Help with dura ace rear mech.

[Billy Wizz]

i was about to to nip my cable up on the rear mech this morning, the slightest turn and it popped out on a spring now I can't get it back any ideas would be apprieciated, or is it another visit to the bike shop. ?

 

[boydj]

I'd break the chain and take the whole mech off so that I could get some leverage on that screw with no cable in there, to try to get it to catch.

 

[Billy Wizz]

I am starting to think its a heli coil in there and not a spring, cant find a lot of info its 10 years old will have a good look at the weekend.

 

[e-rider]

so when you try and tighten the cable down, the bolt pops out? Sounds like the thread has been stripped

 

[Billy Wizz]

I have pulled it out, I thought it was a spring but obviously it must be a helicoil, ? the thread has been stripped on the deraillier,

 

[Nibor]

That look like what remains of your threads.
If it is a helicoil you can always replace it.

 

[Globalti]

Where did you get the derailleur?

 

[Billy Wizz]

Its been on my bike since I bought it, its an old 7700 triple.

Why do you ask..?

 

[Svendo]

I've not had a 7700 RD, but none of the others I've had had a helicoil or anything in there. Have a look at the exploded techdoc thingy (PDF download) and there's not one on that. I think it must be as Nibor says, the thread from inside.

 

[Billy Wizz]

Svendo thanks for the download that is what I have been trawling the net for, I have been looking for the thread size of the bolt so I can order the helicoil.

At sometime in its life the thread has been stripped and someone has had the repair done which is the Helicoil, thanks to your pdf download I can now order a new helicoil and hopefully re insert.

 

[Svendo]

Aha! I thought a helicoil was a type of split helical washer. So I swap your what-a-helicoil-is for the location of shimano techdocs where everything they have is, including dealer manuals.