Bicycle Mechanics - Can this broken Dura-Ace rear derailleur be repaired?
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So I have this old 9 speed Dura-Ace rear derailleur (RD-7700). That piece around the pivot bolt with the little screw on it has broken (please see the picture).
I know this comes apart. Is there anywhere I can buy a replacement piece? Or any other suggestions for fixing this?
A lot of LBS have bins of broken/used parts just for situations such as yours. If you have an indy near you (not a chain) I suggest you take it down to them and see if they can help.
08-14-09, 07:42 PM
if you can find that part you may be able to fix it but it is not an easy task. that spring has alot of tension.
08-14-09, 07:50 PM
I brought a vintage LX rear derailer with the same problem to my LBS. This derailer was a date correct rear DR for a vintage MTB I was building so I really wanted to repair it. Verdict: Yes it can be repaired, but no, it's not worth the cost.
08-15-09, 07:38 AM
prof2k what is the condition of the pulleys? I have an 8spd DA but the pulleys are shot. I just want to use it for chain tension on Internal 8 so I think those would work. if you care to part with them.
08-15-09, 08:04 AM
I don't know where you can buy the part but to remove it, you must first rotate the c-clip (more like a "u") using a small screw driver then pry it off the threaded shaft. This will release the broken part you seek to replace along with a torsion spring. Reinstallation requires retensioning the spring while at the same time reinserting the c-clip. It takes a bit of dexterity to do so and a second set of hands can be useful.
If you could remove the piece and post a picture I could see if it matches the same part on a broken Deore derailler that I have. I doubt it but you never know. Failing it, scour Ebay or post in the wanted section for a broken (just not in the same place) Dura Ace 7700 derailler. Someone must have one. If you can't find the part, send it to me and I'll continue the search :)
what is the condition of the pulleys?
The pulleys are in great shape. The derailleur only had a few hundred miles on it before a crash where the derailleur hanger broke off and did this to the derailleur. The pulleys on this derailleur are different sized than ones on a dura-ace 8 speed; I don't know if that matters. However, I'm not quite ready to part with this, I want to try and find another broken derailleur to salvage the parts from. If I change my mind though I will let you know.
I took apart a few derailleurs from my broken parts bin, but none of them would work. One from an 8 speed XT derailleur (RD-M739) looked like it was going to work, but the size is just a little bit different. I also took apart a 7-speed shimano 600 (rd-6400) derailleur for fun, but it was nowhere close.
I think one from a 9-speed ultegra or 105 derailleur will also work, so I'm looking out for any of those in broken condition.
From left to right here is the one from the dura-ace RD, the XT, and then the shimano 600.
I found what I'm looking for. I can a whole new B-axle assembly for around $20. That includes the part I need :crash:
08-16-09, 08:58 PM
Where did you find the parts?
This is a place that sells them:
However, I'm going to see if any bike shops in my area can order the parts for me now that I know shimano sells them.
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