Campy H11 Bleed Problem

[wilwil]

I was thinking of selling my c64 rim brake bike and replacing with a campy hydro disc bike until I read this.

[roadchallenge]

So I have a small update on this.

I think it's indeed impossible to bleed the brakes using the Campy procedure. Every time I pump the brake lever while pulling the bottom syringe, the air bubbles appear in the bottom hose - I think the air might be coming through the master cylider bladder or the caliper o-ring.
However, I spent the whole evening, bleeding using procedures for Hope, Avid and Sram brakes, also unscrewing the caliper and gently tapping and rotating it to eliminate any trapped air. I think I made it to a point where there is no air in the system.

However, the pistons still move in a very uneven way - the one on the side whithout brake hose is much slower.
So I thought I'd take a look at the rear caliper, which was not touched by me at all since being bled by Campagnolo Pro Shop. And guess what - it is even worse. One piston almost does not advance, while the other one (the one on the side with hose) moves easily.

Of course I exercised the 'sticky' one multiple times, cleaned it thoroughly, lubricated with oil - no effect. Even removed the piston completely (by pumping it totally out of the caliper) to clean it. Still it does not move even closely to the other one.

I think I might start a separate topic on this, as quick googling shoeed it's not a Campagnolo-specific problem. However, I have to admit I'm already so tired of this, that I almost start to regret removing fully functional Ultegra Di2 and putting Campagnolo Record on this bike. It is definitely more beautiful, but the amount of troubles almost kill the joy.

Yeah video doesn't work... Man that sucks, thats my experience too, I don’t bother with lazy pistons though, I just hack them with paper trick, they move 0.6mm when pressurized anyway, so move fine after all setup, i’m 100% convinced air comes in at the shifter (not through o-ring at the port) but at the master cylinder inside, the only way to stop introducing is to not press shifter all the way and stop “pumping”, I just finish off by sucking and pulling until you don’t see any bubbles coming out., then close caliper port and see if shifter rock solid, if not then more sucking/pushing, takes me now 10-20 min for full re-bleed.

[roadchallenge]

I was thinking of selling my c64 rim brake bike and replacing with a campy hydro disc bike until I read this.

I would stick with di2, only get campy if you REALLY like it. I just can’t stand shimano/sram shifters. But campy disc brakes are the best feeling during the rides, hard to match.

I have to confess, I do ride rim brake SR on my road partially because of bleeding experience of csmpy on my cross bike.

[Calnago]

I suppose I might have to get me some Campy discs just cuz I hate not knowing what you guys are talking about. And, I REALLY like Campy. Lol.

[roadchallenge]

I suppose I might have to get me some Campy discs just cuz I hate not knowing what you guys are talking about. And, I REALLY like Campy. Lol.

Please do, maybe we will finally have proper campy bleed guide.

[c60rider]

The thing that frustrates me most is the campy guy on the tech video just looks so cool doing the installation and I just want to imagine I'm as slick as him. Reality soon hit.

[roadchallenge]

The thing that frustrates me most is the campy guy on the tech video just looks so cool doing the installation and I just want to imagine I'm as slick as him. Reality soon hit.

I loose my shit at the part where he squeezes lever then tightens the caliper as if there ever were any disc brake system that had equally traveling pistons to perfectly center caliper on the rotor (considering they also knew at the time their rotors out of true )

[Miller]

Got two bikes with campag discs and love them. Have had some minor issues with pad centering and shriekiness but the brakes are very controllable and powerful in use so I can forgive that.

[morrisond]

I was the one that started this topic and once I had the ever replaced it bled fine and no issues in a year since.

In fact - I ordered another H11 set last week for another bike.

They do feel incredible in use.

I just think thye might have had a bad batch of master cyclinders that allow air to enter the system.

Bike24 has B stock available which I would have to guess are levers that had bad master cyclinders and were sent back to Campy and redone with new ones.

[roadchallenge]

I was the one that started this topic and once I had the ever replaced it bled fine and no issues in a year since.

In fact - I ordered another H11 set last week for another bike.

They do feel incredible in use.

I just think thye might have had a bad batch of master cyclinders that allow air to enter the system.

Bike24 has B stock available which I would have to guess are levers that had bad master cyclinders and were sent back to Campy and redone with new ones.

Yeah I think I might have gotten bad cylinder batch, got mine as a very first batch from jbi, probably should get it warranted.

I absolutely love mine in use, only wish is shifter shape was same as rim brakes one.

[gorkypl]

I was the one that started this topic and once I had the ever replaced it bled fine and no issues in a year since.

So you can bleed now as indicated on the video and it does not suck air while pumping lever? That would be big news!

Could you check if the pistons move evenly now?

[graeme_f_k]

I got really frustrated with this issue affecting my rear caliper. On the very last part of flicking the brake lever and pulling fluid out of the caliper it would somehow suck air in from somewhere and the whole bleeding (literally!!) process would need doing again. I ended up just leaving this part off. I've wondered if the rear brake was a fraction spongy compared to the front but it brakes fine and no problems at all so I've just left it and kept a very close eye on it all. It's my first ever disc brake bike and I did a write up of all the problems with it but I'm extra cautious to watch the brakes as a result for now.

The rear brake is generally a little spongier than the front in almost any hydraulic brake system for bicycles for three reasons.

The first is that it's almost impossible in any hydraulic system to eliminate absolutely every small air bubble from the hose run, because small bubbles can and do adhere to the inner wall of the hose. The rear hose is longer than the front, so almost inevitably, tiny though they are, there will be more of these "micro-bubbles". Tapping the caliper, hose and lever with a soft impliment (rubber-handled screwdriver handle, say) and "rattling" the hoses can help with this.

