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dead weight
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Discussion Starter #1
My front brake (2003 Magura Marta) does not maintain its performance. I have had to take it to my mechanic about every two months for the last year. He bleeds the brake and says "maybe some air got in" and the brake works great for another couple of months.

Two days ago, the brake was working fine but the pads wore out. So I replaced the pads with Marta performance pads. I was very careful not to contaminate the pads or rotors. As soon as I got the new pads installed, the brakes performance was terrible. I did several "panic stops" to wear the pads in and other more gradual stops as well. The brake lever travels nearly to the handlebar and there is not much stopping power. I can squeeze the brake lever and pedal through!

So my question is, what is wrong with the brake? My rear brake (also Marta) does not exhibit this behavior. Could it be a defect in the brake somewhere? I shouldn't have to get the brake bled every time I change pads or every two months should I?

I emailed this same question to [email protected] a minute ago so we'll see what they say too. Any other help would be greatly appreciated.

Jack
 

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Bodhisattva
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Air can be introduced into the system when the pads are severely worn and that likely explains your most recent problem.

I suspect that poor bleed technique & occult air trapping is the culprit for your repeated bleeds. Once bled properly they shouldn't need bleeding for at least a year.

Check out the Magura Cult page for comprehensive bleeding instructions and try to do it yourself.
 

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dead weight
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Discussion Starter #3
I don't think the old pads are severely worn. I changed them as soon as performance decreased. When I measure the old pad thickness using the yellow thing that Magura includes, one of the pads just fits inside the groove along one part of the pad. The other pad does not fit in the groove that indicates it's time to replace. I'm not trying to nit-pick words, but I would consider this wear to be the normal when it's time to replace pads and not excessive wear. The rear brake does not exhibit the problem and I wear the pads just as far too. As a matter of fact I recently replaced the rear pads and they were even more worn, but the brake worked fine after the replacement. I would hope that Magura's own specs on when to replace pads would not be so far into wear that the brakes require a bleed.

Thanks for the info though. I might try to bleed them myself, but considering how many times they've been bled, I have to wonder if there is another cause.

Jack
 

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Do It Yourself
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You just need some new Louise FR like your bro and sell those Martas to some XC racer weenie. Speaking of which, is Mark's rear brake okay since we last bled it?
 

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dead weight
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Discussion Starter #5
Homebrew said:
You just need some new Louise FR like your bro and sell those Martas to some XC racer weenie. Speaking of which, is Mark's rear brake okay since we last bled it?
So are you offering to trade your Lousie FR's for my Martas?

Mark's brakes seemed fine. At least he didn't say anything about them, so I guess there are working well.
 

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Do It Yourself
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JackFromNC said:
So are you offering to trade your Lousie FR's for my Martas?

Mark's brakes seemed fine. At least he didn't say anything about them, so I guess there are working well.
At the going rates, you can sell your used Martas for about the same as a new set of Louise. That's what I did and came out even. You probably want to bleed them before you sell though. I can help if you want or have Frank try again.

I just talked to Mark. He said his Louise were much better and worked great. Sounds like you guys had a nice trip to Slatyfork. Sure, it's no TR but looked like some good trails.
 

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dead weight
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Discussion Starter #7
I wouldn't feel right about selling them unless I can get this problem fixed for real, and not just another bleed.

Frank is out until next Tuesday and they didn't even have the Royal Blood mineral oil in stock. I may have to take you up on the bleed offer. I'll give you a call later.

Jack
 

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www.justthebonnet.com
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Hey Jack I'll trade you some avid mech's for those "weight weenie" martas! Mine have been fine for the past two years! Sorry bout your brake, add it to the list of Slatyfork causulties!
 

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dead weight
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Discussion Starter #9
I actually love my Martas..... when they work properly, so no trade yet. The front one just gives me a hard time every month or two. I'll give it another shot and if it won't hold, I'll have to send it back to Magura.
 

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First off, you can introduce air into a hydraulic disk brake system by laying the bike on its side or flipping it over. Letting the master cylinder run dry will do it too. As the brake pads wear, the brake pistons migrate in toward the rotors, pulling more fluid into the system and lowering the fluid level in the master cylinder. Keep an eye on it and top it off as necessary (like you do in your car).

New pads need to bed into the rotor. It usually takes a few rides. Did you damage (deep grooves) the rotor when the pads wore out? This could make them impossible to fully bed in. When I replace pads, I like to clean the rotors with a alcohol and a Scotch Brite pad then spray them with automotive brake cleaner. Don’t forget to remove the master cylinder cover to let out the extra fluid when you push the brake pistons back in.
 

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JackFromNC said:
My front brake (2003 Magura Marta) does not maintain its performance. I have had to take it to my mechanic about every two months for the last year. He bleeds the brake and says "maybe some air got in" and the brake works great for another couple of months.

Two days ago, the brake was working fine but the pads wore out. So I replaced the pads with Marta performance pads. I was very careful not to contaminate the pads or rotors. As soon as I got the new pads installed, the brakes performance was terrible. I did several "panic stops" to wear the pads in and other more gradual stops as well. The brake lever travels nearly to the handlebar and there is not much stopping power. I can squeeze the brake lever and pedal through!

So my question is, what is wrong with the brake? My rear brake (also Marta) does not exhibit this behavior. Could it be a defect in the brake somewhere? I shouldn't have to get the brake bled every time I change pads or every two months should I?

I emailed this same question to [email protected] a minute ago so we'll see what they say too. Any other help would be greatly appreciated.

Jack
I have the same problem, I must bleed them about once a month or even more often after a violent endo...Not what I signed on for when I purchased them!!
 

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Jack,

Sorry for the problem and sorry I was not in town. I was in Colorado at the DT Swiss press camp that I was invited to and then wrenching for some pro riders at the NORBA National in Snowmass. Give me a call, and we can remedy this situation if Magura has not already. I know my bleed technique is correct. Every time you have brought me the brakes, I have looked for every problem that I have seen and know of at this current time. I even have checked for a bad or leaking seals in the master cylinder and found nothing. And I have seen most of the (very little) issues after being at the Magura truck for almost every NORBA Nationals for the past 3 years. The last time you brought the bike in, the pads were severly worn, and I replaced them and bled the system. If you are still having problems, please let me know. When I do not here from you, I assume there is no problems. Maybe I should not assume. I will talk to Magura, and we can fix this problem.

Frank
 

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No, that's not phonetic
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Does the Marta use a flexible diaphragm in the reservoir? As the fluid level gets drawn down, is there a membrane which separates the resulting void space from the fluid? My Juicys have a transparent flexible reservoir which can deform to allow changes in fluid volume without actually establishing an air-fluid interface. Is this the case with the Martas too? I guess it must be, otherwise fluid would either leak out the vent holes or the system would not be able to deal with changing fluid volumes.

If you flip a bike over with Juicys and squeeze the lever, it can allow a bubble into the hose. It never happens unless you squeeze the lever though, and out of the many times I have done this it has only resulted in a need to bleed once.

I had toyed with getting some Martas for my GF's bike, but she's not a tech-head and never-need-to-muck-with-it reliabilty is paramount (Vanilla shocks, Avid mech brakes, etc).
 

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Bodhisattva
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Yes, there is a flexible diaphragm in the reservoir under the top cap.

I don't have Martas & those I personally know who own them have had no problems but there have been a number of reports of problems here.

I'd suggest you take a look at Louise for the GF. It's only a minimal weight gain and they seem to be a bit more reliable. I've had zero problems with 2 different sets/generation of Louise over the past 3 years.
 
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