How to stop a leak

How to stop a leak

I have a Demon with power steering. The problem I'm having is the steering gearbox has a leak coming from the pressure return valve area. I replaced the two o rings. Reinstall still leaked... A little worse. Took it back apart. Dried the mating surfaces. Applied rtv... Let it dry overnight. Start it up. Didn't leak. Turn the wheels lock to lock....Took a look....Leak still there. Anyone else ever had this problem and what was the fix?