assembly (30) and their associated gaskets (27 and 31),
gasket back-up rings (28 and 32) and fitting nuts (29 and
(70) from second stage cylinder (85). If necessary,
33) in inlet and outlet ports of second stage cylinder (85)
remove holddown screw (63), retainer ring (64) and
in accordance with instructions in paragraph 4.5.7.
rupture disc (65) from cylinder cap (66).
d. Remove attaching nuts (86) and carefully slip
g. Reconnect interstage connecting tubes (21 and
second stage cylinder (85) free Of piston and crankcase.
22) to second stage fittings.
Remove and discard cylinder-to-crankcase gaskets (87
4.14.5
REPLACING THIRD STAGE CYLINDER,
and 88).
PISTON AND VALVE MECHANISM
e. Remove cotter pin (90) and carefully push wrist
4.14.5.1
Removal, inspection and reassembly of the
pin (89) free of second stage piston and connecting link
third stage cylinder, piston and valve mechanism is
(95). Be careful not to lose 25 needle bearings (93) and
essentially the same as for the second stage.
two link washers (92) which drop free as piston is
withdrawn from connecting link Scribe small mark inside
NOTE
piston skirt to identify side of piston toward fan end of
Nominal poppet lift of third stage is
crankcase.
0.034 inch.
f. Do not remove poppet pin and poppet from piston
4.14.6
SECOND AND THIRD STAGE SMRAINE
unless replacement parts are required. Nominal poppet
AND RELIEF VALVE NOTE: Third stage valve
lift should be 0. 222 inch.
applicable on Mode1 3800219 only.
4.14.4.2
INSPECTION. Inspect all parts in accordance
4.14.6.1
REMOVAL.
Refer to paragraph
with instructions in paragraph 4.14.3.2.
steps a and b.
4.14.4.3
REASSEMBLY
4.14.6.2
DISASSEMBLY (See Figure 5-13).
a. Place 25 needle bearings (93) around edge of
a. Unscrew spring adjusting plug (1) and remove
wrist pin hole at end of second stage connecting link (95).
spring(2), poppet (3), seat (4), and seat retainer screw (5)
Place link washer (92) at each end of needle bearings.
from seat housing (6).
Carefully position second stage piston over connecting
link and press wrist pin (89) through piston, link washers
b. Remove seat retainer screw (5) and seat (4) from
and bearings. Secure wrist pin with 5/8inch long cotter pin
poppet (3).
(90).
c. Unscrew seat housing (6) from elbow body (10)
NOTE
and remove packing (7), spring (8) and strainer (9).
Assembly of needle bearings and
4.14.6.3
CLEANING AND INSPECTION. Clean all
link washers in connecting links is
parts by washing in dry-cleaning solvent (Federal
simplified by coating parts with
Specification P-S-661). Thoroughly dry parts with clean,
Petrolatum Federal SpecificationW-
lint-free cloths and/or filtered compressed air. Inspect
parts for nicks, scratches, scoring and other damage or
P-236).
wear. Examine springs for signs of set or out-of-round.
b. Places the gasket (88), flanked by paper gaskets
Springs must be cylindrical in shape with ends squared,
(87), on mounting flange of second stage cylinder (85).
closed and ground. Discard all worn, damaged or
Carefully slip cylinder over piston and press firmly into
questionable parts.
crankcase mounting hole. Install nuts (86) on studs and
4.14.6.4
REASSEMBLY (See Figure 5-13).
tighten with equal torque.
a. Slip packing (7) into groove of seat housing (6).
c. Use same procedure specified in paragraph
Place strainer (9) and spring (8) in elbow body (10).
Screw seat housing into elbow body and tighten with a
valve-seat clearance. Required clearance is 0.002 to
torque of 250 pound-inches.
0.006 inch.
b. Place seat (4) in counterbore of poppet (3) and
d. Install rupture disc (65) and retainer ring (64) in
secure in position with screw (5).
cylinder cap (66). Screw holddown screw (63) into cap
and tighten with a torque of 350 pound-inches.
c. Place poppet assembly and spring (2) in seat
housing (6). Install spring adjusting plug (1).
e. Place packing (67) in groove of second stage
4.14.6.5
ADJUSTMENT AND TEST
cylinder cap (66). Install exhaust valve (70), spring (69)
and spring washer (68) in second stage cylinder (85).
a. Connect a variable source of compressed air to
Screw cylinder cap and rupture disc into cylinder and
one threaded port of elbow body. Connect a pressure
tighten with a torque of 300 to 350 pound inches.
gage to other port.
f. Install elbow (25) and strainer and relief valve
39
