That happened to a bolt on the left side of mine. I cut it off with a small cutting wheel on a Dremel tool. I still haven't replaced it, but it doesn't seem to make a difference (yet). If you go this route be sure to cut a little, let it cool or cool it with water, cut a little more, cool it, etc. or the bolt will heat up & start melting the plastic. NOT GOOD on a fuel tank! :scream:
Good luck!