Second, the hose is physically longer so there is more hose to flex and squirm as well as to expand slightly under pressure. That movement and expansion gives a small amount of "sponge" in the brake. As with a cable brake, run the shortest hose you can that gives a safe turning angle for the bars (I like to see 90-100 deg if there is no other limiter to bar movement) and doesn't result in a very tight bend on exit from the chainstay.

Third, the rear hose run is typically more horizontal and more complex than the front brake hose run, especially (as it tends to be in 99% of road bikes) if it's internal. It's harder to get a really good bleed. We advise shop techs to turn the bike rear-wheel-down in the workstand and to do a "pull" up from the lever end to use the tendency of bubbles to rise if they are struggling to get a good bleed. Also, to leave assembling the BB sleeve into the BB and assembling the cranks into the BB until after the initial bleed is completed - this removes a kink from the brake line and gives the straightest hose possible to make a good bleed a little easier.

[graeme_f_k]

Just read the c60rider thread. I had exact same issue, way I was able to solve it is:

pump lever full travel 2-3 times to push air from caliper, then stop pumping lever and only did push and pull for ~6 times, and all bubbles came out, then pressed lever 1/3 way (to prevent master cylinder piston seals from traveling too far ) and released rapidly to shake up bubbles in the lever. The way to check if system is bled properly, is to close the port at the caliper while bleed block is in, and press lever, if mushy then bleed was bad it should travel very little and be rock solid.

Also regarding rotors and brake pad rub:

1. rotors are both out of true for me.
2. Pistons are not balanced, so during initial pressing in one will touch rotor sooner than the other and cause rub, pistons are magnetic so they don’t balance well naturally, I just put piece of paper on one side between rotor and pad, the side is where piston touches rotor sooner than other, squeeze slowly until both pistons touch rotor and paper, then remove paper (or tape) and press firmly again and pistons should be equal distance from rotor (this trick fills caliper with equal fluids on each side). Even if caliper not perfectly centered to rotor, this will trick will make sure pads are centered properly. I use it all the time when I swap between wheels. One bas DT240 other White Industries CLD, so rear hub has 0.5mm rotor position difference. I can share pictures if anyone needs.

Hope this helps, I feel now like i got hang of the H11/magura system. And have no disc rub after long descends etc. Feel like i can use it on my next road bike.

If you use the oil level tool and you do a "pull" from the caliper end, to take air out and draw oil in from "higher up" the system, then a push, you shouldn't end up with dis-similar amounts of fluid L and R in the caliper. The oil level tool is centred in the caliper and following this procedure correctly will by place both pistons centred relative to the oil level tool.

[graeme_f_k]

I was thinking of selling my c64 rim brake bike and replacing with a campy hydro disc bike until I read this.

If you want discs, go for it.

As part of my work for Campag I have bled everything from development versions to scores of sets of production versions and if you use the tooling correctly and take a few precautions to get a good bleed (see my various notes on this thread) they are no more trouble to bleed than any other hydro brake and IMO an awful lot less hassle than some.

I know I am biased but virtually every gripe I have come across with the Campag system (and if I am honest, this is also true of the opposition which I do work on very regularly) is down to either frame preparation, an odd variation in assembly introduced by the installer or a bad installation. If the installation is correctly carried out with the right tools, it's actually (again, IMO) one of the most straightforward I have done - note: at Velotech, we teach / have taught & work on, admittedly some more regularly than others, Shimano, SRAM, Hayes, Clarks, Magura MTB and HS, Hope systems ...

[graeme_f_k]

3 things at play here:

1. Rubber seals on pistons that drag on caliper surface when they being pushed.
2. No way to regulate equal amount of fluid going on each side of piston to move them same distance.
3. Magnetic retraction of pistons.

Unless each piston is manufactured with perfect magnet weight/power and perfect rubber seal contact patch with caliper, there is no way to make sure by design that each poston travels exact amount during initial press, so you have to guide it a bit with tricks like paper etc. its been 1 year for me and it adjust for brake pad wear just fine. All it really does is to make sure there is just right amount oil on each side of piston inside caliper.

Nah, it does not work like this, unfortunately.
1. There is a drag, of course, but it is more or less even for both pistons. Or should be. Minor differences do not matter, as the pressure of hydraulic fluid is high.
2. This is not true. According to Pascal's law, if there is no air in the system, the pressure of fluid acting on both pistons is equal.
3. Magnetic forces are used only to hold the pads to the pistons. They have nothing to do with the retraction (this is done purely by seals).

I agree that it probably can work, but if there is a need for tricks to compensate uneven pad movement, then I'd say something is wrong with the system.

And these new pads look wonderful, but they were not included yet in April when I ordered 12s Record.

The springs are there because sometimes, the pads are not retained "hard" against the pistons by the magnets.

Typically this causes some small issues in a system which has become very hot, say from prolonged "drag" braking, where there is expansion in all the materials of the brake system itself - rotor, caliper and pads. Because the rollback is relatively small, if the pads are not retained tight to the piston, the heat is enough to close the clearances down to the point where you get occasional touch of the pads on the rotor even with the lever released. Most hydraulic disc brakes suffer from this to some extent. The springs are not there to compensate for uneven pad pressure. The sping is nothing like strong enough to force the pistons back against fluid pressure.

When your current pads wear, the new ones will almost certainly come, by default, with the new shape and the springs, there is a running change to this design in process now.