I recently rebuilt the rear shifter on my Campy Record 10-sp, including replacing the thumb button return spring, the finger shift lever return spring, the G-springs and their carrier, and the index gear. After a few hundred break-in miles, it shifted slicker than owl snot for about a month. Then it began being fussy about down-shifts, shifts to the larger cogs, most commonly when it was at the extreme end of the cluster (12/11-t). It felt as if the finger shift lever wasn't engaging the detents, but I could wiggle the lever or push it inboard at different angles other than the usual perpendicular, and sometimes push it outboard, and usually I could get it to resume engaging and down-shifting.
I thought to remove the shifter body from the handlebar to troubleshoot the problem but when I removed the shifter cable (which was a new OE Campy cable when installed six months ago), I found one strand in the shifter cable had snapped inside the shifter body, near the cable nipple. Because that unwinding wire would have coiled and gathered up inside the shifter body, possibly bunching up to resist the cable being pulled, I concluded that that likely was the problem. So I reinstalled the most recent old cable, which was still serviceable and only replaced on general principles.
Except that didn't fix anything. The finger shift lever still swings like it isn't engaging the the index gear. With the bike on a work stand I'm basically wiggling the lever in every direction trying to effect some sort of change, or feel something that will help me diagnose the cause. It sometimes clicks when I push the lever outboard, which sometimes but not always is an indication that it will "catch" when pushed in the proper (inboard) direction. Otherwise, I am baffled.
So now I figure the next step is to disassemble the shifter to see if I can determine what's gone wrong. But before I do that, I wanted to front-load my search by posting here to ask for suggestions what to look for. I rebuilt an 8-sp Ergo shifter some years ago but this was my first attempt rebuilding the 10-sp, so I don't have a lot of experience at this.
TIA for your help.
I thought to remove the shifter body from the handlebar to troubleshoot the problem but when I removed the shifter cable (which was a new OE Campy cable when installed six months ago), I found one strand in the shifter cable had snapped inside the shifter body, near the cable nipple. Because that unwinding wire would have coiled and gathered up inside the shifter body, possibly bunching up to resist the cable being pulled, I concluded that that likely was the problem. So I reinstalled the most recent old cable, which was still serviceable and only replaced on general principles.
Except that didn't fix anything. The finger shift lever still swings like it isn't engaging the the index gear. With the bike on a work stand I'm basically wiggling the lever in every direction trying to effect some sort of change, or feel something that will help me diagnose the cause. It sometimes clicks when I push the lever outboard, which sometimes but not always is an indication that it will "catch" when pushed in the proper (inboard) direction. Otherwise, I am baffled.
So now I figure the next step is to disassemble the shifter to see if I can determine what's gone wrong. But before I do that, I wanted to front-load my search by posting here to ask for suggestions what to look for. I rebuilt an 8-sp Ergo shifter some years ago but this was my first attempt rebuilding the 10-sp, so I don't have a lot of experience at this.
TIA for your help.