JLG 800A_AJ Service Manual - Manual (Page 308)

SECTION 5 - HYDRAULICS
5-26 – JLG Lift – 31208858
Upper Boom Lift Cylinder Installation
1. Using suitable lifting device and sling, lift the upper
boom to allow enough space to lower the upper lift
cylinder to align with pin mounting holes of the
tower fly boom and barrel end of upper lift cylinder.
2. Using a suitable drift, drive barrel end attach pin
through the mounting holes in the lift cylinder and
the tower fly boom. Secure in place with the pin and
retaining hardware.
3. Remove cylinder port plugs and hydraulic line caps
and correctly attach lines to cylinder ports.
4. Using auxiliary power extend the cylinder rod until
the attach pin hole aligns with those in the upper
boom. Using a suitable drift drive cylinder rod attach
pin through the aligned holes, taking care to align
the grooved pin holes. Secure the pin in place with
attaching hardware.
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 upper boom and upright.
2. Tag, disconnect electrical and hydraulic lines and
cap the hydraulic lines of the power track and upper
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 upper lift cylinder
rod end pin.
6. While supporting the upper boom with adequate
crane and sling, use a suitable drift to remove the
upper lift cylinder rod end pin.
7. Remove the mounting hardware of the upper boom
pivot pin.
8. Using a suitable drift, drive the attach pin through
the mounting holes of the upright and the upper
boom.
THE UTMOST SAFETY PRECAUTIONS ARE TO BE TAKEN AT THIS
POINT, AS THIS WILL ALLOW THE UPPER BOOM TO SEPARATE
FROM THE UPRIGHT.
9. Slide the disconnected upper 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.