JLG 660AJ Service Manual - Manual (Page 186)

SECTION 5 - HYDRAULICS
5-6 – JLG Lift – 3121616
Main Boom Telescope Cylinder Removal
1. Place machine on flat and level surface with main boom
horizontal. Extend telescope for access to cylinder rod
pin (1).
2. Shut down engine. Support main boom basket end with
a prop (2). See Figure 5-1., Boom Positioning and Sup-
port, Cylinder Repair.
CAP HYDRAULIC LINES AND PORTS IMMEDIATELY AFTER DISCONNECTING
LINES TO PREVENT SYSTEM CONTAMINATION.
3. Tag and disconnect hydraulic lines to telescope cylinder
(1). Use suitable container to retain any residual hydrau-
lic fluid. Cap hydraulic lines and ports.
4. Remove bolt and keeper pin from cylinder rod pin (3).
5. Carefully drive telescope cylinder rod pin from fly boom
using a suitable brass drift.
6. Remove four bolts (4), two blocks (5), and shims (6) from
telescope cylinder barrel end support.
7. Attach a suitable sling to telescope cylinder. Attach suit-
able lifting device to sling and pull cylinder partially
from boom assembly.
8. Secure cylinder with a suitable sling and lifting device at
approximate center of gravity.
9. Lift cylinder clear of boom assembly. Lower to ground or
suitably supported work area.
Main Boom Telescope Cylinder Installation
1. Attach hydraulic power supply to telescope cylinder
ports. Using suitable supports or lifting devices at each
end of cylinder, extend rod so cylinder pin holes are
same distance apart as boom pin attach holes.
2. Using suitable lifting equipment, carefully lower cylin-
der to boom assembly.
3. Install cylinder in boom assembly.
4. Remove lifting devices from telescope cylinder (1).
5. Install telescope cylinder rod pin (3) in fly boom. Install
keeper pin and bolt.
6. Install telescope cylinder barrel end support in slots in
base boom. Apply JLG Thread Locking Compound P/N
0100011 to bolts (4) and install with shims (6) and blocks
(4).
7. Remove hydraulic line and port caps. Correctly route
and connect hydraulic lines as tagged to the telescope
cylinder.
8. Remove boom prop and overhead crane. Activate
hydraulic system.
9. Operate boom functions following all applicable safety
10. precautions. Check for correct operation and hydraulic
leaks. Secure as necessary.
11. Check fluid level of hydraulic tank. Adjust as needed.
Figure 5-3. Telescope and Lift Cylinder Installation
7
3
1
4
5
6
2
8
9