Power Steering box leak on top?

My power steering box on my 69 barracuda appears to be leaking around the top cover and the castellated nut that is about 3 inches in diameter. This is the hemispherical cover where the adjustment screw is.

I just had the box out to replace the leaking steering wheel shaft seal. It was all so messy that maybe I didn’t notice it was leaking in two places. Now I have it back in and it is still leaking. Very disappointing.

Has anyone had this issue? What can I do? Can I tighten up the big castellated nut?