Stripped post mount thread on fork lowers……

Some ham fisted maintenance has lead to me stripping the thread out of my lower post mount for the brake calipers.

Any tips for getting a bolt to stay in, is it just a case of loading it with threadlock and hope I don’t need to take it out in a hurry??

Or find the longest bolt I have and hope to find some usable thread further in??

Or a combination of the both??

Any suggestions welcome

A longer bolt will often work.

You need to get a ‘Helicoil’ in there. Your LBS may do this if they are good, failing that local car mechanic.

It happened to me. I used threadlock and it was fine. Eventually took it to a local engineering company who helicoiled it for the price of a couple of bottles of wine and some biscuits. Which was very nice of them.

Any of the above or permanently loctite in a stud and use a nut to fasten the caliper.

Helicoil – its a permanent and strong repair

cheers folks……

thought helicoil might be the preferred solution.

Although liking Hamish’s idea,

So no need to ditch the lowers yet!!!

If the thread’s actually stripped, don’t bodge it by just threadlocking anything in- either a stud or a bolt, doesn’t matter, threadlock will stop a bolt from loosening but it won’t replace the thread.

Since it’s the bottom one, hopefully a longer bolt will do it.

A longer bolt will often work.

And if you are real careful may also split the lowers…

My tendency would have been to agree with Northwind but when a careless stoker allowed a pedal to unscrew and knacker the thread in the crank I took Loctite’s advice and it’s been OK for years now, so go ahead – but the stud idea sounds even better. And it’s amazing what can be done with epoxy these days in extreme cases.

Put something into the hole see how deep it is, then see what amount of the original screw goes into the hole, to get an idea of how many threads are damaged and might be left.

I would screw a longer screw in by hand and see how much purchase it has, try the simplest options then move onto the more complexed / time consuming.

Heli coils are a good kit to have, but at £30 to £40 for a decent sozed kit, not too good if you only use them every now and then, I have the imperial and metric kits.

So basically I’ve just said exactly what everyone else said 😀

Well plenty of options there cheaper than shelling out a couple of hundred on a new set of lowers.

So will try a longer bolt tomorrow, if no luck then its an engineering shop next week.

Assume the lower bolt isn’t really under too much stress when breaking so as long as its held pretty firm by a few mms worth of thread it should be okay?

Assume the lower bolt isn’t really under too much stress when breaking so as long as its held pretty firm by a few mms worth of thread it should be okay?

Its unlikely to fail catastrophically but I want everything on the braking system 100%. It it fails the calliper could come loose

I have a set of forks that were stripped and sent back by a customer that need to be sorted. A fresh bolt can be wound in and pulled out by hand if i try hard enough. Not good.
Local engineering place reckons around 20 quid to sort it.He seems happy enough with the amount of material around the hole to carry out the job. (its a skimpy round post mount,unlike a more beefier square shaped manitou)

Do as TJ says and get a helicoil or something similar.

Glue or threadlock is not an option!

as above – measure the hole depth and the length of screw that was in there and see if you have any thread to use – also do this to prevent you putting a screw in that is too long and splitting the fork leg.

If you still have some thread then I would be tempted to go the stud route with some epoxy (eg araldite) – drop the stud in, then put a bit off epoxy round it and then screw it in so you only get epoxy in the stripped bit. Then just use a nut to hold the brake on.

Or helicoil.