TM 9-4940-549-14&P
Protect lip of the seal from cutting
by the threads on end of crankshaft by
wrapping a sheet of 0.003 inch brass
shim stock around threads, then slip-
ping shaft end cover and seal into po-
sition on frame.
(3) Place gasket (15) in position around shaft, then install shaft
end cover and seal as described in caution above. Secure cover
with four steel washers (12) and capscrews (11). Install connec-
tor tube (10) and breather tube (9) in frame (17), then install
nipple (7), coupling (6), and plug (5).
NOTE
Refer to figure 14-9 for steps (4)
through (9).
(4) Install connector (25, figure 14-9) and connecting rod (24).
Check clearance between crankpin bushing and connecting rod.
It should be between 0.001 and 0.002 inch. If clearance is
0.0025 inch replace bushing and connecting rod.
(5)
Measure the clearance between piston pin (19) and piston (20).
This is a very close tolerance. It should be between 0.0003
inch and 0.0009 inch. If clearance is as much as 0.0012 inch
replace pin and piston. Install pin (19) through rod (24) and
piston (20), and secure with the lockrings (18).
Place piston rings in cylinder bore
to measure end gap before installa-
tion in ring grooves. Also measure
piston to bore clearance. If ring
end gap is between 0.005 and 0.015
inch, they are satisfactory. If
piston clearance in bore of high
pressure cylinder (1-3/4 inch dia.)
is between 0.0025 and 0.0035 inch
the clearance is satisfactory. Pis-
ton pin to connecting rod clearance
should be between 0.0002 and 0.0007
inch. if in range, they are satis-
factory.
(6) Before installing rings, see that all ring grooves are lubricated
with compressor lubricating oil.
(7) Install ring (23 ) in bottom groove of piston (20). Install the
expander in groove first, before ring (22), in the second groove
from bottom of piston, then install ring (21) in the second
groove from top, and the top groove of piston (20). Turn end
gaps of ring until they are staggered at 90 to each other.
14-18
