Stripped the Bolt Head

SGBARRACUDA said
Or as in the case of a brake job I just did on a 67 Malibu, I used a chisel and hammer and was able to hit the bolt in the direction of loosening the bolt and they spun right out. had to do this on all four front wheel cylinder bolts.

Counter clockwise with chisel and hammer could work. Depends on how much rust and how solid the hammer blow will be. Worth a try