JLG 680S Service Manual - Manual (Page 203)

SECTION 4 - BOOM & PLATFORM
3121234 – JLG Lift – 4-9
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 neces-
sary.
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 bear-
ings 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,
tapering and ovality. Replace pins as necessary.
5. Inspect boom pivot pin for wear, scoring, tapering
and ovality, or other damage. Replace pins as nec-
essary.
6. Inspect telescope cylinder attach point for scoring,
tapering and ovality. Replace pins as necessary.
7. 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.
8. Inspect inner diameter of boom pivot bushing for
scoring, distortion, wear, or other damage. Replace
bearing as necessary.
9. 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.
10. Inspect extend and retract wire rope attach point
components for cracks, stretching, distortion, or
other damage. 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 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 and mid
sections to determine the number of shims required
for proper lift.
2. Measure inside dimensions of the mid section to
determine the number of shims required for proper
lift.
3. Install side, top and bottom wear pads to the aft end
of fly section; shim evenly to the measurements of
the inside of mid section.
Figure 4-9. Dimension of Sheaves When New