Miguel,

Try a hand held impact driver.

Smack the hell out of it with a hammer, and it usually will break
anything loose.

But above all else, be sure to use impact sockets, so they won't have
the tendancy to round off the heads of the bolts !!

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Terry--
74 Campmobile- (Clementine)
85 GL- (Delilah)
86 BMW 325 ES- (Eva)