Wrong Type Valve?

[Kaliburz]

Here is a dumb test. Switch the quick disconnect hoses.

If your mower still goes down, then most likely be your seals. If the mower raises, then you know your control valve is "leaking". I had that happen on a tractor once. One side would leak so it would slowly extend or retract the cylinder depending on how it was connected.

Now cycling the cylinder XX times should remove the air. Depending on location of the ports, you should keep the ports high so the air will "float" to their location and in theory, get cycled out.

 

[J_J]

Cyl don't normally move when all valve levers are in neutral, and the centering springs are doing their job, as the fluid has no pressure or very little pressure from pump to tank..

Moving the spools and having something provide resistance is what causes the pressure to be developed.

 

[Kaliburz]

Cyl don't normally move when all valve levers are in neutral, and the centering springs are doing their job, as the fluid has no pressure or very little pressure from pump to tank..

Moving the spools and having something provide resistance is what causes the pressure to be developed.

Correct, they don't....when everything is working correctly or not worn (but w/ it being new....it should not be an issue).

Wait, Kubota's are open center hydraulics aren't they. I forget more and more tractors are open center now a days.

My old Deere is a closed center system and the factory installed control valve had issues. OEM Deere's different then the traditional push/pull hydraulic valves. Being closed center, you have at least 2000psi available all the time....

But still, if it's not the valve, then it probably is the seals in the cylinder. Just because it's new....doesn't mean that something isn't bad.