Idea's for bike repair?

[Thaumaturge]

I'm stripping a suspension frame for respray and have run into the following problem. The seatstays pivot connection to the chainstays have a steel spring inside the holes to accomodate the bolt thread but one has come out and does not want to go back in. I tried threading it onto the bolt and tapping in but it wasnt keen, and cant seem to manually thread tthe spring back in on its own. Anyone else done this/have idea's? Don't want to tap the hole as will be too weak a thread. Pics below..

 

[My_Teenage_Self]

Looks like a helicoil.

Buy a new helicoil and it should thread straight in.

 

[Thaumaturge]

Re:

Really? That's awesome.. i'll see about getting a new one .. thanks

 

[focomat 1c]

Re:

Ideally you need to clean up the existing thread in the aluminium before inserting the new helicoil , it looks damaged .
However the helicoil tap you would need could be expensive . Your option is to buy a pack of helicoils from Screwfix ( check the size of the
pivot bolt ) and try to insert one into the existing thread . You will need an inserting tool in order to do this correctly , but you could
make one by cutting a slot into the end of a small rod . Once the helicoil is fully inserted you have to break off the tang on the end of the
insert before you can use it

Have a look at the helicoil repair kits which include all the items required as mentioned above , it may be that some loctite could
be beneficial to help secure the new helicoil in place ?

If you have any motor engineers ( people who rebuild/recondition engine cylinder heads etc ) in your area it would be worth a phone call ,
they would frequently use helicoil inserts in their repairs , and could be the easiest/cheapest option

 

[Thaumaturge]

Thanks.. i was looking at some cheap helicoil kits on ebay which have all the bits you need and will prob grab one for future use. The loctite is a good shout as it shouldn't have unscrewed so easily anyway. Haven't heard of these fittings before so i've learnt something. Seem very handy..

 

[Timoth27]

Re:

All I will say is you get what you pay for and the last thing you want is to have problems once the new helicoil is part way in. My advice would be try and buy a proper “helicoil” kit, yes they are more expensive but still cheaper than trashing your frame.

 

[Graham_hkr]

Re: Re:

If you have any motor engineers ( people who rebuild/recondition engine cylinder heads etc ) in your area it would be worth a phone call ,
they would frequently use helicoil inserts in their repairs , and could be the easiest/cheapest option

I'd take this advice tbh.
As stated you need to buy a decent Helicoil kit & not likely to use it again, a local engineering shop or motor engineers will probably sort you out for a couple quid, well maybe a tad more but a lot less than a decent kit!

 

[fettler]

Re:

If the helicoil came out readily it might have been poorly fitted or the surrounding aluminium has become damaged. You may need to go up a thread size, sleeve or shim etc. Might be worth measuring the remaining bore size against helicoils recommended sizes before buying stuff that might fall out again.

 

[Peachy!]

Graham, if you struggle to find someone local, I’ve got a descent kit at work in Elvington.

Edit: oops! ignore me, I got mixed up with who needed help :facepalm:

 

[Thaumaturge]

I don't think the existing thread is damaged so hopefully the new coil will screw in easily enough. The kits on ebay are only circa £6 with more coils than i need and will be good enough i think. I'll update here so you can all say i told you so if it all goes pete tong!