Well It Leaks AGAIN!

Dana67Dart said
how is the surfaces it is sealing against? Polished, smooth or a groove worn in from decades of use? was it turned at any time? what does the old seal look like when you take it out? PHOTOS when you get back?

So true. You can replace main seals until you turn blue in the face, but you are wasting your time if the sealing surface isn't right.