JLG 120-SXJ ANSI Service Manual - Manual (Page 33)

SECTION 3 - CHASSIS & TURNTABLE
3121105 – JLG Lift – 3-5
3.2 SWING BEARING
Turntable Bearing Mounting Bolt Condition
Check
NOTE: This check is designed to replace the existing bear-
ing bolt torque checks on JLG Lifts in service. This
check must be performed after the first 50 hours of
machine operation and every 600 hours of machine
operation thereafter. If during this check any bolts
are found to be missing or loose, replace missing or
loose bolts with new bolts and torque to the value
specified in the torque chart, after lubricating the bolt
threads with loctite #271. After replacing and
retorquing bolt or bolts recheck all existing bolts for
looseness.
Check the frame to bearing. Attach bolts as follows:
1. Elevate the fully retracted boom to 70 degrees (full
elevation).
2. At the positions indicated on Figure 3-3., Swing
Bearing Bolt Feeler Gauge Check, try and insert the
0.0015" feeler gauge between the bolt head and
hardened washer at the arrow indicated position.
3. Assure that the 0.0015" feeler gauge will not pene-
trate under the bolt head to the bolt shank.
4. Swing the turntable 90 degrees, and check some
selected bolts at the new position.
5. Continue rotating the turntable at 90 degrees inter-
vals until a sampling of bolts have been checked in
all quadrants.
Check the turntable to bearing. Attach bolts as follows:
1. Elevate the fully retracted boom to 70 degrees (full
elevation).
2. At the positions indicated on Figure 3-3., Swing
Bearing Bolt Feeler Gauge Check, try and insert the
0.0015" feeler gauge between the bolt head and
hardened washer at the arrow indicated position.
3. Lower the boom to horizontal and fully extend the
boom.
4. At the position indicated on Figure 3-3., Swing Bear-
ing Bolt Feeler Gauge Check, try and insert the
0.0015" feeler gauge between the bolt head and
hardened washer at the arrow indicated position.
Bearing Wear Tolerance
1. From the underside of the machine, at rear center,
with the boom fully elevated and fully retracted (Fig-
ure 3-4., Swing Bearing Tolerance Boom Place-
ment), measure and record the distance between
the swing bearing and the frame using a magnetic
base dial indicator. (Figure 3-4., Swing Bearing Tol-
erance Boom Placement)
2. At the same point, with the boom at horizontal and
extended until red marking band on mid section is
exposed, measure and record the distance between
the swing bearing and frame using a magnetic base
dial indicator. (Figure 3-4., Swing Bearing Tolerance
Boom Placement)
3. If a difference greater than 0.064 in. (1.625 mm) is
determined, the swing bearing should be replaced.
4. If a difference less than 0.064 in. (1.625 mm) is
determined, and any of the following conditions
exist, the bearing should be removed, disassem-
bled, and inspected for the following:
a. Metal particles in the grease.
b. Increased drive power required.
c. Noise.
d. Rough rotation.
.0015" Feeler Gauge
Figure 3-3. Swing Bearing Bolt Feeler Gauge Check