JLG E300 Service Manual - Manual (Page 87)

SECTION 3 - CHASSIS & TURNTABLE
3121253 – JLG Lift – 3-53
Replacement of Swing Bearing
1. Removal.
a. Attach an adequate support sling to the boom
and draw all slack from sling. Prop or block the
boom if feasible.
b. Tag and disconnect hydraulic lines running
through center of turntable and frame. Use a
suitable container to retain any residual hydrau-
lic fluid. Cap lines and ports.
c. Attach suitable overhead lifting equipment to the
base of turntable weldment.
d. Use a suitable tool to scribe a line on the inner
race of the swing bearing and on the underside
of the turntable. This will aid in aligning the bear-
ing upon installation. Remove bolts, nuts and
washers which attach the turntable to the bear-
ing inner race. Discard nuts and bolts.
e. Use the lifting equipment to carefully lift the com-
plete turntable assembly from the bearing.
Ensure that no damage occurs to the turntable,
bearing or frame mounted components.
f. Carefully place the turntable on a suitably sup-
ported trestle.
g. 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 installa-
tion. Remove the bolts and washers which
attach the outer race of the bearing to the frame.
Discard the bolts. Use suitable lifting equipment
to remove the bearing and rotation box assem-
bly from the frame; move to a clean, suitably
supported work area.
h. Remove the two cap screws securing the bear-
ing to the rotation box to separate the two for
inspection.
2. Installation.
a. Install bearing to rotation box with two cap
screws, so that fill plug of bearing is as close to
gear as bolt pattern will allow. Do not tighten cap
screws.
b. Line up high spot (blue) of bearing as shown
below. Set backlash to 0.008 - 0.010 inch (0.20 -
0.25 mm). Tighten cap screws as shown in Fig-
ure 3-26., Swing Bearing Torque Sequence.
c. Grease bearing with Mobilith SHC Bearing
Grease. Grease fitting is remotely mounted.
d. Using suitable lifting equipment, install bearing/
rotation box assembly to frame with soft spot
(red) 90 degree relative to load axis. If reusing
old bearing, ensure that scribed line of outer
race of the bearing aligns with the scribed mark
on the frame.
JLG INDUSTRIES RECOMMENDS THAT ALL REMOVED GRADE 8
BEARING NUTS AND BOLTS BE DISCARDED AND REPLACED
WITH NEW NUTS AND BOLTS. SINCE THE SWING BEARING IS
THE ONLY STRUCTURAL LINK BETWEEN THE FRAME AND TURN-
TABLE, IT IS IMPERATIVE THAT SUCH REPLACEMENT HARD-
WARE MEETS JLG SPECIFICATIONS. USE OF GENUINE JLG
HARDWARE IS HIGHLY RECOMMENDED.
e. Apply a light coating of threadlocker JLG P/N
0100019 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.
POSITION POINT OF
MINIMAL BACKLASH
IN THIS AREA