JLG G6-42A Operator Manual - Manual (Page 55)

Form No. 20036 • G6-42A Owner/Operator Manual
17.4
Checking & Adjusting Boom
Boom Bearing Pads
Boom bearing pads are to be adjusted for all boom sections. This
should be done at boom assembly, however, some adjustments may
be required after assembly.
• Add shims as required so that front and sides of boom
have no more than 1.5mm (.06 inch) clearance.
• Add shims as required so that rear of boom has no more
than 3.04mm (.12 inch) total clearance.
• Number of shims at each pad may vary, however shims at
bottom front pads must not vary more than one shim
between sides.
• Pads must not directly contact shims, thus a spacer must
be inserted between pad and shims.
• Use Loctite 242 (Gradall P/N 1440-3364) on screws when
adding or removing shims.
Boom Chain
Check boom chain adjustment. With boom horizontal, extend boom
1.2m to 1.5m (4 to 5 feet), then fully retract boom. Measure gap
between all bevel washers on extend chain rod, and add them
together. If total of all gaps exceeds 3.04mm (.12 inch), boom chain
will need to be adjusted. Adjust as follows:
A. Loosen lock nut on extend chain rod.
B. Tighten adjusting nut on extend chain rod until all washers
are just flat (no gap between any washers).
C. Torque lock nut to 100 ft.-lb.
After adjusting, check that boom sections and / or access holes in
side of boom are aligned. If they are not, retract chain will require
adjustment as follows:
A. Fully retract boom.
B. Measure distance between 2 nd and 3 rd boom sections.
Determine amount of misalignment.
C. Loosen extend chain lock nut and adjusting nut as far as
possible.
D. Loosen retract chain lock nut and adjusting nut.
E. Tighten retract chain adjusting nut until proper distance
between 2 nd and 3 rd boom sections and proper access hole
alignment is obtained.
F. Torque lock nut to 100 ft.-lb.
G. Adjust extend chain per instructions above.
For more detailed information, including boom chain checks and adjustments,
see the appropriate Service Manual.
BOOM