JLG 740AJ Service Manual - Manual (Page 298)

SECTION 5 - HYDRAULICS
5-12 – JLG Lift – 3121160
5. Remove overhead crane and sling. Activate hydrau-
lic system.
6. Using all applicable safety precautions, operate the
boom functions. Check for correct operation and
hydraulic leaks. Secure as necessary.
7. Check fluid level of hydraulic tank and adjust as nec-
essary.
Upright Level Cylinder Removal
1. With the aid of an assistant, manually override the
Plunger Valve with a pry bar, and from Ground Con-
trol, using auxiliary power, extend the tower tele-
scope out to gain access to leveling cylinder rod
end pin.
NOTE: Attach the sling approximately 24" toward the
upright, from the boom rest pad on the turntable for
balancing the main boom and upright.
2. Tag, disconnect electrical and hydraulic lines and
cap the hydraulic lines of the power track and main
boom.
3. Remove mounting hardware of master cylinder rod
end pin.
4. Using a suitable drift, remove the master cylinder
rod end pin.
5. Remove mounting hardware of main lift cylinder rod
end pin.
6. While supporting the main boom with adequate
crane and sling, use a suitable drift to remove the
main lift cylinder rod end pin.
7. Remove the mounting hardware of the main boom
pivot pin.
8. Using a suitable drift, drive the attach pin through
the mounting holes of the upright and the main
boom.
THE UTMOST SAFETY PRECAUTIONS ARE TO BE TAKEN AT THIS
POINT, AS THIS WILL ALLOW THE MAIN BOOM TO SEPARATE
FROM THE UPRIGHT.
9. Slide the disconnected main boom toward the plat-
form and allow to rest on tower boom and turntable
rest.
10. Using a adequate lifting device, attach and support
the upright.
11. Remove mounting hardware securing the upright
level cylinder barrel end pin to the upright.
12. Using a suitable drift, drive the upright level cylinder
barrel end pin through the mounting holes of the
upright.
13. Attach a suitable lifting device to the upright level
cylinder.
14. Using a suitable drift, remove the upright level cylin-
der rod end pin from the tower fly boom.
15. Carefully remove the upright level cylinder from the
tower fly boom. Place in a suitable work area.
Upright Level Cylinder Installation
1. Place the leveling cylinder in position in the tower
boom, then align holes in tower boom and leveling
cylinder. Install leveling cylinder rod end attach pin,
using a suitable rubber mallet.
2. Secure pin to tower boom with mounting hardware.
3. Remove cylinder port plugs and hydraulic line caps
and correctly attach lines to cylinder ports.
4. Using all applicable safety precautions, operate the
overhead crane to move upright assembly into
proper position.
5. Align holes in upright and barrel end of level cylinder
and install level barrel end pin, using a suitable rub-
ber mallet. Secure pin with mounting hardware.
THE UTMOST SAFETY PRECAUTIONS ARE TO BE TAKEN AT THIS
POINT, LIFTING THE MAIN BOOM TO ATTACH TO THE PIVOT
POINT OF THE UPRIGHT
6. Using all applicable safety precautions, operate the
crane to lift main boom assembly into proper posi-
tion.
7. Align holes in upright and main boom and install
main boom pivot pin, using a suitable rubber mallet.
Secure pin with mounting hardware.
8. Align the mounting holes of the main lift cylinder and
the main boom. Install the main lift rod end pin,
using a suitable rubber mallet. Secure pin with
mounting hardware.
9. Align the mounting holes of the master cylinder and
the main boom. Install the master cylinder pin, using
a suitable rubber mallet. Secure pin with mounting
hardware.
10. Remove hydraulic line caps and correctly attach all
tagged hydraulic and electrical lines.
11. Remove overhead crane from upper boom. Activate
hydraulic system.