having the^ oil drain fitting) until it is at approxi-
mately 90° (3 o'clock position) from the centerline
of the oil sump (fig. 15).
Coat the head-to-shell "O" ring with clean refrig-
eration oil and generously lubricate the area around
the outer edge of the valve plate where the "O" ring
will be placed. Oil also the oil pump gears, valve
reeds and the area where the teflon gasket will
contact the valve plate.
Install the head-to-shell "O" ring.
Be sure that the suction screen is properly posi-
tioned in the rear head, then assemble the rear head
to the compressor shell being careful not to damage
the teflon gasket.
Fig.
15—Proper Oil" Pump Gear Positioning
CHEVROLET CHASSIS OVERHAUL MANUAL