Pontiac FIREBIRD 1972 Service Manual page 140

CUSTOM AIR CONDITIONING 1A-81
Fig. 1A-92 Checking Compressor Mainshaft End Play
a. Mount dial indicator to read clearance at end of
compressor shaft.
b. Move compressor shaft along its longitudinal axis
and measure end play. (NOTE: Apply full hand
force at end of mainshaft a few times before read-
ing clearance. This will help squeeze the oil out
from between mating parts.)
c. An alternate method of selecting a proper race is
to use J 9661 gauge set, selecting a suitable feeler
gauge leaf until the result is a 4 to 8 oz. pull on
the scale between the rear thrust bearing and up-
per (or outer rear) thrust race (Fig. 1A-93). If the
pull is just less than 4 ozs., add .0005" to the
thickness of the feeler stock used to measure the
clearance. If the pull on the scale reads just over
8 ozs., then subtract .0005" from the thickness of
the feeler stock. Select a race accordingly.
d. Select from stock a numbered thrust race that
corresponds to dial indicator reading. (Thrust
races are made of steel and ground to a fixed
thickness. A total of fourteen thrust races are
available for field service in increments of .0005"
thickness to provide the required clearance.)
The thrust races will be identified on the part by
their thickness, and the number on thrust race
will correspond to the last three digits of the piece
part number.
If an improper selection of thrust races or shoes
is made and the tolerance is GREATER than the
maximum clearance, noisy operation of the com-
pressor will result. If the tolerance is LESS than
the minimum clearance, it is likely that the mech-
anism assembly will be too tight. This may result
in galling and seizure of parts.
Fig. 1A-93 Measuring for Proper Thrust Race
Therefore, it is very important that care be used
during gauging operations and the proper selec-
tion of parts be made. Once selection has been
made, be sure parts are assembled into the correct
position in the mechanism.
e. Mark the package "REAR thrust race" or place
it in J 9402 assembly parts tray corresponding to
this position.
16. Loosen and remove nuts and ring from J 9397 com-
pressing fixture.
17. Separate cylinder halves (it may be necessary to use
a fiber block and mallet).
18. Remove rear half cylinder
19. Carefully remove one piston at a time from swash
plate and front half cylinder. Do not lose relationship
or position of front ball and shoe and rear ball. Trans-
fer each piston, balls and shoe assembly to its proper
place in the J 9402 assembly tray.
20. Remove REAR outer ZERO thrust race from shaft
and replace it with numbered thrust race determined
in step 15. Apply a LIGHT smear of petrolatum to
'
thrust races to aid in holding them in place during
assembly. NOTE: This ZERO thrust race may be put
aside for reuse in additional gauging and/or rebuild
operations.
21. Apply a light smear of petrolatum to numbered shoes
and place them over correct ball in rear of piston.