JLG 1250AJP Service Manual - Manual (Page 146)

SECTION 3 - 1CHASSIS & TURNTABLE
3-98 – JLG Lift – 3121171
3.20 SWING BEARING
Turntable Bearing Mounting Bolt Condition
Check
THE SWING BEARING IS ONE OF THE MOST CRITICAL POINTS ON
AN AERIAL LIFT. 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 OPERATION.
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 applying loctite
#271 to the bolt threads. After replacing and retorqu-
ing bolt or bolts recheck all existing bolts for loose-
ness.
1. Check the frame to bearing attach bolts as follows:
a. Fully elevate the main boom with the tower fully
lowered. (See Figure 3-52.)
b. At the position indicated on Figure 3-52., try to
insert a 0.0015 feeler gauge between the bolt
and hardened washer at the arrow indicated
position.
c. Ensure 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 main boom to full ele-
vation.
b. At the position indicated on Figure 3-54. try to
insert the 0.0015” feeler gauge between the bolt
head and hardened washer at the arrow indi-
cated position.
c. Fully raise and extend the tower boom.
d. Lower the main boom to horizontal and fully
extend the boom.
e. At the position indicated on Figure 3-53., try and
insert the 0.0015” feeler gauge between the bolt
head and hardened washer at the arrow indi-
cated position.