ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL
Rev.
7
MM-9-26
Aug
22/16
(7) Insert bolts in upper spline adapter (12) as guides and install spline adapter into
upper hub plate (14).
NOTE:
To distinguish between spline adapters, the upper spline adapter (12)
has the wider flat surface on top side of splines while the lower spline
adapter has a rib extending from lower end of spline.
(8)
Carefully turn hub assembly over and position on wood blocks.
(9) Install the lower spline adapter (18) (aligning the phasing mark with the upper
adapter phasing mark) into lower hub plate (17).
(10) Install center hub bolts (11) in holes adjacent to walking beam bracket mount holes
and install washers and nuts. Torque bolts.
(11) Install walking beam brackets (3) and secure with bolts (1 and 2). Torque bolts (1)
and safety with 0.032 safety wire. Torque bolts (2).
(12) To set rotational drag of U-blocks (15), proceed as follows:
(a)
Place hub assembly on a stand with lower end of U-blocks up.
(b)
Install DU washer (7) into recess of hub plate with chamfer in board toward hub
plate.
(c) Install approximately 0.025 shims (8) and lower U-block nut (9). Using tool T-
0003, torque nut to 50 ft-lbs/67.8 Nm.
(d) Rotate U-block to one of the stops and install a hinge pin partially into bearing
until it extends 4.75 in/12.1 cm.
(e)
Attach a spring scale to head of hinge pin and pull to check drag of U-block.
NOTE:
Drag tolerance with nut torqued is 4 to 10 lbs/1.8 to 4.5 kg.
(f)
Add or subtract shims (8) until proper drag torque is obtained.
NOTE:
Nut (9) must be torqued before checking drag.
(g) Place locking key (10) into slot of nut (9) aligned with notch in U-block and
secure key with screw.
(h)
Adjust drag of all three U-blocks following steps (b) through (g).
(13) Turn hub assembly over on stand.
(14) Install upper U-block nuts (5) as follows:
(a)
Install lockwasher (6) and nut (5) on U-block.
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