Unscrewing a broken bolt

Sometimes a bolt can break while trying to unscrew it, or the head of a screw can get stripped. In these cases, the solution can be a conical extractor.

To unscrew the bolt, you will need to mark the center of the remaining thread with a center punch, then drill a hole that allows you to insert the extractor of the appropriate size for the bolt.

Once inserted, unscrew as if you were normally unscrewing the bolt while applying slight pressure. This way, the extractor will seat itself in the hole and unscrew the broken bolt.

Plastic bolt

This method works perfectly for bolts made of any material. In this case, we extracted a small plastic bolt located on the radiator reservoir of a BMW. This very delicate bolt serves as a valve in case of overpressure inside the reservoir.

In this case, the extractor penetrated deep into the threading since the material is very soft. To use the extractor, we mounted it on a drill driver, but it can also be mounted on a tap wrench.

Once removed, it was easy to screw in the new bolt without over-tightening.