how about a pipe wrench(small one) one that will bite down into the metal and grab it without it slipping.. go to ford and get a new one and then use (if i can remember correctly) a 15 mm box end wrench on it.. make sure you are turning it to loosen it and not tighten it.. pretty common error when upside down people tend to go the opposite direction, forget which way they are turning due to the upside down position???? hope this helps.
