I know the mechanic working on his car, he doesn't have internal pump knowledge.
I can confirm that (no offense intended to anyone); a few years ago I brought one of my pumps to him and wanted to get one of the external o-ring seals replaced (the size of a pencil eraser) where the timing advance lever attaches to. I was hoping to do it myself w/ his supervision, but he advised that I take the pump to a pump shop. DVST8R and I did it instead, and I learned a bit from it.
No one is ganging up on anyone here I don't think, but you are being fed bull *** from your mechanic, go find another (and get a Giles pump while you are at it :twisted: )