A trick to removing stripped Allen-key bolts can be a game of 0.003 inches


Recently, I described my adventure of Buying Back Bertha, which may sound like the title of a comedy but centered on repurchasing the 1975 BMW 2002 that I had sold to a friend nearly 30 years ago.

This is a companion discussion topic for the original entry at https://www.hagerty.com/articles-videos/articles/2018/07/09/removing-a-stripped-allen-key-bolt


Sounds like you’ve just started doing mechanical work. Much better methods once you progress


To remove a stripped (or stuck) allen head bolt, I found that inverting a can of Gasduster keyboard cleaner and spraying the very cold liquid into the hex hole for 20 seconds followed by a sharp rap with a small hammer to the socket mounted hex wrench allowed the screw to be removed easily.


The bolts in the photo are Torx heads, not Allen head. These are very common on German cars such as Audi and BMW. Replacement bolts usually come with a dab of something that resembles blue Loctite so they can be a pain to remove, but you do need the right tool.


@kf21857 - The bolts in the article are indeed Allen head. Torx headed hardware does not have the flat internal edges that allow the shim trick to work.

Torx hardware has gain popularity on vehicles from many modern manufacturers, both internal and external Torx heads. They can be a real pain if they strip, but you are correct that with the proper tool and preparation they typically do not strip.


@kf21857 I think the Torx heads you are referring to in the picture are the ones that hold the caliper together, while the Allen head bolts that hold the caliper to the hub are on the back side, not pictured.