JLG 600A_AJ Service Manual - Manual (Page 180)

SECTION 4 - BOOM & PLATFORM
4-4 – JLG Lift – 3121201
f. Remove bolt #1 securing the push tube on the
fly boom section.
g. Remove bolt #2 securing the push tube on the
mid boom section.
h. With powertrack support and using all applica-
ble safety precautions, remove bolts #3, #4 and
#5 securing rail to the base boom section.
Remove powertrack from boom section.
4. Remove boom assembly from machine as follows:
a. Using a suitable lifting equipment, adequately
support boom assembly weight along entire
length.
HYDRAULIC LINES AND PORTS SHOULD BE CAPPED IMMEDI-
ATELY AFTER DISCONNECTING LINES TO AVOID ENTRY OF CON-
TAMINANTS INTO SYSTEM.
b. Tag and disconnect hydraulic lines from tele-
scope cylinder. Use suitable container to retain
any residual hydraulic fluid. Cap hydraulic lines
and ports.
c. Remove hardware securing the lift cylinder rod
end to the base boom section.
d. Using a suitable brass drift and hammer, remove
the lift cylinder pin from base boom.
e. Remove hardware securing the master cylinder
rod end to the base boom section.
f. Using a suitable brass drift and hammer, remove
the master cylinder pin from base boom.
g. Remove hardware securing the boom pivot pin
to the turntable upright.
h. Using a suitable brass drift and hammer, remove
the pivot pin from turntable upright.
i. Using all applicable safety precautions, carefully
lift boom assembly clear of turntable and lower
to ground or suitably supported work surface.
Disassembly of Boom Sections
1. Remove hardware securing telescope cylinder to aft
end of the base boom section.
2. Remove hardware which secures the wear pads to
the base boom section; remove the wear pads from
the top, sides and bottom of the base boom section.
3. Using overhead crane or suitable lifting device,
remove fly boom assembly from base section.
4. Remove hardware from the telescope cylinder pin.
Using a suitable brass drift and hammer remove the
cylinder pin from fly boom section.
5. Pull the telescope cylinder partially from aft end of
the fly boom section; secure the cylinder with a suit-
able sling and lifting device at approximately the
center of gravity.
6. Carefully remove the telescope cylinder and place
telescope cylinder on a suitable trestle.
7. Remove hardware which secures the wear pads to
the aft end of fly boom section; remove the wear
pads from the top, sides and bottom of the fly boom
section.
Inspection
NOTE: When inspecting pins and bearings refer to Section 2
- General.
1. Inspect boom pivot pin for wear, scoring, tapering
and ovality, or other damage. Replace pins as nec-
essary.
2. Inspect telescope cylinder attach point for scoring,
tapering and ovality. Replace pins as necessary.
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.
Figure 4-4. Location of Components - Boom
Powertrack