Bicycle Mechanics - Stripped Pinch Bolt Dura Ace RD

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hiker88
09-12-10, 05:34 PM
I was adjusting cable tension on the RD tonight. RD is 9 speed Dura Ace. When I went to put the bolt back in it acted as though it was stripped. I noticed a spring like object lying on the floor below the RD. The spring seems to wrap around the bolt and looks like a close fit, if I could get it to go back in the bolt hole.

Is the 'spring' I've found a replaceable part, or did I in fact strip somehting out from inside the RD body? The bolt itself looks ok.

Thanks for the help.

MudPie
09-12-10, 06:41 PM
The spiral winding is probably from the RD body. The bolt material is harder/stronger than the RD body.

I hope I am wrong, but there are typically no springs in/around the pinch bolt.
davidad
09-12-10, 06:46 PM
The spring goes between the adjusting screw and the threaded hole in the der body.

hiker88
09-12-10, 07:23 PM
I've been doing some research and I think the spring I found is actually something called a helicoil. It's used when you strip out a thread hole. I'm the second owner of the bike. I'm going to see about getting a new helicoil and the insertion tool and see if I can get it back how it was. The components are about 8 years old or so I think the previous owner might have stripped it out.
MudPie
09-12-10, 10:15 PM
The spring goes between the adjusting screw and the threaded hole in the der body.

I think the OP is referring to the cable pinch bolt, not the adjusting screw of the cable.
MudPie
09-12-10, 10:19 PM
Ah, yes, could be a thread repair coil (Helicoil is a trade name, others make it too).

Here's a source for everything you need, and includes installation instructions.

http://www.mcmaster.com/#threaded-inserts/=8tn2pk
hiker88
09-13-10, 01:14 PM
In case anyone else every gets in this situation you need a 5mm helicoil with a .80 pitch for the pinch bolt on a DA7700 RD. I got the kit for $25 at an automotive store and I'm going to give it a shot tonight.

The kit comes with a tap, an installation tool and about 10 helicoils. The instructions say to drill the hole out to a certain size, then use the tap to claen the threads and then to install the coil. A guy at the shop told me that since the RD had this all done once before, I should skip the drilling and just 'chase' the threads with the tap to make sure they are clean and then install the helicoil.

Wish me luck.
hiker88
09-13-10, 03:35 PM
THERE I FIXED IT!

Feeling less stressed now thanks. :)