i had the same problem with mine last nite (didnt break the socket, just rounded the nut a bit), socked it in crc and half hour later came back, instead of undoing it i tried doing it up a little first (slightest bit) and then hit the dump pipe with a small hammer near the sensor, sparayed a bit more crc and another half hour later came back again and it came out. althow i wont be able to use the nut again as it folded in whilst i was undoing it (didnt matter as i welded a new one in my new dump).