JLG 4017 Service Manual - Manual (Page 28)

Boom
3.4 4017
9. Support the extend/retract cylinder and remove the
clip and pin from rod end of extend/retract cylinder.
Remove the clip and pin from barrel end of extend/
retract cylinder and remove the extend/retract
cylinder.
10. Disconnect the boom angle indicator rod from switch
at the inside left rear corner of the main boom
section and frame. Refer to Section 9.11.9, “Boom
Angle Sensor,” for adjustment information.
11. Support the front of the boom by placing a sling
behind the boom head. Support the lift/lower cylinder
and remove the lock bolt and then the rod end pin.
Lower the lift/lower cylinder onto the frame rails.
12. Remove the lock bolt and pin from compensation
cylinder on each side of first boom section. Remove
the lock bolt and pivot pin from rear of first boom
section.
13. Lower the boom to a level position and place a
suitable support under the boom head. Reposition
the slings to each end of the boom.
14. Lift the complete boom (1) off machine and set on
level ground or supports being careful not to damage
the tubes on the left side of boom.
Note: In the following sections the individual boom
sections are removed as follows:
1. Remove second, third and fourth boom sections as
one unit from the first boom section.
2. Remove third and fourth boom sections as one unit
from the second boom section.
3. Remove fourth boom section from the third boom
section.
4. Remove hose carrier from fourth boom section.
3.3.2 Second, Third & Fourth Boom Section
Removal
1. Set the complete boom on level ground and by
repositioning the slings turn boom over on to the top
side. Set the complete boom (2) on suitable stands
to begin tear down.
Note: With the complete boom setting upside down, the
removal and replacing of each boom section, tilt cylinder,
hoses, extend and retract chains and hose carrier are
made much easier.
2. At the boom head attach a sling through rod end of
tilt cylinder. Remove both hoses from tilt cylinder.
Plug the hose ends and cap the tilt cylinder fittings to
prevent dirt and debris from entering the hydraulic
system. Remove the clip from barrel end of tilt
cylinder pin. Remove the tilt cylinder pin and lift the
tilt cylinder out of the boomhead.
MZ0820
1
(before being turned over)
MZ0740
2
(after being turned over)
MZ0750
3