37-1-614 Page 46
FIGURE 7-15 – BEARING SHIMS
FIGURE 7-16 – BEARING SHIMS
17. Lightly coat the shaft extension and bearing bore with oil. Assemble bearings (29, 30), as shown
in (FIGURE 7- 5, page 42), on the shaft. Assemble the press plate (refer to
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source not found.
, Disassembly page 36), on the bearing and install the jack screws, (FIGURE
7-17). Progressively tightening nuts on the jack screws presses bearings in place. To prevent
possible damage to the bearings and threads on the shaft, press one bearing over the shaft into
the shaft, press one bearing over the shaft into the bore at a time, rather than with both bearings
stacked together. When the first bearing is flush with the top face of the bore, the second bearing
may be started. Tighten nuts on the jack screws evenly to prevent cocking of the bearings on the
shaft and in the bore.
NOTICE
It is not recommended to hammer bearings of this size in place.
18. Install the bearing clamp plate (11, 12) and four “nylok” type screws, (FIGURE 7-18). Install lock
washer (35, 36) and spanner type nut (33, 34) on the main rotor shaft and drive up tight. This
operation pulls the rotor shaft through the bearings until the shims and bearing spacer are
clamped solidly between the rotor end and bearing, assuring a fixed position of the rotor.
This is
an important step in assembly
. The best method for tightening the nuts is with a wrench of the
type shown in
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, Disassembly page
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defined.
. Tighten the main rotor nut (33) to
130-150 ft-lb and tighten the gate rotor nut (34) to 64-90 ft-lb.
Making sure the bearings are properly seated, measure the height the outer race of the main
rotor bearing (30) extends above the bearing carrier surface (5) with a depth micrometer.
Measure the height in at least four places around the circumference of the outer race. Establish
required shim thickness under the main rotor bearing retainer (12) by taking the average of the
measurements and subtracting 0.002” from the average measured height. (Required Shim
Thickness = Average Measured Height – 0.002”). Select a maximum of four shims from the shim
kit (94) as required to obtain the required calculated shim stack thickness at each screw location.
Using a micrometer, measure each stacked thickness to insure the thickness is within
+0.000/-0.001 of the required calculated thickness for each screw location. Install main rotor
bearing retainer (12) with the required shim stack between the bearing retainer and the bearing
carrier at each of the four “Nylok” type screw (45) locations. Tighten screws to 51-58 ft-lb.
Install bearing retainer plate (11) on the gate rotor with the four “Nylok” type screws (45). Tighten
screws to 51-58 ft-lb.
