JLG 660AJ Service Manual - Manual (Page 151)

SECTION 4 - BOOM & PLATFORM
3121616 – JLG Lift – 4-3
Remove Main Boom
1. Support boom assembly weight along entire length
using suitable lifting equipment.
CAP HYDRAULIC LINES AND PORTS IMMEDIATELY AFTER DISCONNECTING
LINES TO PREVENT SYSTEM CONTAMINATION.
2. Tag and disconnect hydraulic lines from telescope cylin-
der. Use suitable container to retain any residual hydrau-
lic fluid. Cap hydraulic lines and ports.
3. Remove hardware securing lift cylinder rod end to base
boom section.
4. Remove lift cylinder pin from base boom using a suit-
able brass drift and hammer.
5. Remove hardware securing master cylinder rod end to
base boom section.
6. Remove master cylinder pin from base boom using a
suitable brass drift and hammer.
7. Remove hardware securing boom pivot pin to turntable
upright.
8. Using a suitable brass drift and hammer, remove pivot
pin from turntable upright.
9. Using all applicable safety precautions, carefully lift
boom assembly clear of turntable. Lower to ground or
suitably supported work surface.
DISASSEMBLE
1. Remove hardware securing telescope cylinder to aft end
of main boom section.
2. Remove hardware and wear pads from top, sides, and
bottom of main boom section.
3. Remove fly boom assembly from main boom using
overhead crane or suitable lifting device.
4. Remove hardware from telescope cylinder pin. Remove
cylinder pin from fly boom section using a suitable brass
drift and hammer.
5. Pull telescope cylinder partially from aft end of fly boom.
Secure cylinder with a suitable sling and lifting device at
center of gravity.
6. Carefully remove telescope cylinder and place on a suit-
able trestle.
7. Remove hardware and wear pads from top, sides, and
bottom of fly boom section.
INSPECTION
NOTE: Replace worn or damage components as needed.
1. Inspect boom pivot pin for wear, scoring, tapering and
ovality, or other damage.
2. Inspect telescope cylinder attach point for scoring,
tapering and ovality.
3. Inspect upper lift cylinder attach pin for wear, scoring,
tapering and ovality, or other damage. Protect pin sur-
faces before installation.
4. Inspect inner diameter of boom pivot bearing for scor-
ing, distortion, wear, or other damage.
5. Inspect wear pads for excessive wear or other damage.
Replace pads when worn to within 1/8 inch (3.2 mm) of
threaded insert or damaged.
6. Inspect threaded components for stretching, thread
deformation, twisting, or other damage.
7. Inspect structural units of boom assembly for bending,
cracking, separation of welds, or other damage.
ASSEMBLY
NOTE: Install same number and thickness of shims removed.
1. Measure inside dimensions of base section to determine
number of shims required for proper lift.
2. Install side, top, and bottom wear pads to aft end of fly
section. Shim evenly to inside measurements of base
boom section.
ENSURE BOOM SLIDING AREAS ARE CLEAR OF CHAINS, TOOLS, AND OTHER
OBJECTS WHEN ASSEMBLING BOOM SECTIONS.
3. Secure sling and lifting device at telescope cylinder cen-
ter of gravity. Lift cylinder to aft end of fly boom section.
4. Slide telescope cylinder in 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. Secure with mounting
hardware.
6. Secure sling and lifting device at fly boom center of
gravity.
7. Slide fly boom assembly in base boom section. Check for
1/16 inch (0.062) clearance. Shim if needed.
8. Install wear pads in forward position of base boom sec-
tion. Check for 2/10 inch (0.20) clearance. Shim if
needed.
9. Align cylinder with slots at aft end of base boom section.
Secure cylinder with mounting hardware.