Di2 FD problem

[havana]

My Di2 FD (Ultegra, braze on) sometimes slides when shifting. It happens about once every other ride. I have to stop, reposition the derailleur en tighten the bolt again. Very annoying !

Tried so far

- tightening the bolt
- installing the silver plate + rotation bolt for extra support

Is there something else I can try? Loctite maybe?

[mattr]

Is the bolt bottoming out? SO you are only tightening against the mech, instead of clamping the bracket. A washer might help.

Try degreasing the whole area and adding some fibre grip.

Isn't the silver plate and rotation bolt sort of compulsory anyway?

[havana]

Thanks for that.

Wil try finish line paste + loctite.

Don't think the bolt is bottoming out.

Not sure whether the plate + bolt are mandatory. Figured I would first try without, probably not a good idea. I never read manuals, so I didn't really get the point when I installed the FD initially.

[BdaGhisallo]

The plate and the tightening of the support bolt are mandatory.

[goodboyr]

So is reading the manuals.

Sent from my SM-G900W8 using Tapatalk

[wheelsONfire]

Do you use the small screw that "locks" the FD (in angle) towards the chainrings?
Loctite 222 small is enough to void bolt from vibrating loose.
222 holds enough, it is considered small for bonding properties which is the lightest of Loctite.
I used it for motorcycles to, so it is sufficent for a bike.

If it's not that, it seems the seat mast tube of the frame is deforming just tiny so FD moves loose.
Or is it that the Braze-on don't stay fixed, even though torqued at the painted surface?

[havana]

Re-installed the FD with loctite, carbon paste and off course the plate + screw.

I've also put some extra tension on the screws holding the braze on.