Shimano R785 lever developed a leak

Lewis Moon · #1 10-21-2023, 06:52 PM

My Shimano R785 Ultegra right lever started getting mushy so I peeled back the hood and found that the reservoir cap was leaking. Not to be confused with the upper bleed screw. It's the diamond shaped plate on top with two screws. I read where this was not repairable...any suggestions? If I need new levers, which are compatible with R785 wiring bumped up from 10 to 11 speeds?

oldpotatoe · #2 10-22-2023, 06:02 AM

Quote:

Originally Posted by Lewis Moon

My Shimano R785 Ultegra right lever started getting mushy so I peeled back the hood and found that the reservoir cap was leaking. Not to be confused with the upper bleed screw. It's the diamond shaped plate on top with two screws. I read where this was not repairable...any suggestions? If I need new levers, which are compatible with R785 wiring bumped up from 10 to 11 speeds?

Is it the cap? Or seal? Does it have a SKU/part number?

Lewis Moon · #3 10-22-2023, 07:53 AM

Quote:

Originally Posted by oldpotatoe

Is it the cap? Or seal? Does it have a SKU/part number?

Because it was obviously leaking I pulled it off (if I remember correctly Shimano cautions against this) and both seem intact, so I flipped the seal over (it's flat on both sides). I'll refill it and see if it holds. Otherwise, from the schematics I've seen, neither has a part number.
Really not looking forward to spending ~$200 on a new lever.

batman1425 · #4 10-22-2023, 08:22 AM

Totally not recommended but if this was my bike and flipping the seal didn't work, I might try a carefully applied bead of RTV on top of/next to the seal, seeing if that seals, and then keeping a close eye on it. I wouldn't consider that to be a long term solution and I'd actively avoid any high speed descents but it might buy you some time, depending on your use case, while searching for a deal on a replacement.

Lewis Moon · #5 10-22-2023, 01:05 PM

Welp...I bled the brake then took it out for a ride and....it still leaks a bit. From what I've read this type of leak, while not "common", happens more than it should. Looks like Shimano changed the design in later models.
On the up side, I swapped in a set of Hope floating rotors and.... HOLY 5#!+!!!!! I almost went over the handlebars! I'm using Jagwire organic pads and boy does that combo stop!
Can anyone suggest a Di2 compatibility chart? I'm thinking I won't get the same levers.

tellyho · #6 10-22-2023, 02:25 PM

I'd definitely go for the RTV solution. Nothing to lose.

caneye · #7 10-22-2023, 08:23 PM

I've got the same shifter and have noticed similar leak from the plate.

I'll be keen to apply the RTV solution. But I imagine the surface has to be absolutely clean and dry, for RTV to be effective.

What purpose does this "plate" serves?

gavingould · #8 10-25-2023, 07:40 PM

I’ve had two R785 levers develop leaks from cracks in the lever bodies.
Ultegra r8070 levers weren’t available at the time so I went with GRX rx815.
All are 11spd.