JLG E300 Service Manual - Manual (Page 87)

SECTION 4 - BOOM & PLATFORM
3120772 – JLG Lift – 4-1
SECTION 4. BOOM & PLATFORM
4.1 BOOM MAINTENANCE
IF PERFORMING MAINTENANCE ON THE BOOM, DO NOT USE A
LIFTING DEVICE TO LIFT THE BOOMS UNLESSTHE HOLDING
VALVES HAVE BEEN REMOVED FIRST. FAILURE TO DO SO WILL
RESULT IN SEVERE DAMAGE TO THE BOOM.
Removal of the Boom Assembly
1. Remove the platform and platform support as fol-
lows:
a. Disconnect electrical cable from control con-
sole.
b. Tag and disconnect the hydraulic lines running
to the rotate cylinders. Cap the hydraulic lines
and ports.
c. Using an overhead crane or suitable lifting
device, use nylon support straps to support the
platform/support, and jib if applicable.
NOTE: When removing the retaining pin from the rod end of
the level cylinder, make sure the cylinder is properly
supported.
d. Remove bolts and keeper pins that secures the
retaining pins. Using a suitable brass drift and
hammer, remove the retaining pins from the plat-
form support.
2. Remove the boom from the turntable as follows:
a. Disconnect wiring harness from ground control
harness connector.
HYDRAULIC LINES AND PORTS SHOULD BE CAPPED IMMEDI-
ATELY AFTER DISCONNECTING LINES TO AVOID ENTRY OF CON-
TAMINANTS INTO SYSTEM.
b. Tag and disconnect hydraulic lines from boom
to control valve. Use a suitable container to
retain any residual hydraulic fluid. Cap all
hydraulic lines and ports.
c. Using a suitable lifting equipment, adequately
support boom weight along entire length.
d. Remove the bolts and keeper pins securing the
lift cylinder pivot pin. Using a suitable brass drift
and hammer, remove the pivot pin from the
lower boom.
e. Remove hardware securing the level link pivot
pin. Using a suitable brass drift and hammer,
remove the pin from the level link and turntable.
f. Remove hardware securing the lower boom
pivot pin. Using a suitable brass drift and ham-
mer, remove pin from the turntable.
g. Using all applicable safety precautions, carefully
lift boom assembly clear of turntable and lower
to ground or suitable supported work surface.
Disassembly of the Main Boom
1. Loosen bolts on aft end of fly boom wear pads and
remove shims.
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 POWER-
TRACK.