Stellar® EC Series Crane Owner’s Manual
do not move while operating the crane.
• Determine the function that is operating on its own. Check to see if there is power going to
the solenoid valve from a function that should not be operating. If voltage is present at the
solenoid valve without operating the function, the toggle switch has failed and is stuck in the
“on” function. If no voltage is present, the solenoid valve may be partially open. Remove
the stem valve, thoroughly clean, lubricate, and reinstall the valve. Do not over tighten. If
valve will not close, simply replace it.
Problem: Winch will not lift load.
Solutions:
• Make sure that the object being lifted does not exceed the rated capacity of the winch.
Refer to the capacity chart. If the object is within the rated capacity, reposition the truck
and try to lift the object without using the crane boom extensions. Refer to “Crane Hoist
Troubleshooting” later in this chapter.
Problem: Crane operates slowly.
Solutions:
• Check the level of hydraulic fluid in the reservoir. Add fluid as needed.
• Check hydraulic fluid temperature.
Problem: Winch “Up”, Main Cylinder “Down”, and Extension Cylinder “Out” are the only
functions that don’t operate.
Solutions:
• Make sure that the anti-two block limit switch on the end of the boom is adjusted properly or
operating per adjustment (If applicable).
• Make sure that the limit switch is working properly. Disconnect the two wires connected to
the limit switch and tie them together. If all functions operate, replace the limit switch.
• Make sure that the cord for the cord reel is undamaged. Check the continuity of the cord.
Disconnect the cord reel from the crane harness and bypass the harness connection. If the
crane operates properly, replace cord reel.
Problem: Cylinder drifts outward or downward.
Solutions:
• Check to see if there is air in the hydraulic system. Operate all cylinders connected to the
hydraulic system. Start with the extension cylinder, then operate the main boom, winch,
rotation, and ending with the hydraulic stabilizers, if installed. When operating, extend each
cylinder halfway out, retract all the way in, and then extend until the cylinder rod is at the
end of its stroke. Operate cylinders slowly so air is pushed thru the system to the reservoir.
Repeat this cycle 2-3 times.
• Make sure the holding valves are operating properly. Note: Before performing any
maintenance on hydraulic components, relieve hydraulic oil pressure from all hydraulic
circuits. Remove, clean, and then inspect each holding valve. When removing a holding
valve, always relieve the pressure inside the cylinder by loosening jam nut of the holding
valve and turning set screw inward/clockwise. Count the number of turns until the set screw
is seated. When reinstalling the holding valve, make sure the valve is reset by turning the set
screw the number of turns it took to relieve the pressure. Finish by tightening the jam nut.
• Check the cylinder rod for scratches. If a scratch is located on the cylinder rod, hydraulic
fluid can pass thru and cause a loss of pressure. Replace cylinder rod or cylinder.
• Check to see if the piston seals are damaged. If they show signs of damage, install a new
cylinder seal kit.
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