This weekend I went to replace what was left of the metal battery tray in my 81 242. Between the acid and rust the heads of the 13mm bolts that held it in had been reduced to 3/8" dia. circles. I thought I would have to drill them out and tap the holes, the tray has recesses and there's no way to get anything but a socket on the bolts even in the best of circumstances. Went down to Sears and for 20 bucks got a set of Bolt-Outs. They fit over the head of the bolt and a socket goes over both and you turn w/ a ratchet. I didnt have much hope, but they turned the suckers out like they were brand new and greased. Highly recommended, good luck whatever you do.