edopizza

Hello

I have a triple STI shifting lever that suddenly stopped to shift down. If the tension on the cable is released, the shift down lever pop the mechanisms all the way down, without stopping at the third "half down" or the second position.
The left shift down lever seems to have a lot more back and forward movement freedom then the right one.
I am wondering if tightening a little bit the nut on the main rotation axle, which is secured with a melted plastic seal, will fix the problem.
Anybody already tried it?

The hints in this old tread didn't solved the problem:
https://www.bikeforums.net/archive/in.../t-447439.html

Many thanks for your help!

ItchyZipper

Hello: In my experience, it is a "dirty shifter". It's not actually dirt, but the grease inside the shifter has hardened and changed into somthing more like earwax than grease. Cleaning the shifter is pretty easy and will fix this most of the time. I use this technique...I use a spray degeaser, I forget the name now, but it is a common solvent based degreaser we use in the shop. That will start to melt the grease and get it to be more like it's old self. Spray it in there good and keep operating the shifter. I'll do that a couple of times, waiting a short bit between apps. Then blow the shifter out, with compressed air. The shifter is probally working now. Repeat this process with WD-40 as the solvent. Finally I spray in a light penetrating lube, not an oil type, but a dry lube. And you're done. Hope that helps.

Kimmo

It may help if you give us the model and perhaps year of your kit; this sounds a bit different to the usual symptoms of gumming up... and some kinds of STI lever are prone to failure by breakage, IIRC.

If it's recent 105 you may be in trouble.

Al1943

Shoot it full of WD 40. If that doesn't fix it replace the shift cables and cable housings.

badamsjr

After getting it clean, I use Triflow, as it seems to have less of a problem with buildup over numerous applications compared to dry lube.

TromboneAl

I've had and solved exactly this problem with two sets of STI shifters. I actually got this bike for only $65 at a garage sale, in part because the shifters were completely non-functional due to this problem.

ItchyZipper's solution will work like a charm. The problem will probably come back now and then, but you can just repeat the WD40 application.