Help!! I can't the old battery out! That long bolt on the right side of the battery, which attaches the hold-down clamp (or whatever it's called) to the car, is just spinning and spinning, but isn't loosening in the least. The entire bolt is spinning, including the bottom part that is in contact with the hold-down clamp. Is there some trick to getting this thing out? Thanks.

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2003 X5 4.4i
1992 Porsche 968
2007 328i
2014 Subaru Forester XT