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V-Brake bolt stuck inside another bolt which screws inside a bit welded onto my frame

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V-Brake bolt stuck inside another bolt which screws inside a bit welded onto my frame

Old 08-11-09, 09:32 AM
  #1  
ortsa
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V-Brake bolt stuck inside another bolt which screws inside a bit welded onto my frame

Hi All,
While removing my old v brakes one of the bolts was unusually stiff so i kept going and another bolt with screws directly onto the frame came off with it, it seems impossible to remove this bolt, iv tried holding it in a vice but with such a small ammount of metal to grip onto(except the thread which i dont want to ruin) i fear it may be impossible to remove.

Has anyone else encountered this problem? How did you fix it? Does anyone know where i can get a replacement bolt from?

Thanks all
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Old 08-11-09, 09:58 AM
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ginsoakedboy
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Hard to say exactly without pictures, but what I think you may be dealing with is the mounting bolt for the brake arm is frozen into the brake boss by corrosion or cross threading. (I think what you are referring to as the second bolt that screws into the frame is actually a threaded brake "boss" -- in some cases these are threaded, in some cases they are a fixed part of the frame. Their function is to serve as the pivot point for the brakes). I would try a penetrating lube like Kroil, PB blaster, Liquid Wrench to try to free up the bolt that holds the brake arm to the boss. The mounting bolt and the threaded brake boss are standard parts for which you should be able to find replacements if you can't get them unfrozen and need to destroy them to get the brake arm free.
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Old 08-11-09, 12:00 PM
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Mondoman
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dang -- I've got a long-lost twin out there! Good advice, gsb!
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Old 08-11-09, 01:07 PM
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w98seeng
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Penetrating oil will help some times, but I have found it won't if the thread is screwed up.

If you can still get the hex key in there, try tightening it a bit. If it is broken off, try using a locking wrench (Vise Grip) to grip it (unless it is broken off flush with the mount). Work it back and forth, a 1/4 turn at a time then a bit more and more until you have it turning a complete revolution in each direction. By this time you should be able to turn it out.

If all else fails, an LBS can drill it out and re-tap it with new threads.
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Old 08-11-09, 02:08 PM
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Panthers007
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Same thing happened to me. A 9mm flat-wrench unscrewed it. Reason it happened: The Ape who built my bike cross-threaded the v-brake bolt in the boss. No small, thin wrench? Go to a bike-shop. Takes a minute to pull it and thread the boss back in. Use some blue Loktite.
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Old 08-11-09, 10:01 PM
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desertdork
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It sounds like my experience was similar to Panthers0007.

I didn't actually remove the threaded cantilever boss from the frame. Rather, once I noticed it was turning, I held the boss steady a thin wrench (like a cone wrench, 10mm?) on its barely visible flattened sides while I loosened the mounting bolt with a hex wrench. The boss that's stuck in your brake arm probably looks like the one in the picture, right? The flat sides at the base of the boss aren't as easily seen when the brake arm is sitting on it. It might even be easier to thread the whole deal back into the frame while you try the two wrench technique.
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