TM 5-4930-218-14
(3) Unscrew and remove the outlet body (16) from
stem (75).
the cylinder support (84).
(18) When cap screws (77) and mounting plate
(4) Remove drain tube (17). Unscrew and remove
(78) are removed, the low pressure cylinder support
drain valve assembly (18 through 23). Disassemble on
assembly (79 through 84) will come out of the cylin-
bench by removing screw (18), stem valve (20),
der. Disassemble the support assembly by removing
packing (21), and bail (22) from valve body (23). Do
the packing nut (79) and packings (80 through 83),
not remove roll pin (19) from stem valve (20).
from the cylinder support (84).
(5) Unscrew the foot valve body (24) from the
b. Cleaning and Inspection.
pump tube (28) and remove retainer (26), ball (27),
(1) Discard and replace all packings.
and packing (25).
(2) Clean all parts with dry cleaning solvent (fed,
spec. P-D-680).
NOTE
To prevent marring surface finishes, use a strap
(3) Inspect and replace any worn or damaged
wrench to hold parts without wrenching flats or parts
parts.
that have polished surfaces, Use a soft-jawed vise when
(4) Inspect threaded surfaces for damage.
clamping parts to disassemble.
(5) Inspect pump rods and tube for breaks,
(6) Unscrew the pump tube (28) from the cylinder
cracks, or other defects which would prevent proper
support (84) and remove the packing (29).
operation.
(7) After nut (30) and piston valve (31) are
c. Repair.
removed, piston assembly (32, 33, and 34), spring (35),
(1) Repairs consist mainly of replacing all
and spring stop (36) will slide off lower pump rod (37).
packings and parts which fail to pass inspection.
Separate piston nut (32), leather cup (33), and piston
(2) You can remove minor nicks or scratches
(34).
using a fine stone, then polish with fine emery cloth
(8) Pull down on lower pump rod (37) to expose
or crocus cloth. Reclean parts after polishing.
wrench flats on upper pump rod (43). Unscrew and
(3) Clean up any damaged threads using a fine
remove lower pump rod.
file or taps and dies of the correct size.
(9) Unscrew cylinder cap (41) from air cylinder
d. Reassembly.
housing (86). Pull out to expose valve spring (38) and
(1) Reassembly is essentially the reverse of
valve spring stop (39). Place large screwdriver in coils
disassembly. Note the following:
of spring (38) and pry downward so spring snaps off
(a) You should apply a light coating of engine
valve spring stop. Valve shifter rod (61) will then
oil on all packings, and on rods and tubes with in-
slide out of keyhole slot in valve spring stop. Remove
terior or exterior sliding surfaces.
spring (38) and gasket (42). Disassemble cylinder cap
(b) When installing low pressure cylinder sup-
by removing eye bolt (40) and spring stop (39).
port assembly (79 through 84) in cylinder (86), you
(10) Pushing against upper pump rod (43), push
must make certain support is positioned so that drain
complete air piston assembly (45 through 76) out of
valve assembly and outlet can be installed in their
air cylinder housing (86).
respective tapped holes.
(11) Unscrew and remove upper pump rod (43).
(c) Assemble valve bar assembly (51 through
Remove packings (44 and 85).
64) and install on air piston (76) before installing
(12) Remove cap screws (45), bearings (46), and
items 45 through 50. When installed, check action of
trip springs (47).
valve bar. Bar should move up and down freely with
(13) To remove valve bar assembly (items 51
no binding on the valve shifter (62).
through 64), first remove nuts (48), washers (49), and
(d) Before installing cylinder cap (41), be sure
air valves (50). Lift valve bar assembly off piston (76).
spring (38) is snapped in place on valve spring stop
(14) Disassemble the valve bar assembly by
(39) and that valve shifter rod (61) is engaged in
removing nuts (51 and 55), washers (52), intake valve
keyhole slot of spring stop.
stem (53), exhaust valve stem (56), air valve (57), and
(e) Assemble drain valve assembly (18 through
washers (54 and 58) from valve bar (64). Remove
23) on the bench, then install through hole provided
spring stop (59), spring (60), shifter rod (61), shifter
in air cylinder. Make certain tapped hole in body is
(62), and shifter sleeve (63) from valve bar (64).
alined with hole in mounting flange, then install
(15) Remove intake valve seat (65) and exhaust
drain tube (17).
valve seat (66) from air piston.
(f) Assemble oiler assembly (1 through 15) on
(16) Remove assembled valve trip (70) and
the bench, then install through holes provided in air
fulcrum (71) from air piston by removing nuts (67)
cylinder, Fill oiler with recommended lubricant.
and packing (68). Disassemble the valve trip and
fulcrum by removing pin (69).
(2) Refer to paragraph 4-49 for installing pump.
(17) Disassemble the air piston (76) by removing
After installation, test pump for correct operation,
the clamp nut (72), muffler plate (73), nut (74), and
Refer to paragraph 2-8.
