GMC 1982 Light Duty Truck Service Manual page 132

ID -1 6 AIR CONDITIONING COMPRESSOR OVERHAUL
Fig. 1D-39 Assembling A-6 Cylinder Halves
of 14 steel thrust races, including a basic Z E R O race, are
provided in increm ents o f ,01mm (.0005") thickness to
provide the required fit.
Feeler and Tension G age Set J 9564-01 or J 9661-01
may be used for gaging proper shoe disc size. Feeler Gage
Set J 9564-01 or D ial Indicator Set J 8001 may be used to
determ ine proper thrust race size.
Proper selection of th ru st races and ball seats is of
extrem e im portance.
15. M easure clearance between rear ball of No. 1 Piston
and axial plate, in following manner:
a. Select a suitable com bination of well-oiled Feeler
Gage leaves to fit snugly between ball and axial plate.
b. A ttach Tension G age J 9661-3 to the feeler gage. A
distributor point checking scale or Spring Scale J 544 may
be used.
c. Pull on Spring Scale to slide Feeler G age stock out
from between ball and axial plate, and note reading on
Spring Scale as Feeler G age is removed (Fig. ID-40).
Reading should be between 4 and 8 ounces.
d. If reading in Step "c" above is under 4 O R over 8
ounces, reduce o r increase thickness of Feeler G age leaves
and repeat Steps a. through c. above until a reading of 4 to
8 ounces is obtained. R ecord the clearance between ball and
axial plate th at results in the desired 4 to 8 ounce pull on
Spring Scale.
16. Now rotate shaft 120° and repeat Step 15 between
this same No. 1 Piston R ear Ball and axial plate. Record
this m easurem ent.
If shaft is hard to rotate, install shaft nut onto shaft and
turn shaft with wrench.
204963
Fig. 1D-40 Gaging A-6 Rear Piston Ball
17. R o tate shaft a n o th e r 12(P and again re p ea t Step
15 betw een th ese sam e p a rts and re c o rd m easu rem en ts.
18. Select a "num bered" shoe disc corresponding to
m inim um feeler gage reading recorded in the three checks
just m ade above. (See example in Fig. ID-42). Place the
selected shoe discs in Parts T ray J 9402 com partm ent
corresponding to Piston No. 1 and R ear Ball pocket
position.
Shoe discs are provided in .01mm (.0005") (one-half
thousandths) variations. There are a total of 11 sizes
available for field servicing. All shoe discs are m arked with
the shoe size, which corresponds to the last three digits of
the piece part num ber. (See Shoe Disc Size C hart in Fig.
ID -41.)
Once a proper selection of the shoe has been made, the
m atched com bination of shoe disc to rear ball and spherical
cavity in piston m ust be kept in proper relationship during
disassembly after Gaging operation, and during final
assembly into the Internal C ylinder and Shaft Assembly.
19. Repeat in detail the same G aging Procedure
outlined in Steps 15 through 18 for Piston No. 2 and No.
3.
20A. M ount D ial Indicator J 8001 on edge of
Com pressing F ixture J 9397 w ith C lam p J 8001-1 and Sleeve
J 8001-2 (Fig. ID-43). Position D ial Indicator on rear end
of axial shaft and adjust to " zero."
F rom bottom , apply full hand-force at end of shaft a
few times before reading clearance. This will help squeeze
the oil out from /betw een m ating parts. Now push upward
again and record m easurem ent. D ial Indicator increm ents
are .03mm (.001"); therefore, reading m ust be estim ated to
nearest .01mm (.0005".).