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How to Remove a Frozen Allen Head Bolt

Dakota Wright

Allen bolts can become frozen in place over time for a variety of reasons. Moisture that has come in contact with the bolt can cause rust to form in the bolt hole, or the head can strip out under certain conditions.

You may need a screw extractor when Allen wrenches won't remove an Allen bolt.

Removing the frozen Allen bolt may seem like a chore, however the do-it-yourself procedure is cheaper than taking the part to a machine shop.

Removing the frozen Allen bolt requires the use of common power tools and a screw extraction kit. Screw extraction kits are used to remove screws and bolts that have mixing or stripped heads and those that have rusted in place.

  1. Spray lubricant around the frozen Allen bolt and into the bolt hole if you can access it. Lubricating the bolt will prevent the hole from stripping out. If the hole becomes stripped, a kit will be required to re-thread the hole.

  2. Select a screw extractor smaller than the diameter of the Allen bolt. Look at the bottom of the package to determine the size of the drill bit needed. The drill bit needs to a slightly smaller than the diameter of the screw extractor. Metal working bits are the only type of bit recommended for this job.

  3. Drill a pilot hole directly in the center of the Allen bolt. The pilot hole needs to be drilled to 1/16-inch to 1/8-inch deep. You can drill through the socket impression on the Allen bolt if the head hasn't broken off.

  4. Tap the screw extractor into the pilot hole drilled in the Allen bolt. Tap lightly on the screw extractor to prevent breaking it, however force is necessary to make the extractor bite into the surrounding metal. Screw extractors have reverse threads that allow you to turn the extractor in a counter-clockwise motion to tighten it and then in a clockwise motion to remove the broken bolt.

  5. Attach the handle to the hex head on the screw extractor. Turn the handle clockwise to remove the bolt. You can use a crescent wrench on the hex head of the screw extractor if the kit didn't come with a handle.

  6. Tip

    Align a small punch tool in the center of the Allen bolt to start the pilot hole.


    Work slowly to prevent stripping the bolt hole. Stripping the bolt hole will require a kit to re-thread the hole.