Bob,

Are you sure it is leaking from inside and not form the line? Since you have had it on and off, did you use new washers on the line? Just a thought.

They are pretty simple and if the inside walls and piston look good and you have new o-rings, don't know what else it could be?

Where in Alexandria are you? I'm right off 395 at King, but stay in Annapolis alot at my GF house.