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I was installing a battery and ended up doing this while putting the clamp over the battery:

enter image description here

As you can see, I overtightened and the screw went right through the hole (I think?). The thing I'm referring to is roughly in the center of the photo.

Is there an easy solution to fix this?

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  • It looks like the head of the screw may have sheared off – did you end up with just a loose screw head? – dlu Jul 30 '16 at 4:08
  • @diu I'm honestly not even sure what happened, I think one of the pieces got lost somewhere in the engine so what you're saying seems to make sense. – Ser Pounce Jul 30 '16 at 4:15
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    If you have a tool similar to a dremel, cut a slot in it and then use a flat screwdriver. – HandyHowie Jul 30 '16 at 5:34
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It looks like what happened is that the screw head sheared off. Time for some investigation and ingenuity…

Without the head the screw is going to be a challenge to remove – unless the hole is relatively clean and/or you can get to the other end of the screw. If part of the screw is sticking out on the back side, it may not be too bad a problem. But one way or another you first want to find out if you can get something to hold onto the screw so that you can try to back it out.

First off, see if you can remove the part (the battery retainer?) that the screw was going through. Doing that may give you a bit more access to the screw from the top, and it looks like it might make it easier to reach around and try to get to the back of the screw. If you can do either, and can get your fingers or a tool on the screw, try backing it out. Getting it out even a little may make it possible to use a pair of pliers or vice grips to start turning it out.

If you can't get a hold on it, you may be able to tease it out with a screwdriver (don't press too hard, friction on the threads is not your friend), or with a drill running in reverse – or if you can find one, a left-hand drill bit or small mill.

If that fails, then do a search here (and there and everywhere) for something like "remove broken screw" or "extract broken bolt." Here are a couple of similar questions with answers that might help Is there a way to remove a broken screw?, Best way to remove broken bolt from intake manifold. Don't worry about where the bolt or screw is, the technique is basically the same.

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  • Thanks for the great post. Turns out if I remove the battery, I can get underneath it and feel it (a very small amount of it is exposted). Tried to just twist it with my finger to not avail and it was too thin and too hard to see for me to latch onto it with pliers (though possibly could work). Anything else you could think of in this scenario? – Ser Pounce Jul 31 '16 at 4:42
  • Why is this accepted solution when it did not work??? – Moab Jul 31 '16 at 21:42
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2 good solutions.

  1. Drill out the broken bolt (dead center) then chase threads with a proper sized tap. If I know the size of the bolt and thread pitch I can recommend finish size of the drill before tapping.

  2. Weld a proper sized nut to the sheared side of the bolt (weld internal of the nut), then use a socket on the welded nut to extract the remaining bolt.

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