Bought the bike used. When I changed the filter this morning, it felt like the filter drain bolt was loose, though I've never noticed it leak. Put it back together, and it seems the drain bolt won't stop turning. I know it isn't stripped, when I take the cover off the screw goes in fine, seems like its just too short or something. I can't pull the bolt out with pliers, so it is grabbing something... But am I missing something?