DocSween

I just want to say thank you to everyone for the great suggestions. I really appreciate your feedback. I probably should have posted an introduction in the new member forum before I posted here. I do not have enough posts yet for the system to allow me to post photo links. (I think it said I need 10 posts). Also someone sent me a private message but I will not be able to read it until I have ten posts.

My next step will be to take my bike to a local machine shop here in my small town. After reading your posts I know what to ask for. Thanks again, everyone!

rydabent

One more idea. Take a dremel tool with the very thin blade and cut a slot for a flat blade screwdriver. Soak the bolt over night in thin oil. Or better yet soak the bolt in a mixture of automatic tranny fluid and naptha. After lightly tapping in on the bolt to unload it, use the screwdriver to back it out.

206Moser

Hi,

I have a problem like the OP’s. A brake bolt has broken off in the canti boss of my Miyata 610. The break occurred below the rim of the boss, so I don’t believe I would be able to weld anything to the bolt without also welding my extraction nut to the boss.

I was thinking of using a combo of a left-handed bit and thermal expansion on the boss—guessing that the thin walls of the boss would heat quicker than the bolt, I was imagining a quick heat followed by a quick extraction.

What’s the benefit of heating the bolt itself? If I heat/cool the bolt, am I trying to create wiggle room in the boss threads?

Glennfordx4

If I was going to attempt that here I would try heating the post & cooling it down a few times before I would try drilling it out with a LH bit. Some canti post have open backs & with this type if you are careful enough you can drill it out and re thread it also.

Glenn

dedhed

Is a replaceable one? https://www.niagaracycle.com/categor...rs-silver-or-b

roadwing

If you heat everything up, quite hot, you may be able to break the rust bond between the bolt and the canti boss. It's a good start- it may create some space for penetrant to find it's way in. You can use differential cooling- heat everything, and then try to cool just the bolt. Probably jolts of brake cleaner with a red straw is the only way to get it cooled. The idea is to shock the bolt thermally, which MAY pop it loose. It's worked for me, a few times. If it does work, make sure someone's watching, you're going to look like a genius.

As noted above, you're pretty much down to left-hand drills to try to back it out. DO NOT USE AN EZ-OUT. If a left-hand drill won't get it, neither will an EZ-Out. Try to drill on-center, start small and increase. You're probably going to have to drill the bolt out entirely, and re-tap the threads in the boss. Left handers will give you a fighting chance to back it out in that process. DO NOT GET THE LEFT HAND DRILLS AT HARBOR FREIGHT. ASK ME HOW I KNOW THIS. Irwin makes a good 5pc set that you can find on the big shopping site.