My panasonic CB2000 frame has welded on brake bosses. A bolt (alloy) failed and the treaded part is stuck inside. No part sticking out to grab with pliers or vice grips. Is there any way to remove it? The bosses are not the screw in type.
by Karel_Oh
3 Comments
If you have a dremel, you can grind a flathead slot into the bolt stump. That often works well.
A bolt extractor set is a good start. You drill a hole, then insert an auger that’s left-hand threaded, so as it tightens and bottoms out you apply a loosening twist to the bolt.
You can also get a drill that’s close to the bolt size, and drill out most of the bolt diameter-wise. Sometimes, it’s easy to scrape the rest out. Other times, you can chase it with a tap that matches the bolt size. Luckily, it’s not hardened.
For drilling, it helps to have a sharp punch to create a crater, for your drill to start in. I would grind or file the spikey part down, to give yourself some flatland to start from.
Some other techniques include penetrating oil, smashing the bolt inward with a hammer and punch to break anything up, and super-heating the bolt to red-hot to try and break anything up. Sometimes people put a nut over the bolt stump, then weld the bolt onto the nut and turn it. (I know that’s probably not feasible in this case, but it’s interesting.)
I’d go with a screw extractor for that, but not before soaking it for a few days with a very strong penetrating fluid, and applying some heat to absolutely ensure it’s not stuck
Thanks! I’ve ordered a extractor set. Also have access to a drill press at work so drilling it out will be the alternative.