Fixing a Cracked Chorus Rear Der?
 

My Chorus rear der is starting to crack. I think it's a pre-2001 9 speed which means that my Ergo shifters won't work with the current Campy 9 speed. While I'm figuring out whether to upgrade to current 9 or 10 speed, look for a pre-2001 9 speed rear der, or go w/ D/A, does anyone have any ideas on making a temporary fix? Is there any kind of adhesive I could fill the crack with as a temporary solution?

I thought one of the beauties of Campag, was that you could buy spare parts from them and make a repair. So order the replacement part. While you wait for it to come, I would suggest binding the boss with steel wire embedded in epoxy. This wouldnt be pretty but should prevent catastrophic failure when you are miles from home. Also check the crack before every ride for any sudden increase in length.

You could also drill a small hole at the very end of the crack. This will stop the crack from propagating.

Possible Fix: Do as the previous person replied and drill a very small hole in the case to stop the crack from spreading. Remove the pivot bolt and check to see if it has gone completely through. If not and you feel like keeping it around for a while longer use a V-shaped file and file the crack out. Then (if you can find them) use a special aluminun repair welding rod (usually can find them at auto or boat shows. Seller welds coke cans together with hand held bottle torch for demonstration) Fill grove with welding rod and file smooth.

Reality Fix: Avoid all the trouble of time consuming work of repairing as mentioned above and see if you can purchase this part. You could even step down to another level of Campy 9-speed derailleur. There should be no issue since it's the shifter that has the indexed points and not the derailleur. The derailleur is just spring loaded and does what the shifter tells it to. I'm sure the replacement part is not cheap and if your part is 3+ years old I would just change it due to that.

As for those alum rods. I used them on a 1968 Johnson outboard motor to weld 3 complete breaks in a bracket that held a belt driven generator for battery charging. Not only did it hold, it lasted me 3 years and the guy I sold the boat to 2 years ago said it's still holding. Hey, it's worth a try.

Good Luck!