Part No. 102521
S-40 • S-45
4 - 21
October 2013
Section 4 • Repair Procedures
4-3
Boom Lift Cylinder
The boom lift cylinder raises and lowers the boom.
The boom lift cylinder is equipped with
counterbalance valves to prevent movement in the
event of a hydraulic line failure.
How to Remove the Boom
Lift Cylinder
Bodily injury hazard. This
procedure requires specific repair
skills, lifting equipment and a
suitable workshop. Attempting this
procedure without these skills and
tools could result in death or
serious injury and significant
component damage. Dealer
service is strongly recommended.
Note: When removing a hose assembly or fitting,
the O-ring on the fitting and/or hose end must be
replaced and then torqued to specification during
installation. Refer to Section 2,
Hydraulic Hose and
Fitting Torque Specifications.
1 Raise the boom to a horizontal position.
2 Place support blocks across the turntable under
the boom lift cylinder.
3 Attach a 5 ton / 5000 kg overhead crane to the
boom at the platform end for support. Do not lift
the boom.
4 Support and secure both ends of the boom lift
cylinder to a second overhead crane or similar
lifting device.
5 Tag, disconnect and plug the boom lift cylinder
hydraulic hoses. Cap the fittings on the cylinder.
Bodily injury hazard. Spraying
hydraulic oil can penetrate and
burn skin. Loosen hydraulic
connections very slowly to allow
the oil pressure to dissipate
gradually. Do not allow oil to
squirt or spray.
6 Remove the pin retaining fastener from the
boom lift cylinder rod-end pivot pin. Use a soft
metal drift to remove the pin. Lower the lift
cylinder onto the blocks. Protect the cylinder
rod from damage.
Crushing hazard. The lift cylinder
could become unbalanced and fall
if it is not properly supported.
7 Remove the four mounting fasteners from the
lift cylinder barrel-end pivot pin mounting plate.
8 With the lift cylinder being supported by the
overhead crane, pull the cylinder toward the
platform to remove it from the machine.
Crushing hazard. The lift cylinder
could become unbalanced and fall
if it is not properly supported.
Component damage hazard. The
cables and hydraulic hoses can be
damaged if the lift cylinder is
pulled across them.
9 Using auxiliary power, activate the boom down
function so the cylinder will retract. Retract the
cylinder just enough until the rod end of the
cylinder will clear the mounting bracket on the
boom. Turn the machine off.
BOOM COMPONENTS
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