JLG 600SC_660SJC Service Manual - Manual (Page 72)

SECTION 3 - CHASSIS & TURNTABLE
3-36 – JLG Lift – 3121607
Swing Bearing Replacement
REMOVAL
1. Operate boom from Ground Control station to provide
access to frame opening or 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 fittings on top
of 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
turntable weldment.
6. Use a suitable tool to scribe a line on swing bearing
inner race an underside of turntable. This will aid in
aligning bearing upon installation. Remove bolts and
washers which attach turntable to bearing inner race.
Discard bolts.
7. Use lifting equipment to carefully lift complete turntable
assembly from bearing. Ensure no damage occurs to
turntable, bearing, or frame-mounted components.
8. Carefully place turntable on a suitably supported trestle.
9. Use a suitable tool to scribe a line on outer swing bear-
ing race and frame. This line will aid in aligning bearing
upon installation. Remove bolts and washers which
attach outer race of bearing to frame. Discard bolts. Use
suitable lifting equipment to remove bearing from
frame, then move bearing to a clean, suitably supported
work area.
INSTALLATION
1. Using suitable lifting equipment, carefully lower swing
bearing in position on frame. Ensure scribed line of outer
bearing race aligns with scribed line on frame. If a new
swing bearing is used, ensure filler plug fitting is 90°
from fore and aft center line of 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.
CHECK TORQUE SETTING ACCURACY OF TOOL IF COMPRESSED AIR OR ELECTRI-
CALLY OPERATED IMPACT WRENCH IS USED TO TIGHTEN BEARING ATTACH-
MENT BOLTS.
2. Refer to Torque Sequence diagram as shown in Figure 3-
34., Swing Bearing Torque Sequence. Clean residue off
new bearing bolts and apply a light coating of Thread
Locking Compound JLG P/N 0100019. Install bolts and
washers through frame and outer bearing race. Torque
bolts to 190 ft-lb (258 Nm). Remove lifting equipment
from bearing.
3. Using suitable lifting equipment, carefully position turn-
table assembly above machine frame.
4. Carefully lower turntable onto swing bearing. Ensure
scribed line of inner bearing race aligns with scribed line
on turntable. If a new swing bearing is used, ensure filler
plug fitting is 90° fore and aft center line of turntable.
5. Clean residue off new bearing bolts and apply a light
coating of Thread Locking Compound JLG P/N 0100019.
Install bolts and washers through turntable and bearing
inner race.