TM 1-1520-238-23
2-312
Change 4
2.88.
ROTOR SUPPORT MAST SUPPORT BASE REMOVAL/INSTALLATION – continued
WARNING
The surface of the transmission cover and the mast base with the geared curvic coupling are
precise surfaces. Normal handling of aluminum parts do not apply. Do not abrade surfaces of
the curvic teeth over any extensive area. Small material movements can cause the curvic
surfaces to fail to mesh. If the curvic shows impact damage as would be caused by tool impact
or rough handling, remove any displaced metal to the surface. If the surface is corroded, send
the parts to depot maintenance. Mast base curvic coupling must be entirely free of debris,
displaced metal, and burrs.
NOTE
Position mast base on struts so that one mixer pivot support faces forward, and the other support
faces right side of helicopter.
Nuts may be reused if run-on torque exceeds 50 INCH-POUNDS.
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