Replacement Of Swing Bearing - JLG E450A Service And Maintenance Manual

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.

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 con-
tainer to retain any residual hydraulic 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 bearing upon
installation. Remove bolts, nuts and washers which
attach the turntable to the bearing inner race. Dis-
card 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 installation. Remove
the bolts and washers which attach the outer race of
the bearing to the frame. Discard the bolts. Use suit-
able lifting equipment to remove the bearing and
rotation box assembly from the frame; move to a
clean, suitably supported work area.
h. Remove the two capscrews securing the bearing to
the rotation box to separate the two for inspection.
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SECTION 3 - CHASSIS & TURNTABLE
2. Installation.
a. Install bearing to rotation box with two capscrews,
so that fill plug of bearing is as close to gear as bolt
pattern will allow. Do not tighten capscrews.
b. Line up high spot (blue) of bearing with center
tooth of worm gear. Set backlash to 0.008 - 0.010
inch (0.20 - 0.25 mm). Tighten capscrews as shown
in Figure 3-24., Swing Bearing Torquing Sequence.
c. Apply Tribol Molub-Alloy 936 Open Gear Com-
pound to bearing and worm gear teeth.
d. Grease bearing with Mobilith SHC Bearing Grease.
Grease fitting is on inside wall of inner race of bear-
ing.
NOTE: If Tribol Molub-Alloy 936 Open Gear Compound or Mobil-
ith SHC Bearing Grease are not available, Multi-Purpose
Grease (MPG) can be substituted, however the service inter-
val will be shorter.
e. Using suitable lifting equipment, install bearing/
rotation box assembly to frame with soft spot (red)
90 degrees relative to load axis. If reusing old bear-
ing, 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 TURNTABLE, IT IS IMPERATIVE THAT SUCH REPLACEMENT HARD-
WARE MEETS JLG SPECIFICATIONS. USE OF GENUINE JLG HARDWARE IS
HIGHLY RECOMMENDED.
f. Apply a light coating of JLG Threadlocker PN
0100019 to the new bearing bolts and loosely install
the bolts and washers through the frame and outer
race of bearing.
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