T M 55-1730-221-12
d. Rap lightly with a soft-head mallet at inner bear-
3-1. SPECIAL TOOLS. No special tools are required
ing circumference to facilitate removal of bearings
for normal repair of the jack.
(35, 41, 46).
e. Do not remove extension screw (49) from third-
t h e jack according to the procedure set forth in para-
stage ram (44) unless either part is damaged. For-
graphs 3-3 and 3-4.
cible removal of extension screw (49) will damage
p l u n g e r (50), which with spring (51), internally limits
3 - 3 . REMOVAL OF VALVE ASSEMBLY. If removal of
s c r e w extension to a safe height.
t h e valve assembly (14) is necessitated, proceed as fol-
a. Tighten vent assembly (52) vent screw securely.
If damage necessitates removal of extension
b . Remove cotter pin (6) and straight headed pin (7)
screw (49) from third-stage ram (44), clamp
s e c u r i n g pump piston (8) to pump lever (5).
ram (44) in a vise, using wood blocks to pro-
tect outer ram surfaces. Unscrew extension
c . Stand jack on end, resting on reservoir to prevent
screw (49) forcibly, shearing internal plunger
excessive fluid loss, and unscrew pump cylinder (12)
Install new plunger and spring (51) in
with associated parts (8) through (11). Remove upper
hole in extension screw (49) prior to reassem-
valve copper gasket (13) from threaded hole in base
bling screw and third-stage ram (44).
assembly (56), if it has not come out with the pump cyl-
3-5. CLEANING. Wash parts with dry cleaning sol-
d . Screw a 1-1/2 inch long, 1/4-20UNC-2B screw into
vent, Federal Specification No. P-S-661, and dry
t h o r o u g h l y with a clean, lint-free cloth.
threaded hole atop valve body (21) and remove valve as-
For service and repair purposes, do not disas-
semble valve assembly (14) beyond the point
Use dry cleaning solvent only in a well-ven-
necessary for each service or repair problem.
t i l a t e d area. Avoid prolonged contact with skin,
R e m o v a l or rotation of adjusting screw (15) will
a n d inhalation of solvent vapors.
necessitate readjustment and testing of jack
by-pass pressure setting (refer to paragraphs
Inspect all parts for damage,
3-11a through 3-11c).
distortion, corrosion, and other faults as outlined in
3-4. DISASSEMBLY OF JACK ASSEMBLY. Disassem-
Figures 3-2 and 3-3.
ble the detail parts of the jack in the same order as the
k e y index numbers assigned to the exploded view, fig-
c e d u r e s shall be used to accomplish repair of the jack.
u r e 3-1, noting the following:
a. Remove handle (1). Unscrew vent assembly (52).
a. Defective ball seats in valve body (21) and base
Remove release valve (25), while simultaneously un-
a s s e m b l y (56) shall be refaced, using a standard valve
screwing lock screw (24). Remove ball (27).
seat facing tool.
Using a brass dowel, a mallet,
and a ball of the same size used with seat being re-
b. Pour hydraulic fluid from jack into a clean con-
f a c e d , form new seat by tapping lightly at seated ball
until a 1/64 inch wide seat is formed. Discard ball
used for seating operation. Wash refaced seat with
c. Do not disassemble valve assembly (14) unless
dry cleaning solvent, Federal Specification P-S-661,
defective valve operation indicates the necessity of
a n d dry thoroughly (refer to WARNING following para-
such disassembly (refer to Figure 2-2 and NOTE,
g r a p h 3 - 5 ) . I n s t a l l a new ball of proper size at each
following paragraph 3-3d).