JLG E300 Service Manual - Manual (Page 99)

SECTION 4 - BOOM & PLATFORM
3121253 – JLG Lift – 4-1
SECTION 4. BOOM & PLATFORM
4.1 BOOM MAINTENANCE
Removal of the Main Boom
HYDRAULIC LINES AND PORTS SHOULD BE CAPPED IMMEDI-
ATELY AFTER DISCONNECTING LINES TO AVOID ENTRY OF CON-
TAMINANTS INTO SYSTEM.
1. Raise the boom to a horizontal position.
2. Place blocking in the tower boom for support and
prevent it from lowering.
NOTE: The jib/platform assembly weighs approximately 500
lbs. (230 kg).
3. Support the weight of the jib/platform assembly
using adequate lifting or blocking equipment.
NOTE: The main boom assembly weighs approximately 475
lbs. (216 kg).
4. Support the weight of the main boom with an ade-
quate lifting device.
5. Tag and disconnect all electrical lines running to the
platform.
6. Tag and disconnect all hydraulic lines running to the
plaform rotator, jib rotator (if equipped), and jib cylin-
der. Cap or plug all openings.
7. Remove the hose cover from the top of the jib and
remove the hydraulic hoses from the jib.
NOTE: When removing the retaining pin from the rod end of
the level cylinder, make sure the cylinder is properly
supported.
8. Remove the retaining bolt, keeper, and pin that
secures the level cylinder to the jib.
9. Remove the retaining bolt, keeper, and pin that
secures the main boom to the jib.
10. Remove the jib and platform assembly from the
boom.
11. Tag and disconnect the hydraulic lines running to
the level cylinder. Cap or plug all openings.
12. Remove the cable cover from the side of the main
boom.
13. Tag and disconnect all the hose/line couplings
found behind the cable cover. Cap or plug all open-
ings. Remove the clamp blocks securing the hoses/
lines.
14. Unbolt the power track from the boom and remove
the power track and hoses/lines from the boom.
15. Remove the cover at the rear of the boom.
16. Tag and disconnect the hydraulic lines running to
the telescope cylinder. Cap or plug all openings.
NOTE: When removing the retaining pin from the rod end of
the upper lift cylinder, make sure the cylinder is prop-
erly supported.
17. Remove the retaining bolt, keeper, and pin that
secures the upper lift cylinder rod end to the main
boom.
NOTE: When removing the retaining pin from the rod end of
the master cylinder, make sure the cylinder is prop-
erly supported.
18. Remove the retaining bolt, keeper, and pin that
secures the master cylinder rod end to the main
boom.
19. Remove the retaining bolt, keeper, and pin that
secures the main boom to the upper upright.
20. Remove the boom from the machine and place it on
suitable blocking.
Disassembly of the Main Boom
1. Loosen the wear pad retaining bolts at the rear of fly
boom section and remove the shims and wear pads
noting the location and amount of shims to aid in
reassembly.
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 the portable power source.
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. Cap or plug all open-
ings.
NOTE: When removing the retaining pin from the rod end of
the telescope cylinder, make sure the cylinder is
properly supported.
4. Remove the retaining ring and pin securing the tele-
scope cylinder rod end to the fly boom section.
5. Remove the bolts and washers securing telescope
cylinder to the rear of the base boom section.