TM 3-1040-263--34
(3) Remove fan group (para 4--5).
(6) Check piston pin outside diameter
(4) Remove nut (1, fig 3-3) and screw (2)
holding second-stage heat exchanger and aftercooler
(7) Check piston pin (6) bore (para 1-4c)
d. Reassembly.
clamp (3) at point A.
(5) Remove first-stage strainer and filter
(1) Position piston pin (4, fig. 4-7) into the
assembly (TM 3-1040-263--12).
piston-pin orifice with the retaining ring recess in the
b. Disassembly.
piston (6). Assemble retaining ring (3) to the inside
(1) Disconnect first-, second-, and third-
groove in piston pin.
stage heat exchanger end nuts (fig. 3-3).
(2) Route the piston pin (4) to the piston
(2) Remove six studs (4, fig. 4-6) with nuts
orifice with retaining ring recess, and assemble retaining
(2), washers (3) intercooler brackets (5 through 7), and
ring (1). Then, using dial indicator, determine piston pin
head (12) with assembled parts from cylinder (23).
end play. Remove or add shims (2) as required to obtain
Remove elbow (1).
an end play of 0.001 inch maximum. Shimming must
allow for free rotation of piston pin (4) while restricting the
end play as specified.
NOTE
(3) Disassemble the retaining ring (1),
selected shims (2), retaining ring (3), and piston pin (4)
Removal of valve disk stop (8) and stop
from the piston (6).
shims
(9
through
11)
is
not
recommended unless damaged or
CAUTION
discharge valve travel adjustment is
required.
Do not allow the keystone assembly to
(3) Remove the valve disk stop (8) and
contact the inside of the crankcase when
stop shims (9 through 11) from the first-stage head (12).
rotating the crankshaft.
(4) Remove the outlet spring (13), outlet
valve (14), and head gasket (15) from the plate and pin
(4) While keeping the keystone assembly
(16).
from contacting the inside of the crankcase, rotate the
(5) Remove the plate, and pin (16), inlet
crankshaft until the keystone assembly is as far out of
valve (17), and plate gasket (18) from cylinder (23).
the crankcase as possible through the first-stage piston
(6) Remove the cylinder (23) with
hole.
assembled parts from the compressor.
(5) Position piston (6) over keystone
(7) Remove the preformed packing (19)
assembly with snap ring grooves in piston (6) over
and shims (20 through 22), if present, from the cylinder
second-stage section of crankcase. Insert piston pi (4)
(23).
into piston-pin orifice, opposite orifice with retaining ring
(8) Disassemble retaining ring (1), and
recess in piston, and into piston hole in the keystone
remove piston pin shims (2) and retaining ring (3) with
assembly. Position retaining; ring (3) snug into inside
piston pin (4) from the piston (6).
groove in piston pin.
(9) Remove compression rings (5).
(6) Route the piston pin (4) to the piston
c. Cleaning and inspection.
pin orifice with retaining ring recess, and assemble shims
(1) Remove carbon deposits in head (12,
((2) above) and retaining ring (1) into, piston pin outside
fig. 4-6), outlet valve (14), inlet valve (17), plate and pin
groove.
(16), and outlet spring (13), using stiff bristle brush and
(7) Position cylinder (23, fig. 4-6) with
drycleaning solvent.
0.040-inch thickness shims (20, 21, and 22) onto piston
(2) Clean remaining metal parts in
(6, fig. 4-6); and secure cylinder and shims in place,
drycleaning solvent.
using two studs (4, fig. 4-6) and nuts (2) positioned on
(3) Inspect threads for damage.
opposite sides of cylinder. (23).
(4) Inspect parts for wear and damage.
(8) With cylinder (23) secured, refer to
(5) Inspect outside surfaces of piston pin
figure 4-8 and, using depth micrometer, determine
(4, fig. 4-7) to determine that pin is round and free of
measurements required to calculate the thickness of
nicks, scratches; or burrs.
shims (20, 21, and 22, fig. 4-6) needed to provide proper
head clearance. With proper thickness shims, the first-
stage head clear-
4-11
