'68 Valiant power steering gearbox leaking-Seal replacement?

I replaced the box in my car a year ago,i paid $150 from a local parts store.I have found over the years replacing the pitman arm seal isn't that hard but they ususally start leaking again because what happens is the shaft wears where it rides on the seal and even with a new seal it will still leak.The same goes for steering pumps,ran across that a few times also.So if it were mine i buy a new box,your Valiant is over 35 years old that's alot of wear and tear.Just my 2cents. :D