Wear Tolerance; Swing Bearing Removal - JLG 1200SJP Service Maintenance Manual

SECTION 3 - CHASSIS & TURNTABLE
Figure 3-56. Swing Bolt Feeler Gauge Check

Wear Tolerance

1. From the underside of the machine, at rear center, with
the main boom fully elevated and fully retracted, as
shown in Figure 3-54., Swing Bearing Tolerance Boom
Placement - Sheet 1 of 2, set up a magnetic base dial
indicator as shown below and set the indicator to 0
(zero).
2. Next, position the main boom fully extended and hori-
zontal as shown in Figure 3-55., Swing Bearing Tolerance
Boom Placement - Sheet 2 of 2. Read the measurement
recorded on the dial indicator gauge.
3-102
3. If the measurement is greater than 0.094 in. (2.387 mm),
the swing bearing should be replaced.
4. If the measurement is less than 0.094 in. (2.387 mm), and
any of the following conditions exist, the bearing should
be removed, disassembled, and inspected for the fol-
lowing:
a. Metal particles in the grease.
b. Increased drive power required.
c. Noise.
d. Rough rotation.
5. If bearing inspection shows no defects, reassemble and
return to service.

Swing Bearing Removal

1. From Ground Control station, operate the boom ade-
quately to provide access to frame opening 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 the boom and draw
all slack from sling. Prop or block the boom if feasible.
HYDRAULIC LINES AND PORTS SHOULD BE CAPPED IMMEDIATELY AFTER DIS-
CONNECTING LINES TO AVOID THE ENTRY OF CONTAMINANTS INTO THE SYS-
TEM.
3. Tag and disconnect the hydraulic lines from the fittings
on the top of the rotary coupling. Use a suitable con-
tainer to retain any residual hydraulic fluid. Immediately
cap lines and ports.
HYDRAULIC LINES AND PORTS SHOULD BE CAPPED IMMEDIATELY AFTER DIS-
CONNECTING LINES TO AVOID THE ENTRY OF CONTAMINANTS INTO THE SYS-
TEM.
4. From inside turntable, remove mounting hardware
which attach rotary coupling retaining yoke brackets to
turntable.
– JLG Lift – 3121142