JLG 660SJ Service Manual - Manual (Page 110)

SECTION 4 - BOOM & PLATFORM
4-8 – JLG Lift – 3120840
Disassembly of Boom Sections
1. Remove hardware securing the push bar to aft end
of the telescope cylinder, then remove pin from cyl-
inder.
2. Remove hardware securing the cover plate on the
bottom front of the base boom section.
NOTE: Do not allow wire rope to rotate. This may damage
the wire rope.
3. Clamp both threaded ends of wire rope to prevent
rotation. Note: Do not clamp on threads. Remove
jam nuts and nuts which secure the wire rope
adjustments to the bottom front of the base boom
section.
4. Remove the spring mounting plate, spring, and
proximity switch from the aft end of the base section.
5. Remove hardware securing the wire rope adjust-
ment block to aft end of the base boom section and
remove the block.
6. Remove hardware securing the telescope cylinder
to aft end of the mid boom section.
WHEN REMOVING THE TELESCOPE CYLINDER FROM THE
BOOM, IT MAY BE NECESSARY AT SOME POINT IN ORDER TO
CLEAR ASSEMBLIES MOUNTED WITHIN THE BOOM. CARE MUST
BE TAKEN TO MOVE THE CYLINDER SLOWLY FROM THE BOOM.
DAMAGE TO COMPONENTS MAY RESULT FROM FORCIBLE
IMPACT WITH THESE ASSEMBLIES.
7. Remove bolts securing wire rope attach bar to top of
fly boom section.
8. Pull the telescope cylinder and wire ropes partially
from aft end of the base boom section; secure the
cylinder with a suitable sling and lifting device at
approximately the center of gravity.
9. Carefully remove the telescope cylinder and sheave
assembly. Place telescope cylinder on a suitable
trestle.
a. Remove hardware from the wear pads; remove
wear pads from cylinder.
b. Remove hardware from the wire rope guard;
remove guard from cylinder.
c. Remove hardware from the sheave pin; remove
pin and sheave from cylinder.
10. Remove hardware which secures the wear pads to
the front of base boom section; remove wear pads
from the top, sides and bottom of the base boom
section.
11. Using an overhead crane or suitable lifting device,
remove mid and fly boom sections from base sec-
tion. Note: When removing mid and fly boom sec-
tions from base boom section, retract wire rope
must be dragged along with boom sections.
Figure 4-10. Disassembly of Proximity Switch
Assembly Figure 4-11. Disassembly of Sheave Assembly