Replacing or rebuilding a Federal PS pump.

Greetings.

I have a Federal pump on my '69 NY (original 440 with only 60K) which is slowly crapping out. It's leaking slightly from the seal behind the pulley, and the shaft has some end play (very little, but you can hear it even with the belt still on). The leak is minor now, but I'm sure it will get worse.

There are rebuild kits, but should I replace it or rebuild it? Are there reliable sources for new/rebuilt pumps? Also....how does it come apart?