Campy H11 Bleed Problem

Discuss light weight issues concerning road bikes & parts.
morrisond
Posts: 991
Joined: Thu Mar 25, 2004 8:34 pm

by morrisond

Has anyone else seen this?

I got the Rear Brake to bleed no problem (using the Campagnolo Bleed Kit and oil level tool) and it's working great. It was very quick.

However I'm trying to bleed the Front Brake (left lever which activates the front Derailleur). I have tried 5x now.

Air keeps entering the system once I started squeezing the brake lever. Before that I got all the air out.

When I push fluid from Caliper I can hear air in the Lever body and fluid is leaking onto the brake lever. It is not leaking out of the bleed port where the top Syringe is threaded in.

I believe there is a leak in the Master Cyclinder.

Does this make sense?

by Weenie


roadchallenge
Posts: 151
Joined: Mon Dec 05, 2016 5:13 am

by roadchallenge

Yeah have this on both, I think its air trapped in cylinder? And hissing i suspect is air enetring back into cylinder, trying to figure out right now what to do sbout it.

morrisond
Posts: 991
Joined: Thu Mar 25, 2004 8:34 pm

by morrisond

I ended up having to send the lever back and get a replacement. I think it was just a bad master cylinder from the factory - but they couldn't just send me a new cylinder as the parts weren't available yet. The Master Cylinders are really easy to replace if it's an issue in the future.

It works great now and I love the brakes - Best Hydro's on the market by far.

roadchallenge
Posts: 151
Joined: Mon Dec 05, 2016 5:13 am

by roadchallenge

Strange, I have same hissing at brake lever on both levers when I push from caliper! I was just thinking the air is trapped in master cylinder, and every time I pump lever it would get portion of that trapped air into the line, and then if I push back from caliper it just pumps that air back into master cylinder. If I slowly push and suck then there is no air bubbles coming out. Maybe I should just send both, although I ended up giving up at some point and just riding them (except pad on inner side of caliper not retracting fast enough after prolonged braking) everything was just fine.

Did you warrant it with Campy North America ?

gorkypl
Posts: 158
Joined: Fri Sep 21, 2018 9:31 am
Location: Poland

by gorkypl

Hi guys, how have it ended?
I tried bleeding the brakes today after other options of dealing with one piston being "lazy" failed, and have exact the same symptom, ie during the last phase of bleeding, when I start pumping with brake lever, there is always a lot of air in the hose.
Cannot say I have any evident symptoms like oil leak from master cylinder, though.

c60rider
Posts: 616
Joined: Mon Feb 27, 2017 11:12 pm

by c60rider

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.

roadchallenge
Posts: 151
Joined: Mon Dec 05, 2016 5:13 am

by roadchallenge

I think when you pump lever it pumps air into system, by design ...

What campy doesn't tell is following:

1) pump lever while sucking from caliper side to get trapped air out of caliper. But at the same time you will introduce air at the shifter, as long as you don’t pump that new air all the way to caliper, it will easily come out at shifter and then later on at caliper side as-well )

2) basically after you made sure nothing trapped in caliper you will end up with some air in the line and shifter, I guess thats normal Magura behavior.

3) After pumping shifter and sucking from caliper, I basically just pushed and pulled 4-5 times until no air coming out. And closed the system. So far works perfectly fine! And they are rock stiff not mishy.

c60rider
Posts: 616
Joined: Mon Feb 27, 2017 11:12 pm

by c60rider

roadchallenge wrote:
Fri Aug 16, 2019 1:03 am
I think when you pump lever it pumps air into system, by design ...

What campy doesn't tell is following:

1) pump lever while sucking from caliper side to get trapped air out of caliper. But at the same time you will introduce air at the shifter, as long as you don’t pump that new air all the way to caliper, it will easily come out at shifter and then later on at caliper side as-well )

2) basically after you made sure nothing trapped in caliper you will end up with some air in the line and shifter, I guess thats normal Magura behavior.

3) After pumping shifter and sucking from caliper, I basically just pushed and pulled 4-5 times until no air coming out. And closed the system. So far works perfectly fine! And they are rock stiff not mishy.
Thanks for confirming this as part 3 is what I did eventually but I haven't used them enough to get confidence as it's my winter bike to be.

gorkypl
Posts: 158
Joined: Fri Sep 21, 2018 9:31 am
Location: Poland

by gorkypl

I am actually starting to believe that there might be air trapped somewhere in the caliper - a bigger bubble that is not able to escape easily. In few days I will try bleeding again while holding caliper in hand, rotating it, and see if it helps.
In the meantime it would be nice to have an input from someone like gfk - maybe it is a known issue (like master cylinder being faulty or sth).

The system is airtight by deisgn, so it certainly cannot pump air while pressing the lever, unless it's faulty.

roadchallenge
Posts: 151
Joined: Mon Dec 05, 2016 5:13 am

by roadchallenge

gorkypl wrote:
Fri Aug 16, 2019 4:52 pm
I am actually starting to believe that there might be air trapped somewhere in the caliper - a bigger bubble that is not able to escape easily. In few days I will try bleeding again while holding caliper in hand, rotating it, and see if it helps.
In the meantime it would be nice to have an input from someone like gfk - maybe it is a known issue (like master cylinder being faulty or sth).

The system is airtight by deisgn, so it certainly cannot pump air while pressing the lever, unless it's faulty.
Unless its leaking somewhere else than ports, I would say its not faulty.
System is airtight but by use of rubber seals, they are at both ends, caliper and shifter, so I think when you squeeze lever all the way without system being closed its quite well can push seal too far and gulp air.

gorkypl
Posts: 158
Joined: Fri Sep 21, 2018 9:31 am
Location: Poland

by gorkypl

c60rider wrote:
Thu Aug 15, 2019 11:42 pm
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.
I have read your thread thoroughly and have similar view on many things. However, I do find disc brakes useful in less than optimal conditions, so I'd rather learn to live with them than abandon totally. And I cannot imagine living without disc brakes in a gravel bike, which gets ridden even more often than the road one.

Back to the topic - I would say it's highly impossible that the air is being sucked via the top port. The bottom one gives me less confidence, as it works in a more mysterious way, but I doubt the air will be sucked into the system without the oil coming out from it when the syringe is pushed in the other direction.

I'll try bleeding again today, this time rotating the caliper... Hoping for @graeme_f_k to provide some info if possible, too.

roadchallenge
Posts: 151
Joined: Mon Dec 05, 2016 5:13 am

by roadchallenge

Haven’t read your thread through, but looks good.

What is the issue you having bu the way? What made you think you have air trapped?

P.S. I only have my campy hydro on cx bike (which turns out is a gravel bike because its has 40mm rubber on it... ;) ) for road I have direct mounts, and I just hold on for dear life when it rains, but then enjoy the lower weight and ease of traditional rim brake :D

gorkypl
Posts: 158
Joined: Fri Sep 21, 2018 9:31 am
Location: Poland

by gorkypl

I have exact the same issue as the author of the first message in the thread and c60rider who posted in this thread too. The air is showing in the system during the last phase of bleeding procedure.

roadchallenge
Posts: 151
Joined: Mon Dec 05, 2016 5:13 am

by roadchallenge

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.

roadchallenge
Posts: 151
Joined: Mon Dec 05, 2016 5:13 am

by roadchallenge

gorkypl wrote:
Mon Aug 19, 2019 5:43 pm
I have exact the same issue as the author of the first message in the thread and c60rider who posted in this thread too. The air is showing in the system during the last phase of bleeding procedure.
Ouch, does it leak at master cylinder aswell?

by Weenie


Post Reply