Bicycle Mechanics - Bolt just broke in half in the brake boss of new fork.

I got my new fork cut and prepared the other day and was just installing it. I was screwing in the bolts that hold my vbrakes on and one of the bolts just broke in half right at the brake boss. All but about 5mm of the bolt is now stuck in the fork. I was using a small hex wrench to do this, so I am guessing the bolt was somehow defective since I don't think it would be possible to generate enough force to break it normally. Is there anyway to get this bolt out? If not will I be able to replace the brake boss? The fork is a 2003 Rock Shox Duke XC UTurn.

Thanks.

Could try getting a dremel with a small bit and try engraving a slot into one end of the bolt and unscrewing it with a regular flat-head screwdriver?

Could try getting a dremel with a small bit and try engraving a slot into one end of the bolt and unscrewing it with a regular flat-head screwdriver?

I have a dremmel sitting right next to me. Does anyone think think this would be a bad idea for any reason? The brake boss is pretty small, so I am not going to be able to cut a very big hole. Thanks.

Yes, if it was that crappy that it stripped, DO NOT slot the head. As soon as you apply force with a flat head it will just strip. If there is enough bolt sticking out, soak it in penetrating oil (GT85, PB Blast), wipe the threads clean, and lock a small vice grip on the end sticking out. Slowly start applying pressure to back the screw out. no sudden moves or its easy to strip whats left.

Get an easyout from the hardware store. Sounds like exactly what you need.

Yes, if it was that crappy that it stripped, DO NOT slot the head. As soon as you apply force with a flat head it will just strip. If there is enough bolt sticking out, soak it in penetrating oil (GT85, PB Blast), wipe the threads clean, and lock a small vice grip on the end sticking out. Slowly start applying pressure to back the screw out. no sudden moves or its easy to strip whats left.

The bolt did not strip, it broke clean in half. Unfortunately there is nothing significant sticking out of the boss.

I know it broke, but if the metal was weak enough to break under the sheer force of a small allen wrench, the head with strip if you slot it and try to back it out most likely. you might get an easyout to work but I don't know if they will work on anything that small.

For as easy as it broke, this thing is quite strong... I tried drilling it and got no where. I tried slotting it, but it isnt going anywhere either. The brake boss has gotten quite hot now. Even if I get enough of a slot in the bolt has probably welded to the the boss now. An easyout isnt an option if I cant drill the bolt... Anyone have any more ideas? I could use this as an excuse to get disc brakes, but then I would need new wheels as well. That is just too expensive.

wow. hmmmmmmmmmmmmmmmmmmmmm.............

For as easy as it broke, this thing is quite strong... I tried drilling it and got no where. I tried slotting it, but it isnt going anywhere either. The brake boss has gotten quite hot now. Even if I get enough of a slot in the bolt has probably welded to the the boss now. An easyout isnt an option if I cant drill the bolt... Anyone have any more ideas? I could use this as an excuse to get disc brakes, but then I would need new wheels as well. That is just too expensive.

Easy out I say! Or disc's...

Easy out I say! Or disc's...

I need to drill a hole to use the easy out. The screw doesnt want to drill easily and while drilling I am going to kill all the threads in the boss.

You have to ask yourself... Do you *Really* need brakes?

You have to ask yourself... Do you *Really* need brakes?

I usually crash before I get going to fast anyway, so whats the difference ;) I am leaning towards going with discs, but need to pick a new set of wheels.

Hehe have you asked the LBS?

Hehe have you asked the LBS?

No, I just did this about 4pm today and havent had time to do anything yet. I might take the fork to them, but I usually do all of my own stuff and don't want to look like an idiot.. I don't think there is anything they can do unless the boss is removable.

jb weld an allen wrench to it then turn after a couple of days.

jb weld an allen wrench to it then turn after a couple of days.

Interesting idea. How runny is JB Weld? If it ran just a little into the threads I would not only have an allen wrench stuck on, but the bolt wouldnt come out.

