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Q: I was changing my alternator and I stripped the last bolt really badly, what do I do to get it off?

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I was changing the alternator in my vehicle. I got all the bolts off that I needed to get off except for the last one on the bottom. I have been trying for hours to get this bolt out that I have stripped the bolt badly. How do I take it off?

My car has 87567 miles.
My car has an automatic transmission.

A: Hello, thanks for writing in. I’d be happy ...

Hello, thanks for writing in. I’d be happy to help.

If ANY of the head remains, even if it is completely mangled, there are tools that can grasp the mangled head and remove it. If the bolt is spinning in place and won’t thread out, you have to create pressure under the head (prying motion) WHILE backing it out and hope that the bolt catches enough to thread itself out. If that doesn’t work, it has to be drilled out, which is no big deal if there is adequate room. If the female threads are damaged at the end of any of these attempts, you have to install a helicoil. In the worst case scenario, if you have damaged a bolt hole that is in a part that is not accessible to a drill and re-threading tool, you end up having no choice but to remove the part off the car so it can be repaired. Again, no big deal...this happens every day.

If you would like help with this, consider having an expert automotive technician from YourMechanic come to your home or office to remove the bolt for you. The technician will have the right tools to complete this task.

To avoid this problem again, in the future if you suspect a bolt is stuck, first tighten it a LITTLE, just a crack, then loosen a little. Keep wiggling the bolt back and forth just a hair in each direction. You are trying to break the seal (the rust bond). As it gets freer (it will, if you are patient), with this minimal wiggling in each direction, move it just a little bit more each time, particularly in the loosening direction. Eventually, it WILL feel free enough that you can loosen normally. The key is to go slow. Removing stuck bolts actually requires a strategy. If you just loosen it as it it were a "normal" bolt it will break every time. I know because I used to break it every time. Like everyone, I learned late in the process.

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