(1) Support boom hoist drum (17) with a suitable
sling and slide it off shaft (45) as an assembly. Items (1),
Sprockets (39) and (43) are match marked
(3) through (14), (2), (15) and (18) will come off the shaft
during manufacture and must be installed in
with the drum.
matched pairs. Be sure both sprockets have the
(2) At the opposite end of the boom hoist shaft,
same number stamped on the outer face. Be
remove lockwire (19), screws (20), keeper plate (21),
sure that the match marked internal spline
sprocket (22), packing (23) and spacer (24).
each sprocket mates properly with the marked
(3) Place suitable blocking beneath each end of
splines on the shaft.
the shaft to prevent the shaft from dropping during the
(4) Install spacers (38) and (42) Warm the inner
following procedure. Remove bearing retainer (27) and
races of bearings (35) and (36) and install the races on
(28) by removing screws (25) and lock washers (26) at
each end of the shaft. The races must be pressed firmly
each retainer. Oil seals (29) and (30) will come out in the
into place in one motion and must bear against spacers
(38) and (42) to form a solid assembly.
(4) Remove nuts (31) and lock washers (32) and
(5) Install the assembled shaft in the bore in the
remove bearing retainers (33) and (34). Two tapped
revolving frame and block it firmly in position with the
puller holes are provided in the bearing retainer to
shaft centered in the bore. Worm wheel must be
engaged in the worm shaft.
(5) Remove inner races of bearings (35) and (36)
(6) Install the outer races of bearing (35) and (36)
from the shaft using a suitable puller.
in bearing retainers (33) and (34) Install bearing re-
(6) Remove sufficient blocking from each end of
tainers on shaft (45) and secure with nuts (31) and lock
the shaft to disengage the worm wheel (37) from the
washers (32) on each bearing retainer.
worm shaft. All remaining items on the shaft can then be
(7) Assemble oil seals (29) and (30) into retainers
removed by sliding the shaft through the right side of the
(27) and (28). Be sure the seals are installed with the
springs facing sprockets (39) and (43) and that the areas
between the seal lips are packed with the GAA lubricant.
Do not disassemble worm wheel assembly(37)
Check seal surfaces of the shaft for nicks and bus. Minor
imperfections on the shaft can cause rapid seal wear.
(8) Install shims (46), (47) and (48) in equal
5-22. Cleaning, Inspection and Repair
amounts between bearing retainers (27) and (28), and
Clean all metal parts with cleaning solvent, Federal
retainers (33) and (34) so that shaft end play is between
Specification P-D-680, or equivalent, before inspecting.
0.003 and 0.005 inch, using a dial indicator. Install the
Inspect all parts for wear, scoring, cracks, or any other
two bearing retainers (27) and (28) using screws (25)
visible signs of damage, and replace all parts not in good
and lock washers (26).
condition. Replace all packing, seals, bearings, gaskets,
(9) Adjust worm wheel-worm shaft backlash as
deformed shims, and other expendable items. Inspect
the parts listed in table 1-4 for conformity with maximum
(a) Turn the worm shaft through one complete
clearances and replace any part worn beyond the
maximum dimensions listed. Adjust end play by
(b) Check points of contact between the worm
shimming, if necessary, and maintain the tolerances
and worm wheel (37). Under no load conditions, all
contact must be to the left of the center of the worm
5-23. Reassembly and Installation
a. The boom hoist shaft is reassembled in place as it
is installed in the machine.
Tooth contact must be checked by removing the
inspection plate, and it must be checked at the
The worm shaft must be installed before the
bottom of the worm wheel.
boom hoist shaft can be installed.
(c) If all contact is not on the left side of the
(1) Install key (41) and press worm wheel
worm shaft, move shims (46), (47) and (48) as required
assembly (37) on shaft (45). The faces of wheel
to a point beneath the opposite bearing retainer until
assembly (37) must be flush with the shaft (45) shoulder.
proper contact is accomplished. Then recheck boom
(2) Coat worm wheel teeth (37) with a light coat-
hoist shaft end play.
ing of white lead of Prussia blue. This is used later to
(d) Use a suitable sealing compound, such as
adjust the worm wheel-to-worm shaft gear contact. The
Permatex No. 2 on screws (25) and lock washers (26)
finished face of the worm wheel must be placed on the
and adjacent sealing surfaces.
right side, as viewed from the rear of the shaft.
(10) Assemble the boom hoist drum (17) as
(3) Install spacers (40) and (44) and sprockets
(39) and (43). The sprockets must be tight against the
(a) Position drum (17) on the workbench, with
ratchet side up. Pack drum with grease, type GAA, as
described in the current LO 5-3810-295-12 (series).