Got this used di2 equipped bike with what seemed to be just a spongy front brake. Bleeding as per manual. Still "mushy". Emptied the line and disconnected the hose. The lever just don't return all the way back on its own. Removed the lever from the bars and can't see any obvious problems. It just moves half way back after being pressed normally and slows down in the second half of the travel. Then stops at about 1mm from the proper position. And I can push it to return. Pressing it quickly a few times makes it snappy again for a few returns and then it slows again.

My guesses went from cylinder, to dirt, to di2 cable stuck between the springs or the springs mounted incorrectly but just impossible to understand what's going on inside without removing the lever. And I'd rather not just dump a degreaser or wd-40 into a di2 brifter...

Any clues or similar experiences?

Update: took it to another LBS and the owner said he has "a friend that works for Shimano" so I left it there ATM for the "friend" to check.

  • 2
    Wd40 won't affect electrical componets. It's used for displacing water often to get electrics functional. Hence W.D.
    – Noise
    Commented Apr 6, 2021 at 16:57
  • 1
    It's doing its slowing down in the second half of the travel even with the hose disconnected? Any change with the bleed port open? (Note that if both of those things are true at once, all the fluid will come out.) Commented Apr 8, 2021 at 4:45
  • It is doing it with the hose detached and off the bars @NathanKnutson Commented Apr 9, 2021 at 6:09

3 Answers 3


I had a similar issue with the right lever on a customer's bike after installing some new handlebars.

I found the issue to be the bolt for the handlebar clamp was too tight; I backed off the 5mm bolt and the lever popped out to its normal position.

I assume the plastic body of the lever gets deformed if the bolt is too tight and the piston runs the full length of the body.


So the part is more than 2 years old and not covered by the warranty. But an LBS took them to "a friend that works for shimano" who "changed the gaskets" (cit. from italian) which I suppose is the seals of the piston in the brifter that got damaged or displaced somehow. A pity can't know for sure what it was but visually there are no changes in the springs and di2 cable routing.

After the first 100km feels like new.


The range of travel where it's having trouble sounds an awful lot like the same range of travel that makes up the difference between the minimum and maximum free stroke setting. I haven't seen this issue and my understanding of how the free stroke mechanism on these works isn't perfect, but the first thing I would look at is whether the free stroke hardware seems to be in order and how it responds to that adjustment.

enter image description here

  • The servowave mechanism might be clogged too. It's crazy how much stuff the engineers can pack into a brifter.
    – MaplePanda
    Commented Apr 8, 2021 at 5:30
  • For what it worth I've tried to move both adjustments screwws full in and full out and didn't notice any difference in the behavior. Commented Apr 9, 2021 at 6:13

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.