John deere 6310 hydraulic problem

[Rainbow tractor repairs]

The Scvs stopped working on my tractor .
They show 500psi when activated but go to 3000psi when the loader is lifted to max height.
Have stripped and cleaned priority valve block but that has not fixed the problem.
Any one help?

 

[Leejohn]

That sounds right. Put something in the bucket it well show more psi.