Advice needed: It's either corrosion or a gorilla with a wrench, or both, but I cannot get the brake caliper bolts on our Ford Explorer out. FoMoCo exacerbates the problem by using bolts with shallow heads, so it is difficult to keep a socket on them. I have tried various penetrating oils such as PB Blaster, smacking the bolt heads with a medium hammer, etc. to no effect. More info. in my 1st comment...