it sounds like you might have trashed the head of it.fyi next time make sure you have the correct socket and only use a 6 point one and lube it up the day before with a rust penatrtor........try like we suggested and see if you can get a sawsall in there.......i believe the bolt goes into one of those sliding clip nut things like the ones that hold the bed on!

and not to sound like a nag.....but make sure you replace the slave cylinder!!!!!!!!!!