JLG 450A_AJ Series II Service Manual - Manual (Page 268)

SECTION 4 - BOOM & PLATFORM
4-2 – JLG Lift – 3121180
Disassembly of Main Boom
1. Loosen jam nuts on aft end of fly boom wear pad
adjustment and loosen adjustments.
2. Using a portable power source, attach hose to tele-
scope cylinder port block. Using all applicable
safety precautions, activate hydraulic system and
extend cylinder to gain access to cylinder rod retain-
ing pin. Shut down hydraulic system.
3. Carefully disconnect hydraulic hose from retract port
of cylinder. There will be initial weeping of hydraulic
fluid which can be caught in a suitable container.
After initial discharge, there should be no further
leakage from the retract port.
4. Remove hardware securing telescope cylinder to
the fly boom section, then remove pin from fly.
5. Remove hardware securing telescope cylinder to
the base boom section.
WHEN REMOVING TELESCOPE CYLINDER FROM BOOM SEC-
TIONS. CARE SHOULD BE TAKEN NOT TO LEAVE CYLINDER REST
ON POWERTRACK WHICH COULD CAUSE DAMAGE TO POW-
ERTRACK.
6. Using a suitable lifting device, remove telescope cyl-
inder from boom sections.
7. Using a piece of tape, mark length of hoses and
wires from front of fly boom and bottom of base
boom for reassembly.
8. Remove hardware securing front wear pads on base
boom section. Remove wear pads.
9. Remove hardware securing powertrack to aft end of
fly boom section.
10. Using a suitable lifting device, remove fly boom from
boom section.
11. Remove hydraulic lines and electrical cables from
powertrack.
12. Remove hardware securing powertrack to base
boom section. Remove powertrack.
Inspection
1. Inspect all boom pivot pins for wear, scoring or other
damage, and tapering or ovality. Replace pins as
needed.
2. Inspect lift cylinder pins for wear, scoring or other
damage, and for tapering or ovality. Ensure pin sur-
faces are protected prior to installation. Replace pins
as needed.
3. Inspect telescope cylinder rod attach pin for wear,
scoring or other damage. Replace pin as needed.
4. Inspect inner diameter of boom pivot bushings for
scoring, distortion, wear or other damage. Replace
bushings as needed.
5. Inspect wear pads for wear.
6. Inspect all threaded components for damage such
as stretching, thread deformation, or twisting.
Replace as needed.
7. Inspect structural units of boom assembly for bend-
ing, cracking, separation of welds, or other damage.
Replace boom sections as needed.