JLG 660SJ ANSI Service Manual - Manual (Page 152)

SECTION 4 - BOOM & PLATFORM
4-16 – JLG Lift – 3120718
3. Inspect upper lift cylinder attach pin for wear, scor-
ing, tapering and ovality, or other damage. Ensure
pin surfaces are protected prior to installation.
Replace pins as necessary.
4. Inspect inner diameter of boom pivot bearing for
scoring, distortion, wear, or other damage. Replace
bearing as necessary.
5. Inspect all wear pads for excessive wear, or other
damage. Replace pads when worn to within 1/8 inch
(3.2 mm) of threaded insert.
6. Inspect all threaded components for damage such
as stretching, thread deformation, or twisting.
Replace as necessary.
7. Inspect structural units of boom assembly for bend-
ing, cracking, separation of welds, or other damage.
Replace boom sections as necessary.
Assembly
NOTE: When installing fly section wear pads, install same
number and thickness of shims as were removed
during disassembly.
1. Measure inside dimensions of the base section to
determine the number of shims required for proper
lift.
2. Install side, top and bottom wear pads to the aft end
of fly section; shim evenly to the measurements of
the inside of base boom section.
WHEN ASSEMBLING BOOM SECTIONS, ENSURE THAT THE
BOOM SLIDING TRAJECTORIES HAVE BEEN CLEARED OF
CHAINS, TOOLS, AND OTHER OBSTRUCTIONS.
3. Secure the sling and lifting device at the telescope
cylinder’s approximate center of gravity, and lift the
cylinder to the aft end of the fly boom section.
4. Slide telescope cylinder into the aft end of fly boom
section. Align attachment holes in fly boom section
with hole in rod end of telescope cylinder.
5. Install telescope cylinder pin and secure with mount-
ing hardware.
6. Secure the sling and lifting device at the fly boom
assembly approximate center of gravity.
7. Slide fly boom assembly into the base boom sec-
tion. Shim boom, if necessary, for a total of 1/16 inch
(0.062) clearance.
8. Install wear pads into the forward position of the
base boom section. Shim boom, if necessary, for a
total of 2/10 inch (0.20) clearance.
9. Align the cylinder with the slots at aft end of base
boom section, then secure cylinder with mounting
hardware.
Installation
1. Using a suitable lifting device, position boom
assembly on turntable so that the pivot holes in both
boom and turntable are aligned.
2. Install boom pivot pin, ensuring that location of hole
in pin is aligned with attach point on turntable.
3. If necessary, gently tap pin into position with soft
headed mallet. Secure pin mounting hardware.
4. Connect all wiring connectors to the correct connec-
tors.
5. Connect all hydraulic lines running along side of
boom assembly.
6. Using all applicable safety precautions, operate lift-
ing device in order to position boom lift cylinder so
that holes in the cylinder rod end and boom struc-
ture are aligned. Insert the lift cylinder pin, ensuring
that location of hole in pin is aligned with attach
point on boom.
7. Align holes in boom structure with hole in master
cylinder. Insert the master cylinder pin, ensuring that
location of hole in pin is aligned with attach point on
boom.
8. Using all applicable safety precautions, operate
machine systems and raise and extend boom fully,
noting the performance of the extension cycle.
9. Retract and lower boom, noting the performance of
the retraction cycle.