JLG 120HX ANSI Service Manual - Manual (Page 32)

SECTION 2 - PROCEDURES
2-12 – JLG Lift – 3120686
7. Install the two (2) extension chain adjusting nuts at
the aft end of the base boom.
8. Install the rod support bracket at the aft end of the
base boom.
9. Remove the sling attached to the telescope cylinder
rod.
10. Pull boom sections back into the fully retracted posi-
tion.
11. Using a suitable brass drift, if necessary, install the
half pins attaching the telescope cylinder to the
inner mid boom section.
12. Install setscrews that attach the telescope cylinder
attach pins to each side of the telescope cylinder
trunnions.
13. Install the telescope cylinder trunnion attach pin
cover to each side of the base boom.
14. Carefully install the telescope cylinder rod attach pin
into the base boom.
15. Install the two (2) cotter pins that retain the tele-
scope rod attach pin to the base boom.
16. Remove applicable hydraulic line and port caps and
correctly connect the hydraulic lines to the tele-
scope cylinder. Ensure that all hoses are correctly
routed.
17. Cycle telescope function several times to dissipate
any air from cylinder and lines. Properly torque
boom chains to 59 ft. lb. (80 Nm).
18. Install boom length/angle indicator on boom assem-
bly.
NOTE: Boom length/angle indicator will need to be adjusted
as per the procedure listed in paragraph 2-24 of this
manual.
19. Using all applicable safety precautions, operate the
boom functions. Check for correct operation and
hydraulic leaks. Secure as necessary.
20. Install boom end cover.
21. Retract boom fully and place in stowed position.
Lift Cylinder Removal
1. Place the machine on a flat and level surface. Start
the engine and place the boom in a horizontal posi-
tion. Shut down the engine and attach a suitable
support device to the boom.
2. Tag, disconnect and cap the lift cylinder hydraulic
lines and ports.
3. Remove the bolt, flatwasher and lockwasher secur-
ing the cylinder rod attach pin retaining plate to the
boom.
4. Remove the two bolts and two lockwashers securing
the pin retaining plate to the pin. Using a suitable
brass drift drive out the cylinder rod attach pin.
5. Using auxiliary power, retract the lift cylinder rod
completely.
6. Remove the barrel end attach pin retaining plate and
hardware. Using a suitable brass drift drive out the
barrel end attach pin from the upright.
7. Remove the cylinder from the boom and place in a
suitable work area.
Lift Cylinder Installation
1. Install lift cylinder in place using suitable slings or
supports, aligning attach pin mounting holes on the
upright.
2. Using a suitable drift, drive the barrel end attach pin
through the mounting holes in the lift cylinder and
the upright. Secure in place with the pin retaining
plate and 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 boom.
Using a suitable drift, drive the cylinder rod attach
pin through the aligned holes, taking care to align
the grooved pin holes. Secure the pin in place with
the bolt, lockwasher and nut.
5. Place boom in the stowed position and shut down
engine. Check hydraulic fluid level and adjust
accordingly.