GMC 1982 Light Duty Truck Service Manual page 131

5. Now install a zero th ru st race on rear end of
com pressor axial shaft (Fig. ID-36), so th at it rests on hub
o f axial plate. T hen add one thru st bearing and a second zero
th ru st race onto shaft.
A t this point, both front end and rear end o f axial shaft
will have a stack-up of one zero race-one bearing-one zero
race.
THRUST BEARING
THRUST RACE
COMPRESSING
FIXTURE
J-!
HOLDING FIXTURE
J-9396
Fig. 1D-36 Installing A-6 Rear Thrust Races and Bearings
6. Lubricate ball pockets of the No. 1 Piston with 525
viscosity refrigerant oil and place a ball in each socket. Use
balls previously removed if they were considered acceptable
for re-use.
7. Lubricate cavity o f a zero shoe disc w ith 525 viscosity
refrigerant oil and place shoe disc over ball in front end of
piston (Fig. ID-37). F ro n t end o f piston has an identifying
notch in casting web (Fig. ID-32).
NOTICE:
Exercise care in handling the Piston and
Ring Assembly, particularly during assembly into and
rem oval from the cylinder bores to prevent dam age to
the Teflon piston rings.
Shoe discs should not be installed on rear of piston
during following "G aging" operation.
BALL
Fig. 1D-37 Installing A-6 Front Shoe Disc
AIR CONDITIONING COMPRESSOR OVERHAUL 1D-15
THRUST RACE
FRONT
CYLINDER
H A I F
TEFLON RING
204979
8. R otate shaft and axial plate until high point of axial
plate is over the No. 1 Piston cylinder bore.
9. Lift the axial shaft assembly up a little out o f front
cylinder half and hold front thru st race and bearing
assembly ("zero" race-bearing-" zero" race) against axial
plate hub.
10. Position No. 1 Piston over No. 1 cylinder bore
(notched end of piston being on bottom and piston
straddling axial plate) and lower the shaft to allow No. 1
Piston to drop into its bore (Fig. ID-38). If ball and shoe
will not rem ain in front socket of piston during assembly
use a light sm ear of petrolatum on the piston and shoe ball
socket surfaces.
REAR NEEDLE
THRUST BEARING
AND "ZERO "THRUST
RACES
FRONT CYLINDER
Fig. 1D-38 Installing A-6 Piston During Gaging Operation
11. Repeat Steps 6 through 10 for Pistons No. 2 and
No. 3.
12. Now install rear cylinder half onto pistons, aligning
cylinder w ith discharge cross-over tube hole in front
cylinder half.
Tap into place using a plastic mallet or piece o f clean
wood and ham m er (Fig. ID-39).
13. Position discharge cross-over tube opening between
a pair o f Com pressing F ixture J 9397 bolts to perm it access
for feeler gage.
14. Install top plate on Compressing Fixture J 9397.
Tighten nuts to 20 N - m (15 lb. ft.) torque using a 0-60 N • m
(0-25 lb.ft.) torque wrench.
G aging Procedure (Steps 15 th ru 18)
The gaging operations w hich follow have been worked
out on a simple basis to establish and provide necessary
running tolerances. Two gaging procedures are necessary.
The first is m ade to choose the proper size shoe discs
to provide, at each piston, a .04 to .06mm (.0016" to .0024")
total preload between the seats and the axial plate at the
tightest place through the 360-degree rotation of the axial
plate. The bronze shoe discs are provided in .01mm (.0005")
variations, including a basic Z E R O shoe.
The second, perform ed at the rear shaft thrust race and
bearing stack-up, is designed to obtain .06 to .08mm (.0025"
to .0030") preload between the hub surfaces of the axial
plate and the front and rear hubs of the cylinder. A total
PISTON DRIVE
BALL ONLY
AT REAR
PISTON DRIVE
BALL AND
"ZERO" SHOE
DISC AT FRONT
2 0 4 9 5 1