SECTION 3 - CHASSIS & TURNTABLE
3-56
31215031
Wear Tolerance
1.
From underside of the machine, at rear center, with the
tower boom fully elevated and fully retracted, as shown
in Figure 3-58. Swing Bearing Tolerance Measurement
Location & Boom Placement A, using a magnetic base
dial indicator, measure and record distance between
swing bearing and turntable as shown in Figure 3-57.
Swing Bearing Tolerance Measuring Point.
2.
At the same point, with the main boom horizontal and
fully extended, and the tower boom fully elevated as
shown in the Figure 3-58. Swing Bearing Tolerance Mea-
surement Location & Boom Placement B, using a mag-
netic base dial indicator, measure and record distance
between swing bearing and turntable as shown in Fig-
ure 3-57. Swing Bearing Tolerance Measuring Point.
3.
If difference is greater than 0.079 in. (2.00 mm), is deter-
mined, the swing bearing should be replaced.
4.
If a difference less than 0.079 in. (2.00 mm) is deter-
mined, and any of the following conditions exist, the
bearing should be removed, disassembled, and
inspected for the following:
a.
Metal particles in grease.
b.
Increased drive power required.
c.
Noise.
d.
Rough rotation.
5.
If bearing inspection shows no defects, reassemble and
return to service.
THE SWING BEARING IS ONE OF THE MOST CRITICAL POINTS ON MOBILE ELE-
VATING WORK PLATFORM. IT IS HERE THAT THE STRESSES OF LIFTING ARE
CONCENTRATED, AT THE CENTER OF ROTATION. BECAUSE OF THIS, PROPER
MAINTENANCE OF THE SWING BEARING BOLTS IS A MUST FOR SAFE OPERA-
TION.
Figure 3-57. Swing Bearing Tolerance Measuring Point
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