Amazing problems with Magura Louise BAT Carbon
I recently bought a pair of 08 Louise BAT Carbon disc brakes 180/160. I have had several problems with them and need all the help I can get. You should know that hose shortening, installation and bleeding were not done by me but from good bike technicians. The bike is a Giant Trance with a Fox fork (IS mounts).
First of all, after hose shortening and fitting by the LBS guys, I tried pulling the levers. The BAT adjuster was screwed in and the levers were as far away from the bar as possible.
Everything seemed fine for the first 5-6 pumps, but afterwards I could pull the levers all the way to the bars without any braking power. The explanation I got from the bike shop is that somehow the oil can't get back to the cylinder. They emptied and re-bled the brake, checking for air etc. and the result was exactly the same: First 5-6 pumps ok, then the lever went all the way to the bars. They said that it was certainly a defective brake and that I should contact Magura.
I took the brakes to a different bike shop, who managed to fix that problem, if I am not mistaken, by bleeding the brakes the other way aorund or something like that. I thought the problem was fixed, until I hit the trails. By the way, the guys there told me that mineral oil has a different, more progressive feel than DOT (my old brakes were Hayes HFX-9) and that it is the mineral oil that is causing this 'softness'.
Although the original problem has been solved:
- I can't lock the wheels with one finger (I could do that with the old brakes)
- Braking power is nowhere near as good as the old brakes
- There is an amazing noise I can't get rid of both front and rear (I'm starting to think that somehow the pads were contaminated during the bleeding).
- The BAT is totally useless as it has to be screwed in all the time for the brakes to work.
Oh, and by the way, although my fingers are are on the short side, I found that the range of lever adjustment is also useless (I would like them even further away).
Needless to say, I am very dissapointed with the brakes. Sorry for writing too much but I thought you should know what happened from day 1 to give proper advice.
Bleed them yourself. If you start pushing fluid from the caliper to the levers and any bubbles evolve out of the port into the reservoir, then you know the system is not sealed right and no amount of rebleeding will keep air out. Maguras really only make noise and lack power if the pads are fouled with oil. I heat my pads with a propane torch lightly until the smoking diminishes to burn contaminants out. I bet the shop was lazy and didn't pull the pads when they bled the brakes. It would really make sense for you to follow the instructions that come with the brakes and bleed your own. I personally would not trust a shop to do it right.
Measure the distance from the grip face to the end of the lever blade and compare it to the distances at the end of this thread. See if you are really getting all the reach the brake offers.
The pads need time to bed in. After bedding, the noise may go away and the power may improve. Otherwise... the pads are fouled.
Sounds like a bad bleed or a leak.
and B+W too
It sounds like the first set of 'good bike technicians' didn't bleed your brakes properly as the second bike shop cured the first shop's problem bleed. I learnt how to bleed my MTB's brakes myself as I'm a believer in the saying 'If you want a job doing well, do it yourself'.
I too have Louise BAT's and have the adjustment set to max. Is that a problem for me? nope. I also find the lever reach adjustment pretty good, as I can set the reach just how I like it.
The 'amazing noise' you mention could be because the calipers are out of align with the rotors. Magura brakes are reknowned for their quietness so I strongly suspect there is something amiss with your slave cylinder/rotor alignment.
Re braking power, Are your pads now contaminated? Have you bedded the pads in? I'm very happy with my Louise's braking power so it sounds to me like your pads are either or both contaminated/not bedded in yet.
I haven't owned any Hayes brakes but my friend was commenting to me last week about his Hayes' on/off lever feel. It seems to me like you might prefer another set of Hayes brakes. Good Luck.
Last edited by RedBlueGreen; 01-07-2008 at 03:20 AM.
Originally Posted by Stefanos
Although I don't have any scientific evidence, I will say that I do not feel any "softness" with Mineral oil. I have experienced brakes with both -DOT and Mineral oil- and I would not be able to tell you the difference between them.
Based on what you described, I would say that either the bleed was not performed correctly, or your pads are contaminated- as pointed out by several posters above.
Try to check to see if the pads are good or not, also flip the bike upside down and see if there is a noticeable difference in the brake lever. If there is, it may indicate a bad bleed job.
Also, I would like to point out that bleeding Magura brakes a HUGE PAIN in the neck, so make sure you follow the steps carefully.
Last edited by anirban; 01-07-2008 at 09:01 AM.
"Winners never quit. Quitters never win. But those who never win and never quit are idiots."
