Just throwing this out there; a company called Cano out of Atlanta I believe sells a penetrant called Kroil, the oil that creeps. The smell is terrible, but do you want that bolt out or not. It blows away blaster hands down! I've never seen anything come close. You can find it locally, or from Eastwood. I buy it by the gallon. It also comes in quarts, & spray can. Try it, you won't be disappointed. Larry