JLG 150HAX Service Manual - Manual (Page 102)

SECTION 5 - HYDRAULICS
5-6 – JLG Lift – 3120817
Main Lift Cylinder Removal
1. With tower boom at horizontal, depress plunger on
limit switch in main lift circuit, located inside turnta-
ble. Keep plunger depressed with a c-clamp. Raise
main boom above horizontal, just enough to be able
to access main lift cylinder. Attach a suitable support
device or devices to main boom.
NOTE: When raising main boom with tower boom at hori-
zontal, do not completely raise main boom, as tip-
ping may occur.
2. Remove four bolts and lockwashers securing main
lift cylinder rod end attach pin to boom. Using a suit-
able brass drift, drive attach pin from main boom.
3. Using auxiliary power, retract main lift cylinder com-
pletely.
4. Remove four bolts and lockwashers securing main
lift cylinder barrel end attach pin to tower boom.
Using a suitable brass drift, drive out attach pin from
tower boom.
5. Remove cylinder from boom and place in a suitable
work area.
Main Lift Cylinder Installation
1. Install main lift cylinder in place using suitable lifting
slings or supports, aligning barrel end attach pins
with holes in base boom.
2. Using a suitable brass drift, drive barrel end attach
pin through mounting holes in base boom and cylin-
der barrel end. Secure in place with four bolts and
lockwashers.
3. Remove cylinder port plugs and hydraulic line caps
and correctly attach lines to cylinder ports.
4. Using auxiliary power, extend cylinder rod until rod
end aligns with attach pin holes in main boom.
Using a suitable brass drift, drive rod end attach pin
through aligned holes, taking care to align pin
retaining plate holes with holes in main boom.
Secure pin in place with four bolts and lockwashers.
5. Remove supports and lower boom to stowed posi-
tion. Remove c-clamp from limit switch to release
plunger. Shut down engine, check hydraulic fluid
level and adjust accordingly.
Lower Master Level Cylinder Removal
1. With tower boom partly raised and properly sup-
ported, prepare to remove lower master level cylin-
der.
2. Remove bolt and lockwasher securing level cylinder
rod attach pin to base end of tower boom. Using an
appropriate brass drift, drive out level cylinder rod
attach pin.
3. Tag, disconnect and cap hydraulic lines to level cyl-
inder and disconnect supply lines from turntable
swing motor.
NOTE: When disconnecting hydraulic lines, any residual
hydraulic fluid should be drained into a suitable con-
tainer.
4. Make up two temporary hydraulic hoses to carry
power from swing motor supply lines to lower mas-
ter level cylinder. Couple temporary hoses to swing
motor supply hoses and to lower master level cylin-
der. Plug ports in swing motor.
5. After installing temporary hoses, use auxiliary power
and activate swing function to fully retract lower
master level cylinder.
6. Remove temporary hoses from lower master level
cylinder and cap them. Plug cylinder ports.
7. Remove bolt and lockwasher securing barrel end
attach pin to turntable. Using a suitable brass drift,
drive out barrel end attach pin from cylinder.
Remove cylinder from turntable.