parts are supplied in the form of Repair Kits (refer to parts
b. Install steel gasket (99), flanked by two paper
list for Figure 5-12). Further disassembly of the air
gaskets (98), against mounting flange of first stage
compressor is obvious by studying the exploded view,
cylinder (96).
Figure 5-12.
c. Slip first stage cylinder (96) over installed piston
NOTE
and press into crankcase mounting hole. Cylinder must
be installed with leading edge of cooling fins slanted
When repairing the applicable
toward fan end of compressor. Secure cylinder to
sections of the compressor, replace
crankcase with nuts (97), being sure to tighten nuts with
all parts removed in the process of
an equal torque.
disassembly,
regardless
of
condition, with all like parts
d. Use a depth micrometer or dial indicator to
furnished in the kit.
measure piston-head-to-valve-plate clearance. Required
clearance is 0.021 to 0.026 inch. If necessary, remove
4.14.3
REPLACING
FIRST
STAGE
CYLINDER,
cylinder and add or remove cylinder-to-crankcase
PISTON AND VALVES
gaskets to obtain required clearance.
4.14.3.1
REMOVAL
NOTE
Overall thickness of steel gaskets
a. Remove attaching screws (8) and lock washers (9)
can be reduced in increments of
and lift silencer cover (7) and intake filter (10) from first
0.002
inch
by
peeling
off
stage cylinder head (71).
laminations. At least one paper
b. Loosen coupling nut and disconnect first-to-second-
gasket must remain on each side
stage connecting tube (22) from the fitting (26) installed in
of steel gasket in final installation.
first stage outlet port.
e. Install packing (83) in groove in first stage
c. Loosen nut (29) and unscrew the fitting from first
cylinder head (71). Assemble valve stop (82), exhaust
stage outlet port. Remove gasket (27), gasket back-up ring
spring (81), exhaust valve (80), valve plate (79), intake
(28) and nut from the fitting.
valve (78), and intake valve spring (74).
Attach
assembled parts to cylinder head with screw (75), flat
d. Remove flat head screws (72) and lift first stage
washer (77), and nut (76).
cylinder head (11), gasket (73), and complete valve
f. Position first stage cylinder head and valve
mechani3m (items 74 through 83) free of first stage
assembly and gasket (73) on first stage cylinder so that
cylinder.
cooling fins all slant in same direction. Install flat head
e. Remove valve retainer screw (75), nut (76), and
screws (72) and tighten with a torque of 25 pound inches.
flat washer (77), and separate intake valve spring (74),
g. Install the fitting (26), gasket (27), gasket backup
intake valve (78), valve plate (79), exhaust valve (80),
ring (28) and nut (29) in outlet port of first stage cylinder
exhaust spring (81), valve stop (82), and packing (83) from
head (refer to paragraph 4.5.7).
first stage cylinder head (71).
h. Attach intake filter (10) and silencer cover (7) to
f. Unscrew four nuts (97) and slip first stage cylinder
first stage cylinder head (71) with two screws (8) and lock
(96) free of piston and crankcase (117). Remove and
washers (9).
discard cylinder -to-crankcase gaskets (98 and 99).
i. Reconnect first-to-second-stage connecting tube
g. Remove two retaining rings (101) and push wrist
(33) to the fitting (26).
pin (100) free of piston and master rod (113). Identify side
4.14.4
REPLACING SECOND STAGE CYLINDER,
of piston toward fan end of crankcase by scribing a small
PISTON AND VALVE MECHANISM
mark inside piston skirt.
4.14.3.2 INSPECTION. Carefully inspect all parts for
4.14.4.1
REMOVAL
obvious indications of damage such as damaged screw
a. Disconnect connecting tubes (21 and 22) from
threads, finished surfaces that are scratched, pitted or
fittings installed in inlet and outlet ports of second stage
worn, and broken cooling fins on the cylinder. Inspect the
cylinder (85).
cylinder bore, piston, wrist pin, master rod and needle
bearings for excessive wear, scoring and other damage.
b. Loosen nuts (29 and 33) and unscrew elbow (25)
and strainer and relief valve assembly (30) from ports of
Refer to Table 5 for the original dimensions and
second stage cylinder. Remove gaskets (27 and 31),
permissible wear of these parts.
gasket back-up rings (28 and 32) and nuts from fittings.
4.14.3.3
REASSEMBLY
(Refer to paragraph 4.14.6.2 for disassembly of strainer
and relief valve assembly.)
a. Attach first stage piston (96) to master rod(113,
c. Unscrew cylinder cap and rupture disc assembly
and needle bearings (112) with wrist pin (100) and retaining
(63 through 66) and remove packing (67), spring
rings (101).
37
