Some bolts just won't move. They are stuck, seized, stubborn, frozen ,rusted, corroded and otherwise impossible. use a penetrant like PB Blaster, Liquid Wrench or WD-40, to get it free you need to apply heat with flame of a propane torch. Be careful with an open flame! Never use an open flame near a fuel or brake line, rubber, paint, trim, fabric...use your brain use a 6 Point wrench or socket on your seized nut/bolt. Try to rock the bolt by tightening and loosing. If you can help it, avoid 12 point wrenches and sockets as they have less grip and are likely to slip and strip the bolt we are working on