Brake bolt thread broke

[StevenE]

Hello all,

This sunday I started installing the front brake disc. I cleaned all the 5 bolts as good as possible, did some thread locking compound on them, and bolted them in the wheel. I used progressive torque augmentation and a criss cross pattern. At the end, when I was at about 18 ft/lbs (maximum is 28 Nm, and 18 ft/lbs is under that) I rechecked all five bolts with the torque wrench, and on one of them the thread snapped during this checking round. It's the inner thread of the wheel that snapped.

Darn, seem like the soft metal of the wheel is prone to this, although I stayed under the maximum torque. So, are their alternatives to mount this one bolt in the broken disc inner thread?

Using a bigger diameter and thus re-threading the wheel seems like a difficult option, since it would also require to enlarge the diameter of the mounting hole on the disc.

I thought of a larger bolt (larger length) and using a nut on the inside of the wheel. It might take some patience to get the nut on the inside of the wheel, but it seems do-able to me. Question is off course if this setup is safe, since there are 2 major forces applying on the bolt: the one leaving the head of the bolt holding the disc tight against the wheel and one in a 90 degree angle on the bolt axis when applying the brakes.

Anyone had this and are there other safe solutions than buying a new wheel?

Thanks a million!

[Dom]

It's getting late so I couldn't totally understand what you were saying but you could proly just helicoil it.  www.helicoil.com

You might be able to find a kit at your local nut/bolt store.

[red_phil]

MAybe it's just me, but I wouldn;t trust a helicoil to hold on my front brake disc!  

[John Bates]

[werase643]

i like 5 and 1
4 bolts will hold the rotor on
but if you are worried about how it looks....buy a new wheel

[Mk1inCali]

Find a new/used wheel.  Even if it costs you 300 bucks...won't it be worth it to know that you are riding something that is SAFE, and reliable?

[StevenE]

Thanks a lot on the info. I'm still searching, but I guess it would be solution 3, then 2 and finally 1. I don't like 5 and 4 seems a tricky one too. The thing is the bike has a lot of milage, is 12 years old and I don't want expenses to grow on it since I'll probably get rid of it in 1.5 years or so. BUT, I still want to ride safe!

[MarkusN]