There's supposedly a story about a tractor with a cracked engine block that was glued back together with jbweld epoxy and continued to work for 10 months. I'm not sure what the shearing strength of the epoxy but its worth a try. Just drown the whole thing in wd40 or some kinda penetrant to try to loosen it up first.

I try not to bring up experience to often, BUT, I have been a mechanic for twenty(20) years. Take this to someone that is experienced(This does not always mean a bike mechanic, a machine shop may be better) and have them remove it. If it broke on install it will probably come out without to much trouble but it is still best to pay someone that has removed a broken bolt 400 times rather than take the advice of a person that had a freind try it once.

I got my new fork cut and prepared the other day and was just installing it. I was screwing in the bolts that hold my vbrakes on and one of the bolts just broke in half right at the brake boss. All but about 5mm of the bolt is now stuck in the fork. I was using a small hex wrench to do this, so I am guessing the bolt was somehow defective since I don't think it would be possible to generate enough force to break it normally. Is there anyway to get this bolt out? If not will I be able to replace the brake boss? The fork is a 2003 Rock Shox Duke XC UTurn.

Thanks.Yes the brake boss is replaceable. I have the exact same fork and I removed my bosses when I mounted disc brakes. (Although now I can't find the flippen' things.)

For as easy as it broke, this thing is quite strong... I tried drilling it and got no where.

I don't know mountain bike forks, but if this is not a cheep item, I'd take it to a professional machine shop. They can drill down the center of the stub precisely without damaging the threads. Then it should be straightforward to remove with an Easy Out.

Yes the brake boss is replaceable. I have the exact same fork and I removed my bosses when I mounted disc brakes. (Although now I can't find the flippen' things.)

What did you or anyone else here use to remove the bosses? I tried using an adjustable wrench on an old fork and it had just enough flex in it to strip the head.

As a machinist I would guess that it would be cheaper to replace the boss then to have a machine shop get it out. I have never tried the JB weld idea but it sounds like it might work if you put a little on the end of the allen wrench and were careful not to get any in the threads. The hard part would be finding a way to hold it steady until it dries. Also if you are using a drill or dremel and it heats up let it cool down before trying to back it out. The heat will cause it to expand in the hole.

What did you or anyone else here use to remove the bosses? I tried using an adjustable wrench on an old fork and it had just enough flex in it to strip the head.
I thought this was a universally known fact <sigh>

NEVER USE AN ADJUSTABLE WRENCH IF YOU CAN HELP IT

If I remember properly it was a 9mm open end wrench. Take it to a Bike Shop NOW before anything else goes wrong.

I thought this was a universally known fact <sigh>

NEVER USE AN ADJUSTABLE WRENCH IF YOU CAN HELP IT

If I remember properly it was a 9mm open end wrench. Take it to a Bike Shop NOW before anything else goes wrong.

10mm is the smallest open ended wrench I have here. I stripped the boss on an old RST fork that really doesnt work anymore as a test before I touched good stuff. I have decided I am going with disc brakes anyway now, so I don't need the bosses. I might still want to take them off though. We'll see. I prefer doing my own maintanence, even if it does mean breaking things occasionally. I have had my whole mountain bike apart a few times and most of my road bike apart and this is the first real problem I have had. Thanks again for the help.

10mm is the smallest open ended wrench I have here. I stripped the boss on an old RST fork that really doesnt work anymore as a test before I touched good stuff. I have decided I am going with disc brakes anyway now, so I don't need the bosses. I might still want to take them off though. We'll see. I prefer doing my own maintanence, even if it does mean breaking things occasionally. I have had my whole mountain bike apart a few times and most of my road bike apart and this is the first real problem I have had. Thanks again for the help.
The smallest open end wrench you should have would be an 8mm although I've had a couple ofrepairs where a 7mm was needed but those were few and far between