Dang U-bolts!

I have never had a problem finding U bolts. Do you have a compressor? Maybe you could borrow a pneumatic impact gun. I have one with 750 ft lbs in reverse. It will either take them off or break them off. I would cut them off and use new U bolts. I agree with @RustyRatRod and others. No way I would reuse an old U bolt that is likely damaged.