Shimano Ultegra Di2 Issue

Addictedtocarbon1

Hello,

I was washing my Cervelo yesterday and after I had finished I realised the battery was not in. After this, without remembering that the battery holder was wet, I secured the battery in place.
When trying to change the gears up and down on the cassette with the rear derailleur I noticed it would not change gear, however the front derailleur works. I presumed that it had been water damaged so I removed the battery, used a hairdryer on the battery holding unit, dried the battery and the unit, then charged the battery again.
This morning after repeating the same process the rear shifting still does not work. After several attempts, there is still no response.
Moreover I do not know where exactly the water damage has affected the group set. Would the water have caused the wiring to become faulty, the battery unit and/or the battery to become faulty?


Any help would be great! Cheers.

DHA987S

If the front works then the system is fine. I suspect it might be a loose cable to the rear mech that is the issue. They are pretty tight if you use the cable installer to put them in, there is an audible click, but if you do it by hand you won't get it fully seated and tight.

eddiefiola

yeah, my rear derallieur problem was a loose cable, it feels clicked in but isnt necessarily making good contact.

meanredspider

And remember - it can be the cable either at the shifter, the junction or the RD not just at the RD. I have a couple of Ultegra Di2 bikes (one is nearly 2 years old) and I've not had a moment's issue with the system.

I don't know if this will work, but one way of checking is to do the battery check using the rear shifter (hold across). If the battery check light comes on you can be reasonably sure that it's the RD cable.