JLG 120-SXJ Service Manual - Manual (Page 56)

SECTION 4 - BOOM & PLATFORM
4-8 – JLG Lift – 3121810
5. Using all applicable safety precautions, operate lift-
ing equipment in order to position boom lift cylinder
so that holes in cylinder rod end and boom structure
are aligned. Insert lift cylinder pin.
6. If necessary, gently tap pin into position with a soft
headed mallet, ensuring that pin plate holes are
aligned with attach holes in boom structure. Install
pin attaching bolts, washers and lockwashers.
7. Shut down machine systems.
8. Connect hydraulic lines running along side of boom.
9. Install boom length/angle sensor box. Adjust boom
length/angle sensor box in accordance with proce-
dures in this manual.
10. Using all applicable safety precautions, operate
machine systems and raise and extend boom fully,
noting the performance of the extension cycle. If
chattering is apparent, extend chain system requires
adjustment.
11. Retract and lower boom, noting performance of
retraction cycle. If chattering is apparent, retract
chain system requires adjustment.
12. Shut down machine systems.
13. Adjust extend and retract chain systems as required
and secure adjustment locknuts.
14. As necessary, lubricate all points requiring lubrica-
tion.
4.2 BOOM CHAINS
Adjusting Procedures
ENSURE MACHINE IS ON A FIRM AND LEVEL SURFACE.
1. Position boom fully retracted at +5 degrees horizon-
tal, no load in platform.
2. Torque outer mid section extend chain adjuster to 80
Nm (59 ft. lb.).
3. Torque outer mid section retract chain adjuster to 80
Nm (59 ft. lb.).
4. Torque fly section extend chain adjuster to 80 Nm
(59 ft. lb.).
5. Torque fly section retract chain adjuster to 80 Nm
(59 ft. lb.).
6. Cycle boom (extend at least 2 meters [6 feet], then
retract fully).
7. Recheck outer mid section extend chain.
8. Recheck outer mid section retract chain.
9. Recheck fly section extend chain.
10. Recheck fly section retract chain.
11. Repeat steps (2) thru (10) if necessary.
12. Check for proper operation of boom.
JLG Industries, Inc. requires a complete boom disassem-
bly, per the instructions outlined in Section 4.1, Boom
Maintenance, every two years. All boom chains and
related components (i.e., sheaves, pins, sprockets, wear
pads, etc.) must also be inspected and replaced, as nec-
essary, during this disassembly.
An immediate disassembly of the boom assembly and
inspection of the boom chains and related components is
required if any of the following conditions occur:
1. After machine is exposed to hostile environments or
conditions (i.e., extreme cold, dust, sand, blasting
grit, salt, chemicals, etc.) which could adversely
affect boom operation.
2. Erratic boom operation or unusual noise exists.
Refer to troubleshooting tables in Section 3.
3. Chain adjustment is required more often than speci-
fied in this Section or links need to be removed
(chain shortened) to make adjustment.
4. Machine is idle for an extended period (6 months or
longer).
5. Boom is overloaded or has sustained a shock load.
FAILURE TO DISASSEMBLE THE BOOM ASSEMBLY AND PROP-
ERLY INSPECT AND/OR REPLACE THE BOOM CHAINS AND
RELATED COMPONENTS (I.E., SHEAVES, PINS, SPROCKETS,
WEAR PADS, ETC.) COULD RESULT IN THE DAMAGE AND/OR
BREAKAGE OF THE BOOM CHAINS AND/OR RELATED COMPO-
NENTS. DAMAGE AND/OR BREAKAGE OF THESE ITEMS COULD
RESULT IN UNCONTROLLED EXTENSION OR RETRACTION OF
THE BOOM ASSEMBLY AND COULD CAUSE SERIOUS INJURY OR
DEATH TO PERSONNEL OPERATING THE JLG BOOM LIFT.