JLG 340AJ Service Manual - Manual (Page 96)

SECTION 3 - CHASSIS & TURNTABLE
3-56 – JLG Lift – 3121259
Turntable Bearing Mounting Bolt Condition Check
NOTE: This check is designed to replace the existing bearing 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 lubri-
cating 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 ele-
vation).
2. At the positions indicated on the figure titled Swing
Bearing Tolerance Boom Placement. Try and insert the
0.0015" feeler gauge between the bolt head and hard-
ened washer at the arrow indicated position.
3. Assure that the 0.0015" feeler gauge will not penetrate
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 intervals
until a sampling of bolts have been checked in all quad-
rants.
Check the turntable to bearing. Attach bolts as follows:
1. Elevate the fully retracted boom to 70 degrees (full ele-
vation).
2. At the positions indicated in the figure below, 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 2-30. try and insert
the 0.0015" feeler gauge between the bolt head and
hardened washer at the arrow indicated position.
Wear Tolerance
1. With the boom positioned over the side of the machine,
the Upper Boom horizontal with telescope fully
extended and Mid/Lower Boom stowed, using a mag-
netic base dial indicator, measure and record the dis-
tance between the swing bearing and turntable.
2. At the same point, with the boom positioned over the
side of the machine, the Upper Boom fully elevated and
the Mid/Lower Boom fully elevated, using a magnetic
base dial indicator, measure and record the distance
between the swing bearing and turntable.
3. If a difference greater than 0.057 in. (1.40 mm) is deter-
mined, the swing bearing should be replaced.
4. If a difference less than 0.057 in. (1.40 mm) is deter-
mined, and any of the following conditions exist, the
bearing should be removed.
a. Metal particles in the grease.
b. Increased drive power.
c. Noise.
d. Rough rotation.
5. If bearing inspection shows no defects, reassemble
bearing and return to service.
Swing Bearing Torque Value
Install bolts with JLG Threadlocker P/N 0100019; Torque to 133
ft.lbs. (180 Nm).
.0015" Feeler Gauge
Figure 3-34. Swing Bearing Feeler Gauge Check
SWING
BEARING
FRAME REF.
TURNTABLE REF.
MEASURING
POINT
Figure 3-35. Swing Bearing Tolerance Measuring Point