JLG 680S, Service And Maintenance Manual

Page: 291 / 530

SECTION 4 - BOOM & PLATFORM
3121234 4-27
Inspection
NOTE: When inspecting pins and bearings Refer to the guidelines
established in Section 2 - General.
1. Inspect all sheaves (extend and retract wire ropes and
telescope cylinder) for excessive groove wear, burrs or
other damage. Replace sheaves as necessary.
NOTE: To check the size, contour and amount of wear, a groove
gauge is used. Replace the sheave if worn as shown in the
following drawing.
2. Inspect extend and retract wire rope sheave bearings for
wear, scoring, or other damage, and for ovality.
3. Inspect extend wire rope and retract wire rope sheave
pins for scoring, tapering and ovality. Replace pins as
necessary.
4. Inspect telescope cylinder sheave pin for scoring, taper-
ing and ovality. Replace pins as necessary.
5. Inspect boom pivot pin for wear, scoring, tapering and
ovality, or other damage. Replace pins as necessary.
6. Inspect telescope cylinder attach point for scoring,
tapering and ovality. Replace pins as necessary.
7. 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.
8. Inspect inner diameter of boom pivot bushing for scor-
ing, distortion, wear, or other damage. Replace bearing
as necessary.
9. Inspect all wear pads for excessive wear or other dam-
age. Replace pads when worn to within 1/8 in. (3.2 mm)
of threaded insert.
10. Inspect extend and retract wire rope attach point com-
ponents for cracks, stretching, distortion, or other dam-
age. Replace components as necessary.
11. Inspect all threaded components for damage such as
stretching, thread deformation, or twisting. Replace as
necessary.
12. 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 and mid sections
to determine the number of shims required for proper
lift.
2. Measure inside dimensions of the mid section to deter-
mine the number of shims required for proper lift.
3. Install side, top and bottom wear pads to the rear end of
fly section; shim evenly to the measurements of the
inside of mid section.
Figure 4-13. Dimension of Sheaves When New