JLG 660SJ Service Manual - Manual (Page 103)

SECTION 4 - BOOM & PLATFORM
3120840 – JLG Lift – 4-1
SECTION 4. BOOM & PLATFORM
4.1 BOOM ROPE TORQUING PROCEDURES
Torque Procedures (S Models)
1. Position boom in fully down and fully retracted posi-
tion.
2. Clamp both threaded ends of wire rope to prevent
rotation.
NOTE: Do not clamp on threads.
3. Install adjusting nuts (or remove nylon collar lock-
nuts if re-adjusting) to both retract and extend wire
ropes.
4. Torque retract adjusting nuts (platform end) to 20
Nm alternating between the two wire ropes and
keeping approximately the same amount of thread
beyond the adjusting nut.
NOTE: Do not allow wire rope to rotate. This may damage
the wire rope.
5. Repeat the torque procedure in step #4 to the
extend wire ropes (turntable end).
6. Extend the boom 0.6 to 0.9 meters using the tele-
scope function. Repeat step #4.
7. Retract the boom 0.3 to 0.6 meters using the tele-
scope function. Do not bottom out telescope cylin-
der. Repeat step #5.
8. Extend the boom approximately 0.6 to 0.9 meters
again and check torque on the retract wire ropes.
9. Retract the boom without bottoming out telescope
cylinder and check torque on the extend wire ropes.
NOTE: Step #8 and #9 may need to be repeated to equalize
the torque on all 4 wire ropes.
10. After all wire ropes have been properly torqued,
install nylon collar locknuts. Remove all clamping
devices and install all covers and guards. Check the
boom for proper function.
4.2 WEAR PADS
Tower Boom (A Models)
1. Shim up wear pads until snug to adjacent surface.
2. Replace wear pads when worn within 1.6 mm of
threaded insert.
3. When adjusting wear pads, removing or adding
shims, bolt length must also be changed.
a. When adding shims, longer bolts must be used
to ensure proper thread engagement in insert.
b. When shims are removed, shorter bolts must be
used so bolt does not protrude from insert and
come into contact with boom surface.
Main Boom
1. Shim up wear pads to within 0.8 mm tolerance
between wear pad and adjacent surface.
2. Replace wear pads when worn within 1.6 mm and
3.2 mm - B, C, D of threaded insert. See Location
and Thickness Of Wear Pads.
3. Adjusting wear pads, removing or adding shims,
bolt length must also be changed.
a. When adding shims, longer bolts must be used
to ensure proper thread engagement in insert.
b. When shims are removed, shorter bolts must be
used so bolt does not protrude from insert and
Figure 4-1. Dimensions of Boom Sections
Figure 4-2. Clamping Wire Ropes