The description I used was "It sounds like a food blender full of marbles"
I replaced mine a year or so ago. Its a standard bearing that almost any bearing supply house will have in stock. (6202) When you push the bearing out, the new bearing must fit snuggly, if not, it will spin in the housing and make noise. If you don't weant to get fancy and make a sleeve, Use a piece of aluminum foil, lay it over the bearing slot, then push the bearing into the slot. The foil will act as a shim and keep the bearing from spinning in the slot.
Also, look at the seal, if it looks OK, leave it. Its job is to keep water out or any other crude out of the system, its not under pressure..
Heres a article with a lot of photos:
Leveler pump sounds like a food blender full of marbles – 1999 Southwind 35S
..