MF 590 lift issue

Hello, I have an MF 590, when the tractor is running, the quadrant controls will not lower the rear lift, they are up all the time. I know that the selector valve controlling lift position is stuck. Have tried to free it out by taking off side cover and moving the walking beam.
As it is multi power I do not want to split the tractor. Is there any way I can bypass the quadrants and use a spool valve to operate lift position.
Any advice greatly appreciated.

Stumped me ...but welcome to Net Tractor Talk.
The rear normally does not have any down pressure, gravity takes it down, but if the controlling valve is stuck, yep, no way would they come down. Someone smarter than I should be along shortly.