JLG 740AJ, Service And Maintenance Manual

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SECTION 4 - BOO M & PLATFOR M
4-16 3121160
Inspection
NOTE: When inspecting pins and bearings Refer to Section 2, Pins
and Composite Bearing Repair Guidelines.
1. Inspect main boom pivot pin for wear, scoring, tapering
and ovality, or other damage. Replace pins as necessary.
2. Inspect telescope cylinder attach point for scoring,
tapering and ovality. Replace pins as necessary.
3. Inspect upper lift cylinder attach pin for wear, scoring,
tapering and ovality, or other damage. Ensure pin sur-
faces are protected prior to installation. Replace pins as
necessary.
4. Inspect inner diameter of boom pivot bearing for scor-
ing, distortion, wear, or other damage. Replace bearing
as necessary. (See Section 5, Cylinder Repair for bearing
replacement).
5. Inspect all wear pads for excessive wear, or other dam-
age. Replace pads when worn as specified in Figure 4-
12., Location and Thickness of Wear Pads.
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 bending,
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 disassem-
bly.
1. Measure inside dimensions of the base section to deter-
mine the number of shims required for proper fit.
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 TRA-
JECTORIES HAVE BEEN CLEARED OF CHAINS, TOOLS, AND OTHER OBSTRUC-
TIONS.
3. Secure the sling and lifting device at the telescope cylin-
der’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 sec-
tion. Align attachment holes in fly boom section with
hole in rod end of telescope cylinder.
5. Install telescope cylinder pin and secure with mounting
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 section.
Shim boom, if necessary, for a total of 1/32 in. (0.8 mm)
clearance.
8. Install wear pads into the forward position of the base
boom section. Shim boom, if necessary, for a total of
1/32 in. (0.8 mm) clearance.
9. Align the cylinder with the slots at aft end of base boom
section, then secure cylinder with mounting hardware.