Hi, I am a professional certified mechanic, with an engineering background, and 35+ years experience. I will do my best to assist you. Also keep in mind I don't know if you are a pro or a novice so we may have to fine tune the answer. Feel free to add any additional info you feel is needed as we go on. Always keep in mind that I am here to help you with any questions.
Sometimes you can force a screwdriver under the head of the bolt, prying outward on it, as you try to back it out. Worst case scenario, you can grind the head off of the bolt, and use a punch to drive out the remains of the bolt. From there you can use a bolt and a nut in place, or go one step oversize, and drill then thread the hole with a tap, to the next size larger bolt. A grinder like the one at the link HERE would probably be a good choice to use to grind the head off of the bolt. Grinders like this can remove a bolt head in just a few minutes. If you have any more questions, as always, I am here to help. Good luck with it, have a great day, and Thanks for using Just Answer.
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