JLG 600SC_660SJC Service Manual - Manual (Page 95)

SECTION 5 - HYDRAULICS
3120898 – JLG Lift – 5-9
5.5 CYLINDER REMOVAL AND
INSTALLATION
Main Boom Telescope Cylinder Removal
1. Place machine on a flat and level surface, with main
boom in the horizontal position.
2. Shut down engine. Support main boom basket end
with a prop. (See Figure 5-14., Boom Positioning
and Support, Cylinder Repair).
HYDRAULIC LINES AND PORTS SHOULD BE CAPPED IMMEDI-
ATELY AFTER DISCONNECTING LINES TO AVOID THE ENTRY OF
CONTAMINANTS INTO THE SYSTEM.
3. Tag and disconnect hydraulic lines to telescope cyl-
inder. Use a suitable container to retain any residual
hydraulic fluid. Cap hydraulic lines and ports.
4. Remove the hardware securing cover plate on bot-
tom of the base boom section and remove cover.
NOTE: Do not allow cable to rotate. This may damage the
cable.
5. Clamp both threaded ends of cable to prevent rota-
tion. Note: Do not clamp on threads. Remove jam
nuts and loosen adjustment nuts so there is slack in
the cables. Remove the hardware securing push bar
to turntable and telescope cylinder.
6. Using a suitable brass drift, carefully drive the push
bar pins from the telescope cylinder rod and turnta-
ble.
7. Remove hardware securing cable adjustment block
to aft end of the base boom section and remove
block.
8. Remove hardware securing telescope cylinder to aft
end of the mid boom section.
WHEN REMOVING THE TELESCOPE CYLINDER FROM THE
BOOM, IT MAY BE NECESSARY AT SOME POINT TO TURN THE
CYLINDER SLIGHTLY IN ORD ER TO CLEAR ASSEMBLIES
MOUNTED WITHIN THE BOOM. CARE MUST BE TAKEN TO MOVE
THE CYLINDER SLOWLY INTO POSITION: DAMAGE TO COMPO-
NENTS MAY RESULT FROM FORCIBLE IMPACT WITH THESE
ASSEMBLIES.
9. Remove bolts securing cable attach bar to top of fly
boom section.
10. Pull the telescope cylinder and cables partially from
aft end of the base boom section; secure the cylin-
der with a suitable sling and lifting device at approxi-
mately the center of gravity.
11. Carefully remove the telescope cylinder and sheave
assembly. Place telescope cylinder on a suitable
trestle.
Main Boom Telescope Cylinder Installation
1. Route extend cables around extend sheave and
secure cables to the telescope cylinder.
2. Install extend cables mounting blocks to threaded
ends of cables. Loosely install nuts and jam nuts
onto the threaded end of cables.
NOTE: When installing cables care must be taken not to
twist or cross the cables.
3. Secure the sling and lifting device at the telescope
cylinder’s approximate center of gravity, and lift the
cylinder to the aft end of the boom assembly.
Figure 5-14. Boom Positioning and Support, Cylinder Repair