Hydraulic leak problem JD 300 Industrial

[hamp34]

Hi everyone!

I have a jd 300 Industrial tractor backhoe and loader I am having a leak from the pressure control valve I have replace every seal / o-ring on the valve and it still looks like it is leaking from the casting Has anyone had a casting pinhole / crack in that valve before?
It is leaking from where the black arrow is pointing which is behind the little alcove

 

[beenthere]

Without checking further, but reminds me of the fitting someone was talking about a couple days ago.. that had a couple o-rings between the casting and the fitting.
The OP was asking to help identify the fitting (think decided it was a flow control) and if there was a gasket leaking.

What have you found behind this control valve? gasket or o-ring?

 

[hamp34]

o rings are behind the valve and all of the seal / o-rings have been replaced it is not leaking from any line attaching point

 

[furnone]

I had a pinhole leak like that in my JD 400 Industrial. My Bro-in-Law welded it for me.