SECTION 3 - CHASSIS & TURNTABLE
3-58
31215031
Swing Bearing Replacement
REMOVAL
1.
From Ground Control station, operate the boom ade-
quately to provide access to frame opening or, if
equipped, to rotary coupling.
NEVER WORK BENEATH THE BOOM WITHOUT FIRST ENGAGING BOOM SAFETY
PROP OR PROVIDING ADEQUATE OVERHEAD SLING SUPPORT AND/OR BLOCK-
ING.
2.
Attach an adequate support sling to boom and draw all
slack from sling. Prop or block boom if feasible.
3.
From inside turntable, remove mounting hardware
attaching rotary coupling retaining yoke brackets to
turntable.
HYDRAULIC LINES AND PORTS SHOULD BE CAPPED IMMEDIATELY AFTER DIS-
CONNECTING LINES TO AVOID THE ENTRY OF CONTAMINANTS INTO THE SYS-
TEM.
4.
Tag and disconnect hydraulic lines from the fittings on
the top of the rotary coupling. Use a suitable container
to retain any residual hydraulic fluid. Immediately cap
lines and ports.
5.
Attach suitable overhead lifting equipment to base of
the turntable weldment.
6.
Use a suitable tool to scribe a line on the inner race of
the swing bearing and on the underside of the turnta-
ble. This will aid in aligning the bearing upon installa-
tion. Remove the bolts and washers which attach the
turntable to the bearing inner race. Discard the bolts.
7.
Use the lifting equipment to carefully lift the complete
turntable assembly from the bearing. Ensure that no
damage occurs to the turntable, bearing or frame-
mounted components.
8.
Carefully place the turntable on a suitably supported
trestle.
9.
Use a suitable tool to scribe a line on the outer race of
the swing bearing and the frame. This line will aid in
aligning the bearing upon installation. Remove the bolts
and washers which attach the outer race of the bearing
to the frame. Discard the bolts. Use suitable lifting equip-
ment to remove the bearing from the frame, then move
the bearing to a clean, suitably supported work area.
INSTALLATION
1.
Using suitable lifting equipment, carefully lower the
swing bearing into position on the frame. Ensure the
scribed line of the outer race of the bearing aligns with
the scribed line on the frame. If a new swing bearing is
used, ensure that the filler plug fitting is at 90 degrees
from the fore and aft center line of the frame.
JLG INDUSTRIES RECOMMENDS ALL REMOVED BEARING BOLTS BE DISCARDED
AND REPLACED WITH NEW BOLTS. SINCE THE SWING BEARING IS THE ONLY
STRUCTURAL LINK BETWEEN THE FRAME AND TURNTABLE, IT IS IMPERATIVE
SUCH REPLACEMENT HARDWARE MEETS JLG SPECIFICATIONS. USE OF GENU-
INE JLG HARDWARE IS HIGHLY RECOMMENDED.
2.
Apply a light coating of High Strength Threadlocking
Compound to the new bearing bolts, and loosely install
the bolts and washers through the frame and outer race
of bearing.
IF COMPRESSED AIR OR ELECTRICALLY OPERATED IMPACT WRENCH IS USED
FOR TIGHTENING THE BEARING ATTACHMENT BOLTS, THE TORQUE SETTING
ACCURACY OF THE TOOL SHOULD BE CHECKED PRIOR TO USE.
3.
Refer to the Torque Sequence diagram as shown in Fig-
ure 3-58., Swing Bearing Torque Sequence Clean any res-
idue off the new bearing bolts, then apply a light coating
of High Strength Threadlocking Compound and install
the bolts and washers through the frame and outer race
of the bearing. Tighten the bolts to an initial torque of
190 ft. lbs. (260 Nm) w/Threadlocking Compound.
4.
Remove the lifting equipment from the bearing.
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