R-4 C O M P R E S S O R Sh Ell A N D /O R O -R In G S - GMC 1982 Light Duty Truck Service Manual

4. "Evacuate and Charge the Refrigerant System" according to
the directions in Section 1B1.

R-4 C O M P R E S S O R SH ELL A N D /O R O -R IN G S

Remove
1. "Discharge the Refrigerant System" according to the
directions in Section 1B1.
2. Thoroughly clean exterior of compressor to prevent dirt from
getting into compressor during shell removal.
3. Remove the Clutch Plate and Hub assembly as described in
"Compressor Clutch Plate and Hub" Removal procedures.
4. Perform Steps 1 through 4 of "R-4 Compressor Clutch Rotor
and/or Bearing" Removal procedure but do not loosen or
remove the pulley rim mounting screws so as to remove the
Clutch Rotor and Bearing, Clutch Coil and Pulley Rim as
a total assembly. Be careful not to drop the Puller Guide J
25031 when removing the assembly.
5. Pry the shell retaining strap away from the cylinder and
position the strap high enough to clear the cylinder as the
Shell is removed (Fig. 1C1-40).
Fig. 1C 1 -40 Releasing Shell Retaining Strap
6. Remove Compressor Holding Fixture J 25008-1, and reverse
Holding Fixture with step block protrusions engaging the
compressor Shell. Install the medium-length metric thread
mounting bolts through the Holding Fixture and thread them
finger-tight on both sides into the compressor cylinder until
the step of the fixture protrusions contact the compressor
Shell (Fig. 1C1-40). Check to be sure the step protrusions do
not overlap the cylinder but will pass both sides. Allow
P H R E T A I N E R S T R A P
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F I X T U R E
AIR C O N D ITIO N IN G COMPRESSOR O VERHAUL 1C 1-15
compressor to cool to room temperature before removing
compressor shell.
Fig. 1C 1-41 Removing Shell
7. Alternately tighten each bolt approximately 1/4 turn to push
the Shell free of the O-rings on the cylinder (Fig. 1C 1-41).
If one (1) screw appears to require more force to turn than
the other, immediately turn the other screw to bring the screw
threading sequence in-step or the Shell will be cocked and
made more difficult to remove. Normal removal does not
require much force on the wrench if the screws are kept in­
step while turning. The Shell can be removed by hand as soon
as the Shell is free of the shell to cylinder O-rings. Do not
turn the screws any further than necessary to release the
Shell.
8. Remove the compressor Shell and remove the Holding
Fixture J 25008-1 from the compressor. Reverse the Holding
Fixture to again hold the compressor by the opposite side,
using the short-length screws with metric threads.
9. Remove and discard both cylinder to Shell O-rings.
Replace
1. Check the compressor cylinder assembly and interior of the
compressor Shell to be sure they are free of lint, dirt, etc.
2. Dip a new cylinder-to-shell O-ring in clean 525 viscosity
refrigerant oil and install in the rear O-ring groove of the
cylinder. Be careful in moving the O-ring across the cylinder
surface to prevent damaging the O-ring.
3. Dip the remaining cylinder-to-shell O-ring in the 525 oil and
install it in the front O-ring groove of the cylinder.
4. Also coat inner O-ring surface of compressor Shell with oil.
Place the compressor Shell on the cylinder and rotate the
retaining strap to its original location.
5. Attach the Shell Installing Fixture J 25008-2 to the Holding
Fixture J 25008-1, using the long-bolts and plate washers of
the set. Align the step projections of the Installing Fixture
J 25008-2, to contact the compressor Shell evenly on both
sides.
6. Push the compressor shell as close to the O-ring, Fig. 1C1-42,
as possible by hand and check for equal alignment of the shell
around the cylinder. Tighten the Fixture screws finger tight.
7. Alternately tighten each bolt approximately 1/4 turn to push
the compressor Shell over the O-rings and back against the
shell stop flange at the rear of the compressor cylinder.
If one (1) screw appears to require more force to turn than
the other, immediately turn the other screw to bring the screw
threading sequence in-step or the shell will be cocked and
made more difficult to install. Normal installation does not
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H O L D I N G
F I X T U R E
H H S H E L L T O
C Y L I N D E R
O - R I N G
[ T l A L T E R N A T E L Y
T I G H T E N
S C REW S
A P P R O X .
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