BOOM RT770E SERVICE MANUAL
4-4
Published 11/26/2014, Control # 447-05
MAINTENANCE
Removal
NOTE: The boom assembly must be rotated 180° (upside
down) before performing any assembly or
disassembly procedures.
.
NOTE: The boom may be disassembled with the base
section left on the crane if repair of the base section
is not necessary.
NOTE: The boom weighs approximately 9125 kg
(20,150 lb). Removal of the swingaway boom
extension will simplify boom removal; therefore, the
above weight is for the boom without the
swingaway boom extension attached.
1. Extend and set the outriggers to level the crane and
ensure the boom is fully retracted and in a horizontal
position over the front of the crane.
2. If equipped, remove the swingaway boom extension
according to the removal procedures in this section;
refer to Bi-Fold Boom Extension, page 4-45.
3. Remove the hook block or headache ball and wind all
wire rope onto the hoist drum.
4. Elevate the boom slightly to allow for the withdrawal of
the lift cylinder rod end from the lift cylinder attach fitting
on the bottom of the boom.
5. Attach a lifting device to the boom that provides for equal
weight distribution.
6. Disconnect any electrical wiring from the boom.
7. Tag and disconnect the hydraulic lines to the telescope
cylinder. Cap/plug all openings.
8. Block the lift cylinder.
9. Remove the capscrews, washers, and end plate
securing the upper lift cylinder shaft to the side of the
attachment fitting on the boom.
10. Remove the upper lift cylinder shaft.
11. Activate the hydraulic system and retract the lift cylinder
rod enough to clear the attachment fitting. For removal
of the lift cylinder from the crane, refer Lift Cylinder
Removal, page 4-43.
NOTE: Shut down the crane before proceeding.
12. Take up the slack on the boom lifting device.
13. Remove the capscrew, washer and nut that passes
through the end of the weld pin that secures the boom
pivot pin in place, then remove the weld pin. Remove the
grease fitting from each end of the boom pivot shaft,
then remove the boom pivot shaft.
14. Raise the boom clear of the crane and lower to ground
level. Set cribbing under base section to level boom for
service.
CAUTION
A rollover fixture with webbing is recommended to rotate
boom and tele sections. Chains are not recommended. If
a rollover fixture is not available, rotate tele sections using
adequate support with webbing.
A secure fixture that will prevent damage to the boom is
recommended to stabilize and hold the boom from moving
during removal of any section or sections.
CAUTION
Wear gloves when handling wire rope. Moderate to minor
injury may result if using bare hands.
WARNING
Ensure the lifting device is capable of supporting the
boom assembly. Death or serious injury may result if the
lifting device cannot support the load.
WARNING
Ensure the boom lift cylinder is properly supported before
disconnecting it from the boom. Death or serious injury
may result if the lift cylinder is not supported.
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