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2007 JLG Boom Lift Platform only rotates one direction

Joined
Oct 14, 2022
Messages
11
Location
Sandpoint Idaho
I have a 2007 JLG Boom Lift. The platform does not rotate or rotates very slow to the right(intermittent changes when machine is shut off) and but work fine in the reverse direction.
The boom lines were recently replaced. (The lines run continuouse from the main control valve to the rotate actuator motor assmebly. No internal check valves). The control valve coils for the platform rotate were replaced. The platform rotate actuator was replaced. The platform rotate check valve cartridge was replaced.
After the platform rotate actuator motor assembly was replaced and that did not fix the problem I spend a good deal of time troubleshooting this problem.
When I reverse the lines to the platform rotate actuator, then platform will not turn the opposite direction.
When I swap the platform rotate lines with the platform level lines the platform rotates in both directions but the platform level function will not work in one direction. This also will reverse when I swap these lines. Plumbed one way it will not tilt up the other way it will not tilt down.
No change when I swapped the platform rotate control valve assembly with the platform level control valve assembly.
When I swap the electrical plug that actuate the control valve coils the controls are reversed but the platform continues to not rotate in the same direction. No change in direction of non rotation with the controls being reversed.
The ground controls produce the same results in all cases
I swapped the platform rotate relief valve cartridge with the platform level cartridge with no change.
When the plarform attempts to rotate the pump pulls hard and the appropriate line to the actuator moves with pressure. The platform will spring back.
It is like the line has pressure but the pressure is not allowed to go back to the reservoir.
I do not know what I am missing. Any help would be appreciated.
 

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Joined
Oct 14, 2022
Messages
11
Location
Sandpoint Idaho
We checked the voltage from the function switch to the control valve controls. 13.64vDc
We checked the pressure coming from the control valve at the platform rotate actuator motor. More than 1000 psi on each line when control valve is actuated.
We swapped both ends of the hydraulic lines servicing the platform rotate actuator motor assemble and the main control valve assembly to rule out a damaged line that would only allow fluid to flow one way. No change platform will not rotate to the right.
We blew out the ports from the control valve to the platform rotate check valve and from the control valve to the fittings connecting the hydraulic lines to the platform rotate actuator motor. There were no obstructions, again no change of condition.
We changed the control valve a second time using a control valve from the boom extend/retract(same part #) boom extend retract works with the previous platform rotate control valve and the platform will not rotate to the right with the swapped valve. Have tried 2 other valves known to operate from other functions. Still will not right rotate unless i swap the lines at the platform rotate actuator motor then the platform will not rotate to the left.
If we crack the not pressurized line at the platform rotate actuator motor the platform will rotate to the right dumping the oil in a bucket. This line of course has to be tightened to rotate to the left as this is the pressurized line for the left rotation.
Any ideas would be greatly apprecated I now do not know any other sets to take
 

djking

New Member
Joined
Apr 26, 2024
Messages
1
Location
Oklahoma
I have this same exact problem. Tried everything you did too. Did you figure out what was wrong?
 
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