JLG 660SJ Service Manual User Manual
Page 144
SECTION 5 - HYDRAULICS
5-12
– JLG Lift –
3120840
4.
Remove the retaining rings that retain the telescope
cylinder rod to the fly boom.
5.
Using a suitable brass drift, carefully drive telescope
cylinder rod pin #1 from the fly boom.
6.
Remove mounting hardware securing the telescope
cylinder barrel end to the base boom.
7.
Attach a suitable sling to the telescope cylinder.
Using a suitable lifting device attached to the sling,
carefully pull the cylinder partially from the aft end
boom assembly.
8.
Secure the cylinder with a suitable sling and lifting
device at the approximate center of gravity.
9.
Carefully lift the cylinder clear of the boom assembly
and lower to the ground or suitably supported work
area.
Main Boom Telescope Cylinder Installation
1.
Attach a hydraulic power supply to the telescope
cylinder ports. Using suitable supports or lifting
devices at each end of the cylinder, extend the rod
so that the cylinder pin attach holes are the same
distance apart as the boom pin attach holes.
2.
Using suitable lifting equipment, carefully lower the
cylinder to the boom assembly.
3.
Install the cylinder into the boom assembly.
4.
Remove the lifting devices from the telescope cylin-
der.
5.
Carefully install telescope cylinder rod pin #1
through the fly boom and secure it with the retaining
rings.
6.
Carefully install the telescope cylinder barrel end
support into slots in base boom and secure with
blocks and bolts. Use Loctite #242 on bolts. Shim
as necessary.
7.
Remove applicable hydraulic line and port caps and
correctly connect the hydraulic lines to the tele-
scope cylinder. Ensure all hoses are correctly
routed.
8.
Remove boom prop and overhead crane. Activate
hydraulic system.
9.
Using all applicable safety precautions, operate the
boom functions. Check for correct operation and
hydraulic leaks. Secure as necessary.
10.
Check fluid level of hydraulic tank and adjust as nec-
essary.
Main Boom Lift Cylinder Removal
1.
Place the machine on a flat and level surface. Start
the engine and place the main boom in the horizon-
tal position. Shut down engine and prop the boom.
(See Figure 5-19., Boom Positioning and Support,
Cylinder Repair (A Models).
2.
Remove the hardware retaining the cylinder rod
attach pin #2 to the boom. Using a suitable brass
drift, drive out the cylinder rod attach pin.
3.
Using auxiliary power, retract the lift cylinder rod
completely.
4.
Disconnect, cap and tag the main boom lift cylinder
hydraulic lines and ports.
5.
Remove barrel end attach pin #3 retaining hard-
ware. Using a suitable brass drift drive out the barrel
end attach pin from the upright.
6.
Remove the cylinder from the boom and place in a
suitable work area.