It sounds like the first hose fit/bleed effort had some air leaks at the fittings. I had that problem when I installed a Marta replacement hose the first time. A bleed would work fine for the first 10 squeezes, sometimes a whole day, but the next day, the lever would go to the bars. (live and learn )
Magura's really require that the tech follow the bleed procedure exactly, you can't take any shortcuts, that goes for where to set the lever adjustment, pad retraction, etc., etc.
I'd also agree with the contaminated pad theory for noise and low stopping power. You might try replacing the pads with the Performance pads rather than the Endurance pads, they will be quieter and stop better. The Louise post mounts should be easier than the Marta IS to get aligned, but it still takes some time to get it tweaked, and will likely need another minor tweak after bedding the pads.
Liquids don't compress at all (kind of a fundamental property of liquids and the reason that hydraulic systems work at all), so the fluids won't make any difference in the feel.
" By the way, the guys there told me that mineral oil has a different, more progressive feel than DOT (my old brakes were Hayes HFX-9) and that it is the mineral oil that is causing this 'softness'."
Agree with previous posters that the original problem was residual air in the system. But the guys at shop 2 are not correct in the above quote. It's far more likely that your pads are contaminated with brake fluid. My $0.02 is that no human could generate enough force (nor could the brake seals take the pressure) to show a compressibility difference between DOT and mineral oil brake fluid.
Sounds more like "We're tired of dealing with your brake problem and we will make up a story you can't disprove. Go away."
You will be fighting an uphill battle to get a warranty replacement on this one. My guess is the guys at shop 1 contaminated them, and won't fess up if they even understand what went wrong. I'd try burning the oil out of the pads, or just buy new ones. They aren't that expensive. Too bad your local shop guys are not capable, but as the previous posters said, learn to do it right yourself and you are way ahead. If you have superhuman patience, you could share your newfound expertise with shop 2, but that's up to you.
Magura people have always been great when dealing with warranties.
Originally Posted by Walt Dizzy
But this does not seem like a warranty issue. I have a very strong feeling that a re-bleeding the brakes, and making sure that the pads are good would fix the problem.
"Winners never quit. Quitters never win. But those who never win and never quit are idiots."
With all the talk about brake pad contamination, I feel that a mention of rotor contamination is also necessary. Clean of your rotors with a degreaser (i.e. acetone) to remove any oil that may be on them. Most of the times I get my bike back from servicing at a bike shop, I find braking power to be lacking. I've noticed a significant increase in braking power after cleaning the rotors every time, so it's worth a try considering it doesn't cost a dime if you have a degreaser (nail polish remover also works).
On a related note, I too recently purchased a set of the 08 Louise Carbons but have yet to install them on my bike. These will be my first set of hydros so the bleeding process is new for me, but I feel that it will be worth taking the time to figure out how to do it myself, especially since I am very finicky about my brakes. Is it necessary to use the Magura bleed kit in order to bleed the new Louise brakes, or will Avid, Shimano, etc. bleed kits also do the trick? Also, there was a mention of Magura's being difficult to bleed. Is this still the case with the new Louises, with the bleed port?
You can bleed the Magura with a big syringe and some clear aquarium tubing. An extra hand would be nice... but not necessary. I haven't seen the new Louise... so I don't know.
How can anyone tell whether the fellas at the LBS are experts or bluffers? Answer - you can't until it's too late. Unless Magura's (or any other brakes') instructions are followed to the letter then the brakes aren't bled properly. It's no harder to do it right than to do it wrong. Better to do it yourself as you have more at stake.
Points from your post - neither Magura mineral oil or DOT fluid are compressible; air bubbles are. Poor braking - new brakes need bedding in to reach full power. Oil soaked brakes (due to sheer incompetence) will never reach full power. Bad brakes - there aren't many bad brakes but there are lots of bad brake bleeders.
That is perhaps the best thig I've ever read on this forum!
Originally Posted by Mike T.
Download the bleed instructions, buy the bleed kit and a fresh set of pads, and go to town. After you dial the brake in, take it to both shops with your receipts for the 'labor' performed and ask for a refund. Crow is such a hard thing to eat, but if the shops are good they'll man up and take responsibility. Even the best mechanics make errors, and what seperates them from the bad mechs is that they admmit & correct it as fast as possible.
You are not what you own.
and B+W too
It seems to me this thread should be re-titled 'Amazing Problems with Two Naff Bike Shops and I could do with finding out How to Bleed and Set Up My Brakes'.
I don't see the problems faced by the original poster as being the brake per se, moreso the very poor maintenance of his Maguras. Come to think of it, Avid, Formula, Shimano, Hayes, and Magura kit will all suffer at the hands of vpoor set up and contaminated pads...