JLG 680S, Service And Maintenance Manual

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SECTION 3 - CHASSIS & TURNTABLE
3-140 3121234
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
equipment to remove the bearing from the frame, then
move the bearing to a clean, suitably supported work
area.
Swing Bearing 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 spot with minimum gear backlash
(marked with yellow paint) is towards the centerline of
the swing drive (as close as the bolt pattern will allow).
JLG INDUSTRIES RECOMMENDS THAT ALL REMOVED BEARING BOLTS BE DIS-
CARDED AND REPLACED WITH NEW BOLTS. SINCE THE SWING BEARING IS THE
ONLY STRUCTURAL LINK BETWEEN THE FRAME AND TURNTABLE, IT IS IMPER-
ATIVE THAT SUCH REPLACEMENT HARDWARE MEETS JLG SPECIFICATIONS.
USE OF GENUINE JLG HARDWARE IS HIGHLY RECOMMENDED.
2. Apply a light coating of JLG Threadlocker P/N 0100019
to the new bearing bolts, and loosely install the bolts
and washers through the frame and outer race of bear-
ing.
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 3-74., Swing Bearing Torque Sequence. Spray a light
coat of Safety Solvent 13 on the new bearing bolts. Then
apply a light coating of JLG Threadlocker P/N 0100019
to the new bearing bolts, and install the bolts and wash-
ers through the frame and outer race of the bearing.
Tighten the bolts to a torque of 190 ft. lbs. (258 Nm) w/
Loctite.
4. Remove the lifting equipment from the bearing.
5. Using suitable lifting equipment, carefully position the
turntable assembly above the machine frame.
6. Carefully lower the turntable onto the swing bearing,
ensuring that the scribed line of the inner race of the
bearing aligns with scribed line on the turntable. If a
new swing bearing is used, ensure that the filler plug fit-
ting is at 90 degrees from the fore and aft center line of
the turntable.
7. Spray a light coat of Safety Solvent 13 on the new bear-
ing bolts. Then apply a light coating of JLG Threadlocker
P/N 0100019 to the new bearing bolts, and install the
bolts and washers through the turntable and inner race
of the bearing.
8. Following the Torque Sequence diagram shown in Fig-
ure 3-74., Swing Bearing Torque Sequence, tighten the
bolts to a torque of 190 ft. lbs. (258 Nm) w/Loctite.
9. Remove the lifting equipment.
10. Install the rotary coupling retaining yoke brackets, apply
a light coating of JLG Threadlocker P/N 0100011 to the
attaching bolts and secure the yoke to the turntable
with the mounting hardware.
11. Connect the hydraulic lines to the rotary coupling as
tagged prior to removal.
12. At ground control station, use boom lift control to lower
boom to stowed position.
13. Using all applicable safety precautions, activate the
hydraulic system and check the swing system for proper
and safe operation.
Swing Bearing Torque Values
1. Outer Race - 190 ft. lbs. (258 Nm) w/Loctite.
2. Inner Race - 190 ft. lbs. (258 Nm) w/Loctite.
3. See Swing Bearing Torquing Sequence.
CHECK THE INNER AND OUTER SWING BEARING BOLTS FOR MISSING OR
LOOSENESS AFTER FIRST 50 HOURS OF OPERATION, AND EVERY 600 HOURS
THEREAFTER.