JLG 680S Service Manual - Manual (Page 196)

SECTION 4 - BOOM & PLATFORM
4-2 – JLG Lift – 3121234
h. With powertrack support and using all applica-
ble safety precautions, remove bolts #3 and #4
securing rail to the base boom section. Remove
powertrack from boom section.
4. Remove boom assembly from machine as follows:
a. Using suitable lifting equipment, adequately
support boom assembly weight along entire
length.
HYDRAULIC LINES AND PORTS SHOULD BE CAPPED IMMEDI-
ATELY AFTER DISCONNECTING LINES TO AVOID ENTRY OF
CONTAMINANTS INTO SYSTEM.
b. Tag and disconnect hydraulic lines from tele-
scope cylinder. Use a suitable container to retain
any residual hydraulic fluid. Cap hydraulic lines
and ports.
c. Remove hardware securing the lift cylinder rod
end to the base boom section.
d. Using a suitable brass drift and hammer, remove
the lift cylinder pin from the base boom.
e. Remove hardware securing the master cylinder
rod end to the base boom section.
f. Using a suitable brass drift and hammer, remove
the master cylinder pin from the base boom.
g. Remove hardware securing the boom pivot pin
to the turntable upright.
h. Using a suitable brass drift and hammer, remove
the pivot pin from the turntable upright.
i. Using all applicable safety precautions, carefully
lift boom assembly clear of turntable and lower
to ground or suitably supported work surface.
Boom Disassembly
1. Remove hardware securing the telescope cylinder.
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 hardware securing the wire rope adjust-
ment block to aft end of the base boom section and
remove the block.
5. 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 TO TURN THE
CYLINDER SLIGHTLY IN ORDER TO CLEAR ASSEMBLIES
MOUNTED WITHIN THE BOOM. CARE MUST BE TAKEN TO MOVE
THE CYLINDER SLOWLY FROM THE BOOM. DAMAGE TO COM-
PONENTS MAY RESULT FROM FORCIBLE IMPACT WITH THESE
ASSEMBLIES.
6. Remove bolts securing wire rope attach bar to top of
fly boom section.
7. 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.
8. 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.
Figure 4-3. Location of Components - Boom Powertrack