I got a Shimano 105 12 speed mechanical groupset from an LBS who's upgrading a new bike to Ultegra/Dura Ace for his client. My Vitus steel gravel frame was doing nothing and I decided to use it for more bike to work rides during winter. With fenders and a small rear rack attached it would make a perfect candidate.
So I went on and collected all stuff necessary with this brand new, unused groupset. I finished building the bike a few days ago but something is not right.
The left Shimano 105 ST-R7000 shifter is leaking oil. So I removed the brake line, cut off the part with the barb and re-attached a new barb and olive and connected the brake line again with the appropriate torque. Did a quick bleed to remove any possible air. Cleaned everything with alcohol.
Again, the shifter seems to leak oil. What could be the problem? Being new to Shimano hydraulic road brakes (rest of bikes using SRAM), the olive, is it identical on both ends? The oil seems to leak not from the lock nut but further towards the brake lever, at the end of the iron housing.
The right shifter is working fine, no visisble leakage there. I am using barbs/olives ordered on Alixpress.
by trickletracks
3 Comments
The bladder is probably leaking. You can buy replacement bladders but not official shimano ones AFAIK. I once replaced an entire shifter to resolve this properly
A few questions and observations for you:
Firstly there is a gap here which shows the nut isn’t installed all the way, there should be no gap.
Secondly you mention the leak is coming from closer towards to lever blade, there is a rubber gasket in the middle which Shimano calls the Diaphragm that if overtightened will fail causing it to leak, not to common but it does happen. It generally happens when lines are too full and the levers are pulled too hard. You can manually inspect it to see if it is split.
Here is the part number for the diaphragm, you can order just that part from shimano.
Y0C578000
[https://si.shimano.com/en/ev/ST-U6030-5092?q=st-r7120](https://si.shimano.com/en/ev/ST-U6030-5092?q=st-r7120)
Lastly, you didn’t mention which oil you used, I hope you used Mineral Oil as Dot fluid will eat the seals on Shimano brakes, rendering them unusable and the calipers and shifters will need to be replaced.
Hope that helps 🙂
https://preview.redd.it/pytpf6bsdz3g1.png?width=230&format=png&auto=webp&s=22e6535d48a578c07df89160b5ea1ceefa5b4ab9
I just had a look at the right shifter, the gap on the nut had my worries, it had the same gap. So I checked the torque on both shifters with my wrench on 6 Nm and I could wrench both nuts about a half turn! I know for sure that I had done this a few days back. Maybe it needed to settle? Maybe it was the angle between hoods and handle bar together with the gear cable which made it difficult to wrench. I moved both shifters on the handle bar to make it easier to wrench the nut.
I hope this was the cause of the leakage. 🤞