JLG 660SJ Service Manual - Manual (Page 95)

SECTION 3 - CHASSIS & TURNTABLE
3121202 – JLG Lift – 3-45
3.8 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.
1. Check the frame to bearing. Attach bolts as follows:
a. Elevate the fully retracted boom to 70 degrees
(full elevation).
b. At the positions indicated on Figure 3-42. try and
insert the 0.0015" feeler gauge between the bolt
head and hardened washer at the arrow indi-
cated position.
c. Assure that the 0.0015" feeler gauge will not
penetrate under the bolt head to the bolt shank.
d. Swing the turntable 90 degrees, and check
some selected bolts at the new position.
e. Continue rotating the turntable at 90 degrees
intervals until a sampling of bolts have been
checked in all quadrants.
2. Check the turntable to bearing. Attach bolts as fol-
lows:
a. Elevate the fully retracted boom to 70 degrees
(full elevation).
b. At the positions indicated on Figure 3-42. try and
insert the 0.0015" feeler gauge between the bolt
head and hardened washer at the arrow indi-
cated position.
c. Lower the boom to horizontal and fully extend
the boom.
d. At the position indicated on Figure 3-42. try and
insert the 0.0015" feeler gauge between the bolt
head and hardened washer at the arrow indi-
cated position.
Wear Tolerance
1. From the underside of the machine, at rear center,
with the boom fully elevated and fully retracted, as
shown in Figure 3-43., Swing Bearing Tolerance
Boom Placement - Swing Bearing Tolerance Boom
Placement) A, using a magnetic base dial indicator,
measure and record the distance between the swing
bearing and turntable. (Figure 3-44., Swing Bearing
Tolerance Measuring Point)
2. At the same point, with the boom at horizontal and
fully extended, and the tower boom fully elevated as
shown in - Swing Bearing Tolerance Boom Place-
ment) B, using a magnetic base dial indicator, mea-
sure and record the distance between the swing
bearing and turntable. (Figure 3-44., Swing Bearing
Tolerance Measuring Point)
3. If a difference greater than 0.079 in. (2.00 mm) is
determined, 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 the grease.
b. Increased drive power required.
c. Noise.
d. Rough rotation.
.0015" Feeler Gauge
Figure 3-42. Swing Bearing Bolt Feeler Gauge Check