How To: Release a seized crank nut

This nut isn’t going to give up without a fight, but the trick is not to let it turn into a metal massacre...


1: It’s essential to hold the job tightly – for this well-seized nut I used a big chuck, bolted down – a good vice for round things. I’ve already tried a big spanner, then a socket and a long extension... no good.

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2: Shock often works better than leverage alone. With a well-fitting spanner, a few blows from a copper hammer can work wonders, jarring the nut free. But the nut’s a bit shallow to grip...

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3: Alternatively, it’s worth remembering that, if you’ve got an impact driver in your tool kit, it’s usually a half inch drive, so you can use it with a normal socket without any risk of it slipping off.

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4: No luck? Well, the nut’s the most replaceable part. It’s better to give up before damaging the crank. By drilling carefully part way through one side, a chisel blow easily split the nut free.

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