[thomas_r]

Dear road.cc community,

I recently bought a Simplon Pride 1 roadbike with a Shimano Dura-Ace 11-speed Di2 groupset with disc brakes.

At first, after I moved the right STI-9170 Dura-Ace 11-speed brake lever slightly higher, I suddenly had a spongy bite point, meaning play at the brake lever and reduced braking power on the rear brake.
On the left brake lever, by the way, moving it higher did not cause any problems; the brake pressure and braking power remain fully present.

After buying the Shimano bleeding kit and the correct oil for refilling, reading the Shimano dealer manual (DM-R9150-09, page 103 ff.), and watching several YouTube videos, including “GCN – Bleeding Shimano Disc Brakes” and “Tour – Bleeding Road Bike Disc Brakes”, I unfortunately had no success bleeding the brake yesterday, 13/07/2026. I now have zero braking power, meaning the lever cannot brake the rear wheel at all. So I would like to ask you for advice.

Here are the steps I followed:

1. First, I tried bleeding only from the top at the lever:

I clamped the road bike into a repair stand and removed both wheels.

I removed the handlebar tape, loosened the brake lever, and positioned it horizontally. In my case, that meant rotating it downwards so that the bleed screw on the STI lever was horizontal to the floor.

I screwed the funnel with the adapter into the brake lever and filled it with fresh oil.

I dismounted the rear brake caliper from the bike frame, removed the brake pads, inserted the yellow spacer (Shimano bleed block), and moved the caliper down at the lowest point.

I actuated the brake lever several times and let it snap back. A wonderfully firm pressure built up, and at that point everything seemed fine.

Then I removed all the bleeding tools and reassembled the components.

As soon as the brake lever was back in its old position, meaning higher than horizontal, there was again a lot of play at the lever, and the braking effect was even slightly worse than before.

2. Then I tried filling from below at the caliper upwards to the lever:

Everything was set up as before, but this time I connected the oil syringe from below to the bleed nipple on the caliper and screwed the empty funnel onto the brake lever at the top. The funnel was in vertical position.

Now the crucial point: no matter whether I opened the bleed nipple (with the filled syringe attached) using a 7 mm ring spanner by 1/8 turn, 1/4 turn, or even much more, I could not push any oil into the line in order to fill the oil funnel from bottom to top via the oil system.

It seemed to me as if there was some kind of blockage in the system, for example a kinked brake hose, the bleed nipple not opening, or as if there were some kind of shut-off valve before the funnel or inside the brake lever.

In summary: if you could please explain why I was unable to refill oil from below, I would probably be a big step closer to solving the problem.

Many thanks for your advice.

Best regards,
Thomas

Topic

[thomas_r]

Hi tomlew, I found the issue and it was a stuck hydraulic cylinder inside the lever due to the excessive torque I applied to fix the lever onto the handlebar, though based on my previous experience with “conventional” levers for rim brakes.
The Shimano 9170 lever casing seems to twist (deform) slightly under such high screw torque and hence the hydraulic cylinder cannot move in and out (forward and backward) freely any more. Fortunately, the deformation of the lever casing does not seem to be permanent. I’ll try to upload videos showing the situation before and after on the right lever (rear brake) as well as the situation at the left lever (front brake), which surpsisingly despite the same high torque applied to mount the lever onto the handlebar, apparently never showed such deformation, which is why I did not suspect this to be the root cause in the first place.

Attachments:

1. 2026-07-18_Right-lever-9170-stuck.mp4

[tomlew]

Oh, one more thing.

As the lever is removed frmo the handlebar, make sure that internal routing is unbostructed. Try pulling the hose gently 10 cm each way (first towards the caliper and then back). The hose should have freedom to move inside the frame to acommodate turning the handlebar.

[tomlew]

Hi Thomas,

Clearly the problem is related to moving the lever. In a closed hydraulic system that should not cause any problems, as the hose moves together with the lever and the pressure inside the hose should remain constant.

A sudden change in brake feel suggests that some oil has leaked out of the system.

As the hose is very, very unlikely to rupture along its length (unless it’s badly worn or damaged), the most likely location of the leak is the hose-lever connection.

My first suggestion would be to check whether the hose is securely attached to the lever. Remove the STI from the handlebar and check for any oil underneath.

As the system is leaking anyway, try removing the hose entirely and check whether it is cut exactly square/perpendicular and there is no damage along its length and the walls are smooth (as in: no marks of having been broken inwards).

Replace the olive and insert (you may need to shorten the hose by 1-2 cm, but that’s not a big deal) and try to refill the hose with oil while the lever end is free – the oil should leak out profusely, which will show you clearly whether the hose is clear or maybe there’s some kind of obstruction.

Then attach the hose to the lever and try to refill&bleed the system again (with the open bleed port, obviously).

Also, while reassembling the lever make sure that the hose has freedom to move against the handlebar as you move the lever up and down. Possibly it was somehow restricted (by bar tape maybe? Or by hose ports, if the handlebar provides internal hose routing).

Let me know how it went!

[Author]

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