SUBSECTION 8C
BOOM HOIST SHAFTS
2. Position drum (34) with the ratchet side up, and pack the
C. If all contact is not on the left side of the worm, shift
shims from beneath the two oil seal retainers until this
drum with grease. See Section III for the recommended
contact is properly established. Note that the proper
grease (P&H Number 472).
3. Turn the drum and complete packing the drum cavity
1, which is a view from the rear of the shaft.
with grease.
4. Pack bearings (55 and 21) with grease and install seal
13. With proper worm-to-worm wheel contact estab-
(58) in bearing (21). Press the bearings into the bore of drum
lished, install retainers (06 and 23). Apply Permatex No. 2 to
(34) until each one is snug against the shoulders in the
capscrews (09 and 25) threads, and to the adjacent sur-
drum bore.
faces.
14. Place new O-ring (05) in spacer (04) and assemble to
5. Install seal (38) in position in the drum, if the seal has
the boom hoist shaft.
been removed. Always pack the seal with grease and be
sure the sealing lip and spring face inward toward pinions
15. Install spacer (22) on the shaft and slide drum (34) with
(52).
bearing (21) firmly seated against it.
6. Press worm wheel (30) hub onto shaft (33). The worm
16. Install spacer (28), then slide drum (56) onto the shaft.
wheel hub faces must be flush with the shaft shoulders.
Then install spacers (31) and sprockets (29). The sprocket
17. Install pinions (52) in drum (56). Lubricate O-rings (51)
should be tight against the spacers.
and install them on pins (54). Install pins (54) in pinions (52).
Turn the pins so that the flats on the outer ends of the pins
NOTE
will allow bearing retainer (48) to be installed.
Sprockets (29) are match marked during manufac-
18. Install spacer (36) and slide sun gear (50) onto the
ture and must be installed in matched pairs. Be sure
shaft. Then install spacer (46) followed by O-ring (47).
that both sprockets have the same number stamped
19. Pack the cup of bearing (49) with grease and press it
on the outer edge. The match marked internal spline
into retainer (48). Then place the retainer onto the shaft and
on the sprockets must line up with the marked splines
install the bearing cone into the bearing cup.
on the shaft.
20. Place the assembly tool (218T1470) as shown in Fig-
Also, paint the worm wheel with a coat of white lead
ure 8C-2, onto the shaft and secure in place with washer
or Prussian blue, This will be used later to adjust the
(41) and nut (39).
worm gear to worm wheel contact.
NOTE
7. Install the boom hoist shaft in the chain case bore and
block it securely in position, with the shaft centered in the
Do not install shims (53) at this time. Also, assembly
bore, and the worm wheel engaged in the worm shaft.
tool (218T1470) may be fabricated using the dimen-
sions shown on the illustration
8. Apply No. 2 Permatex on the points indicated in Figure
8C-1. Install gaskets (14 and 17) in retainers (11 and 27). In-
stall the retainers and secure them in positron with the lock-
21. Install and tighten snugly the capscrews that hold bear-
washers and nuts.
ing retainer (48) in place. Clamp the two drums together to
keep preload pressure on bearing (35).
9. Install seals (08 and 20) into retainers (06 and 23). Be
sure the seals are installed with the springs facing the
22. Attach a dial indicator to the shaft and set the tip
sprockets, and that the areas between the seal lips are
against the flat surface of the retainer. Take a reading, then
packed with grease. Check the seal seating surface on the
remove the capscrews and pull out on the retainer. Take
shaft for nicks or burrs, since minor imperfections on the
another reading of the indicator and subtract the two read-
shaft surfaces can cause rapid wear on the seals.
ings to obtain the total clearance which is the total end play
of the bearings.
10. Pack bearings (15 and 16) with multipurpose grease
as recommended in Section Ill.
NOTE
11. Install sufficient shims (07 and 24) between bearing re-
As an example, if the total clearance measuredabove
tainers (06 and 23). so that shaft end play is 0.003 to 0.005
was 0.028, and the desired bearing preload is 0.003
inch. Temporarily fasten the two retainers for the check in
inch, then the amount of shims required should mea-
step 12.
sure 0.025 inch.
12. Adjust the worm-to-worm wheel contact by shifting
23. Remove the dial indicator, nut (39). washer (41). the as-
shims from beneath one retainer to the other as follows:
sembly tool, capscrews (42) and retainer (48) with bearing
(49) included.
A. Turn the worm through one complete revolution.
24. Following the example in the note above, determine the
B. Check the point of contact between the worm and the
amount of shims required and install them between re-
worm shaft as shown in Figure 8C-1. It is most
tainer (48) and drum (56). Bear in mind the desired bearing
important that all contact, under no load conditions, be
preload is 0.003 inch.
to the left of the vertical centerline of the worm shaft.
8C-2