General Information 117 Section 5
IMT 5005i / 6006i - Manual # 99904387
Turntable Bearing Inspection
Turntable bearings may experience wear. One of the following conditions may indicate turntable bearing
1. Metal particles present in the bearing lubricant.
2. Increased drive power required to rotate the crane.
3. Noise emitting from the bearing during rotation.
4. Rough rotation.
5. Uneven or excessive wear between the pinion gear and turntable gear.
If one or more of the above conditions exists, further inspection may be required. Limits are measured
in “TILT” which is dependent on the internal clearances of the bearing. TILT is the most practical deter-
mination of a bearings’ internal clearance once mounted on a crane. You can measure the tilt using the
Turntable Bearing Tilt Test. (see “Turntable Bearing Tilt Test” listed below)
Periodic readings indicating a steady increase in TILT may be an indicator of bearing wear. Note that a
bearing found to have no raceway cracks or other structural irregularities should be reassembled and
returned to service.
Turntable Bearing Tilt Test
1. Place crane in vertical position.
2. Set a dial indicator at 0 on the pinion cover plate at back side of mast.
3. Lower crane to the horizontal position.
4. Check and record the dial indicator change. It should not exceed the tilt measurement noted in
the chart below.
5. Return the crane to the vertical position. The dial indicator should return to 0.
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