Shimano Ultegra Di2 11 speed - Disc brake failure

[Miles - Fourways]

Looking for help please, my Ultegra Di2 brakes keep going flat, fitted to a Trek project one bought in 2021, started after a flight with the bike, been redone and no problem with the last two flights. However it has become worse and only lasts around 100km before one brake lever will fail, it has been back to Trek multiple time, the Shimano agent in South Africa has had the bike for assessment and said the system is compromised with no explanation and no support, except buy the new 12 speed, (too expensive)

They also cannot say if the problem is the shifters or callipers!!

Apparently no spare parts are availably either.

I am thinking of replacing the shifters if I can find a set of R8070 Ultegra Di2 Shifters and maybe callipers as well. 

Advise or help would be much appreciated.

Thank you,

[BikeisLife]

I had an issue with these brakes from the clamp bolt on the STI. If you torqued the bolt to spec, it squashed the reservoir bladder and the brake wouldn't return nicely. Try loosen off the STI clamp bolt slightly and see if it helps.  

[Miles - Fourways]

8 minutes ago, BikeisLife said:

I had an issue with these brakes from the clamp bolt on the STI. If you torqued the bolt to spec, it squashed the reservoir bladder and the brake wouldn't return nicely. Try loosen off the STI clamp bolt slightly and see if it helps.  

Hi thank you, my problem is the pressure loss, it has been been done so many times but still loses pressure after a few rides, the levers return perfectly.

[RobertWhitehead]

Definitely a leak in the system if they've re-done the bleed multiple times. It can either be a hairline crack in the ceramic piston on the caliper side or a leaky seal inside the lever. 

[droo]

Before you go leak hunting, check that your caliper pistons are moving freely.

If it is a leak, spares can usually be found on SJS Cycles in the UK. Just look up the part numbers on Shimano's tech docs and use them as your search term.

 

[candyman]

On youtube I found a very helpful guy who specialises in all things Di2. He may have some videos relating to what you are experiencing, if not you can reach out to him via instagram. I have had issues with my shifter and he provided sound advice. The channel is called DI2_gp.