I pulled pump and driveshaft to replace carbon ring, floating ring and bellows. Question is, of course the driveshaft has some rust looking stuff and corrosion, with driveshaft on bench trying to test fit the new floating ring and slide it on all the way behind the snap ring groove to make sure it goes on easy when I get it in the ski...it’s very hard to do it even out of the ski. I’ve sanded and cleaned the shaft best I can. Is this normal or do I have to replace the driveshaft or find someone to turn it and clean it up?