GMC 1976 ZEO 6083 Maintenance Manual page 107

1- 90 AIR CONDITIONING SYSTEM
Figure 83-Checking Piston and Shaft End Play
Apply full hand-force at end of mainshaft a few
times before reading clearance. This will help
squeeze the oil out from/ between mating parts.
Push upward and record measurement. Dial Indica-
tor increments are 001" ; therefore, reading must be
estimated to nearest .0005" .
An alternate method of selecting a proper race is
to use Gage Set J-9661-01, selecting a suitable feeler
gage leaf until the result is a 4 to 8 ounce pull on the
scale between the rear thrust bearing and upper (or
outer rear) thrust race (figure 83). If the pull is just
less than 4 ounces, add .0005" to the thickness of the
feeler stock used to measure the clearance. If the pull
on the scale reads just over 8 ounces, then subtract
.0005" from the thickness of the feeler stock.
Select
a race TWO (2) FULL SIZES LARGER than feeler gage thick-
ness (If feeler gage is .007", select a No. 9 or 090
race).
21 .
Select a thrust race with a "number" corresponding
to TWO (2) FULL SIZES LARGER than Dial Indicator or feeler
gage measurement of the amount of end play shown .
(If
measurement is .007", select a No . 9 or 090 race) .
Place thrust race in right-hand slot at bottom center of Parts
Tray J-9402 .
Fifteen (15) thrust races are provided in incre-
ments of .0005" (one-half thounsandths) thickness
and one ZERO gage thickness, providing a total of
16 sizes available for field service. Thrust races are
identified on the part by their thickness in thou-
sandths, in excess of the thickness of the ZERO
thrust race .
This "number" also corresponds to the last three
digits of the piece part number . See Thrust Race size
Chart in Figure 80 .
22 . Remove nuts from top plate of Compressing
Fixture J-9397, and remove top plate.
23 . Separate cylinder halves while unit is in Fix-
ture . It may be necessary to use a wood block and
mallet .
24.
Remove rear cylinder half and carefully remove one
piston at a time from axial plate and front cylinder half . DO
NOT LOSE THE RELATIONSHIP of the front ball and shoe
disc and rear ball . Transfer each piston, ball, and shoe disc
to its proper place in Parts Tray J-9402 .
25 . Remove rear outer ZERO thrust race from
shaft and install thrust race just selected .
The ZERO thrust race may be put aside for re-
use in additional gaging or rebuilding operations .
TEFLON PISTON RING REPLACEMENT
The Teflon piston ring installing, sizing and gag-
ing tools are shown in Figure 84 .
J-24608-2 RING
INSTALLER GUIDE
J-24608-5
RING INSTALLER
J-24608-6 RING
SIZING TOOL
J-24608-1 PISTON
RING GAUGE
Figure 84-Teflon Piston Ring Installing, Sizing , and Gaging Tools