[Closed] Help... Stripped thread on post mount forks

try retapping it often works even if the thread is proper stripped (then use a bit of threadlock on the bolt next time), if that doesn't work then a helicoil.

this ^ is why post mount forks are a bad idea*.

bring back IS-mount please.

(*'they' are pushing post-mount [u]frames[/u] on us now FFS!)

Best bet for a Helicoil or Time-sert will be here:

http://www.cromwell.co.uk/aboutus/contacts/branches

Hth
Marko

RS sell helicoil kits. http://uk.rs-online.com/web/c/?sra=oss&searchTerm=helicoil&x=0&y=0. They've got a trade counter in Stockport or do next day delivery.

Try a engineering workshop. Retapping oftens works and i'd try it 1st, but the bolt hole isn't open ended so a normal tap will bottom out before a new thread is cut. You need a blunt end tap.
Or, you get a new stainless bolt, cut the 1st couple of threads off so its blunt and sharp. And carefully try tapping that in with a allen key.
Use lots of oil and blast the hole out with GT85. If that works use some bearing fit (you can get little blister packs from halforeds.)

Use a helicoil. simple and easy to fit and stronger than the original thread. I would not trust a retapped stripped thread in a brake

"I would not trust a retapped stripped thread in a brake"
Yes because if it fails the braking forces will the caliper against the fork, oh hang on a second isn't thats whats happening anyway? The bolts are only holding the caliper against the fork they are not resisting braking forces, so one bolt is enough anyway.
tapped it, if it feels right it is right.

Actually you are right all it does is hold the mounting surfaces together - that's all any bolt does. the friction between the mounting surfaces under the pressue is what holds the parts together, it could shear if it frets , it could wreck the caliper,it could fret and damage the lugs on the fork, if one bolt is no longer holding at all the other mounting will have twice the force on it as a sudden load and could fail = no brakes = you could tear a childs face off.

Brakes is one area not to skimp on.

A local engineering firm did my (IS calliper) thread, cost a £5er and they gave it to the apprentice to do.

cheers for all the replies.

Think I will go straight to putting a helicoil in as it sounds best in the long run.

Just to double check, I need a M6 x 1 kit, like [url= http://uk.rs-online.com/web/p/thread-repair-kits/7037169/ ]this[/url]??

For what it's worth I did something similar on a set of MX Comps about 5 years back and was looking to helicoil them but managed to get away with just using a longer than standard bolt - turned out there was plenty of thread at the bottom of the mount, but the standard bolts weren't reaching it.

I've been running the same forks since then without any problems whatsoever.

I got this kit was very easy to do [url] http://www.ebay.co.uk/itm/HELICOIL-TYPE-BROKEN-THREAD-REPAIR-KIT-M6-X-1-0-/250863247855?pt=UK_BOI_Metalworking_Milling_Welding_Metalworking_Supplies_ET&hash=item3a689d61ef [/url]

+1 for a longer bolt. Worked for me. But I did get flamed on another mtb forum for suggesting this. 🙂

sprocketjockey's got a good point. I stripped the thread on my totems but found that beyond the reach of my short bolts was enought thread to secure the bolt. I was pleased about that, as Totems don't have much spare metal around the mount to think about a helicoil.

sprocketjockey - I have tried/done this all ready, I stripped the majority of the thread with my previous brakes so put longer bolts in this time around and the remaining thread came out 🙁

So I think using a helicoil is the way to go.

+1 helicoil

then buy a torque wrench 😯

Right, sorted it... bought [url= http://uk.rs-online.com/web/p/thread-repair-kits/7037169/ ]this[/url] and it did the job perfectly, very easy to use. A small bit of drilling, hoovering, tapping, hoovering then installing helicoil worked a treat.

Now... who's got a spare torque wrench I can get on the cheap? 😀