TM 9-4940-568-34
3-17
This task covers:
a. Inspection
b. Follow-On Maintenance
INITIAL SETUP
Equipment Condition
FRS unloaded (TM 9-4940-568-10)
FRS system leveled (including cribbing
if necessary) on hard, level ground,
with crane erected, (TM 9-4940-568-10)
Ensure turntable bearing is lubricated,
(TM 9-4940-568-10)
Ensure all turntable mounting bolts have
been tightened to recommended torque
value, (Para 3-29)
Tools and Special Tools
Tool Kit, General Mechanic’s
(Item 67, Appendix F)
Indicator, Dial, Set (Item 33, Appendix F)
Protractor, Magnetic (Item 41, Appendix F)
Sander, Portable, Disk Electric (Item 48, Appendix F)
3-6. TURNTABLE BEARING INSPECTION PROCEDURE.
References
TM 9-4940-568-10
a.
Inspection.
Do not stand under crane. Mechanical failure and operator error can cause injury or
death to personnel.
NOTE
To obtain a true reading of bearing vertical movement, the dial indicator and magnetic
base must be positioned correctly. Perform the steps below.
Ensure that the plunger is straight up and down in all directions, front to back and side to
side. It is not necessary to measure this, but try to get it as close as possible with a visual
inspection from different angles.
Ensure that the dial indicator is pre-loaded at least one turn by allowing the needle to
complete one turn around the dial before zeroing the dial.
Ensure that the magnetic base is secure at its attachment point so it will not move and
contribute to a false indicator reading.
The dial indicator must be in line with the axial centerline of the boom for all
measurements.
To give a consistent reading, the dial indicator plunger must be as close as possible to the
outside diameter of the swing gear tooth tip, as the allowable bearing movement only
applies at the tip of the gear tooth. The indicator reading will be magnified if the plunger
contact point is off of the outer diameter of the swing gear tooth tip.
Always verify that the dial indicator reading is correct by lowering the boom from the 60
degree boom angle to the level boom angle, then check that the dial indicator returns to the
zero position. Repeat the procedure if the dial indicator does not return to the zero
position.
