I recently replaced an Oberdorfer pump for the presoak on my Mark VII to the tune of $600. I would like to rebuild the old one and keep for a spare. Does anyone have a good idea on where to buy a kit? According to my distributor Mark VII doesn't offer a rebuild kit and the pump is made for Mark VII by Oberdorfer, so I don't have a Oberdorfer model #. My machine is a GT500 about 7 years old.