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CUSTOM AIR CONDITIONING
1 B-45
Fig. 18-63 Installing 1 9 7 7 A-6 Rear Thrust Races and
Bearings
Front end of piston has an identifvina notch in
-
-
casting web (Fig. 1B-59).
C A U T I 0 N : Exercise care in handling the Piston
and Ring Assembly, particularly during assembly
into and removal fiom the cylinder bores to
prevent damage to the Teflon piston nngs.
Shoe discs should not be installed on rear of
piston during following "Gaging" operation.
Fig. 18-65 Installing 1 9 7 7 A-6 Piston During Gaging
Operation
12. Install rear cylinder half on pistons, aligning cylinder
with discharge cross-over tube hole in front cylinder.
Tap into place using a plastic mallet or piece of clean
wood and hammer (Fig. 1B-66).
13. Position discharge cross-over tube opening between
a pair of Compressing Fixture bolts to permit access for feeler
gage.
14. Install top plate on Compressing Fixture J 9397.
Tighten nuts to 15 lb. ft. torque using a 0-25 lb. ft. torque
wrench.
Gaging Procedure (Steps 15 thru 18)
The gaging operations which follow have been worked
out on a simple basis to establish and provide necessary
running tolerances. Two gaging procedures are necessary.
The first is made to choose the proper size shoe discs
to provide, at each piston, a .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 at the
tightest plate. The bronze shoe discs are provided in .0005"
variations, including a basic ZERO show.
Fig. 18-64 Installing 1 9 7 7 A-6 Front Shoe Disc
8. Rotate shaft and axial plate until high point of axial
plate is over the No. .l Piston cylinder bore.
9. Lift shaft assembly up and hold front thrust race and
bearing assembly against axial plate hub.
10. Position piston over No. 1 cylinder bore (notched end
of piston being on bottom and piston straddling axial plate)
and lower the shaft to allow piston to drop into its bore (Fig.
1 B-65).
11. Repeat Steps 6 through 10 for Pistons No. 2 and No.
3.
The second, performed at the rear shaft thrust bearing
and race pack, is designed to obtain .0025" to .0030" preload
between the hub surfaces of the axial plate and the front and
rear hubs of the cylinder. A total of 14 steel thrust races,
including a basic ZERO race, are provided in increments of
.0005" thickness to provide the required fit.
Feeler and Tension Gage Set J 9564-0 1 or J 9661-01 may
be used for gaging proper shoe disc size. Feeler Gage Set J
9564-01 or Dial Indicator Set J 8001-3 may be used to
determine proper thrust race size.
PROPER SELECTION O F THRUST RACES AND
BALL SEATS IS O F EXTREME IMPORTANCE.
15. Measure clearance between rear ball of No. 1 Piston
and axial plate, in following manner:
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