Gaging Procedure - GMC 1989 Light Duty Truck Repair Manual

1B1-14 A-6 AIR CONDITIONING COMPRESSOR
Figure 30— In sta lling the P iston d u rin g the
G aging O peration
Im portant
• Do not install th e shoe discs (35) on the
rear of th e piston (32).
9. Rotate the shaft and axial plate (39) until the high
point of the axial plate is over the No. 1 piston
cylinder bore.
10 Lift the axial shaft assem bly (39) up a little out of
.
front cylinder half (29).
• Hold the front thrust races and bearing (" zero "
race, race bearing, " ze ro " race) against the
axial plate hub.
11. Position the No. 1 piston (32) over the No. 1 cylinder
bore (notched end of the piston being on the bottom
and the piston straddling the axial plate) and lower
the shaft to allow No. 1 piston to drop into its bore
(figure 30).
12
R e p e at step 11 for pistons Nos. 2 and 3.
.
13. Install the rear cylinder half (42) on the pistons,
aligning the cylinder with the discharge cross-over
tube hole in the front cylinder.
• Tap the piston into place using a plastic m allet
or piece of clean wood and a h am m er (figure
31).
14. Position the d is ch arg e cross-over tu b e o penin g
betw een a pair of com pressing fixture bolts to perm it
access for the feeler gag e.
15.
Install the top plate to J 9397.
Tighten
Nuts to 20 N m (15 ft. lbs.).

GAGING PROCEDURE

Tools R equired:
J 8001 Dial Indicator Set
J 9 3 9 7 Com pressing Fixture
J 9 4 0 2 Piston A ssem bly Tray
J 9661-01 Feeler Tension G a g e Set
Two gaging procedures provide the running tolerances.
T h e first procedure determ ines the size shoe discs to
p r o v id e a t e a c h p is to n
(0 .0 0 1 6 -0 .0 0 2 4 -in c h ) total preload b etw een the seats and
the axial plate at the tightest p lace through the 36 0
d eg ree rotation of the axial plate. T h e b ro nze shoe discs
are available in 0.013 mm (0.0005-in ch ) variations.
T h e second procedure, perform ed at the rear shaft
thrust bearing and race pack, provides a 0 .0 6 4 -0 .0 7 7 mm
(0 .0 0 2 5 -0 .0 0 3 0 -in c h ) preload betw een the hub surfaces of
the axial plate, and the front and rear hubs of the cylinder.
Fourteen steel thrust races, including a basic " ze ro " race,
are available in 0.013 mm (0.0005-in ch ) increm ents. Use
J 9661-01 for gaging the shoe disc size. U se J 8001 to
d eterm ine the thrust race size.
1. M ea su re the clearan ce b etw een the rear ball of the
No. 1 piston and axial plate in the following manner:
a. S ele ct a co m b inatio n of oiled fe e le r gage
leaves to fit snugly b etw een the ball and axial
plate.
b. A tta c h J 9 6 6 1 -0 1
distributor point checking scale m ay be used.
c. Pull on the spring scale to slide the feeler
g ag e stock out from betw een the ball and axial
plate. Note the reading on spring scale as the
a 0 . 0 4 1 - 0 .0 6 1 m m
to th e f e e le r g a g e . A