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A couple of years ago I tightened the bolt attaching my rear mudguard/fender to the eyelet at the hub and it snapped, leaving a 5mm long section of bolt stuck in the thread. Since then I've tried various things to get it out, all ending in dismal failure. So I've had to use the less effective type of mudguards that are strapped to the stays with cable ties.

I tried:

  1. Getting at the small amount of protruding metal with small pliers: not enough metal to grip it

  2. using a threaded bolt extractor of this type: there wasn't enough thread exposed on the other for the extractor to get a grip

  3. Trying to drill into the middle of the bolt: the drill bit broke!

Any ideas appreciated!

The frame is aluminium. The bike is audax/sportive type.


Update: I tried everything suggested, except the blowtorch, to no avail. So I gave up and got a new frame, something I 'd been thinking of doing for a while as it has been showing its age.

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2 Answers 2

up vote 7 down vote accepted

You could try slicing, with a dremel or similar instrument, a 'notch' into the bolt that would allow a flat edge to fit in. Soak the bolt/area with a penetrating lubricant (PB Blaster or some such) or ammonia, let it sit and do its work for a few minutes (some folks recommend 24 hrs), and then attempt to 'tighten it through' the eyelet.

You could also try to heat it w/ a propane torch for 30 seconds or so and then try again to tighten the bolt through eyelet.

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1  
what I like about your answer is that it gives me an excuse to buy more tools. The dremel method sounds like the most plausible to me. –  Jonny Cundall Sep 3 '10 at 12:13
1  
we use the dremel w/ a nice small cutting wheel alot. Be sure to get some grinding/polishing bits as well! haha. –  tplunket Sep 3 '10 at 13:05

Take the bike to your local automotive repair/machine shop. Bolts into a blind hole with the head sheared off is a common automotive problem. They will have tools to take care of this problem. 5mm is on the small side for automotive bolts so you may have to contact more than one shop to find one with a screw extractor (aka easy out) for 1/8" or 3/16" bolts.

Edit: Reading your question again (and following the link this time) I see that you are already onto the easy out idea. What the automotive machine shop will probably be able to do that you cannot do at home is to use a drill press to create a small hole in the middle of the stuck bolt. That small hole will give the screw extractor more surface for a better grip.

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