Bolt Size for caliper mounts

What is the bolt size to remove the caliper mounts on the 2001 Chevy impala LS I have tried to remove them and my tool is just too big or too small Thanks! And another not so important question, when I purchased my car new, my spare tire would not fit in the hole to be covered up it seemed to big and still wont fit, how do I tell if it is an impala spare? Thanks
~William Burnett

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is the spare a full size tire or one of those small tires ?

what type of bolt is it and what are you using to try and remove the bolt.

It all depends what one you're talking about. Caliper itself? Or the caliper mounting bracket? Front or rear? It's been 2 months since I've been at work since I'm in school. But if my memory is right, I think the Caliper pins are 14mm, and the bracket bolts are 13mm. (Front). It might be backwards though.

If it is the hex type bolt head it is 60mm.