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  1. #1
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    Bonking ... not feelin' well Disc brake issues in general and Marta SL in particular

    I just got a new bike which I've been riding for a little over a month. The frame kind of forced you to use disc brakes so I went all out and spec'd Mavic 717 disc wheels with Chris King hubs. I opted for Magura Marta SLs for the weight savings.

    Initially the brakes felt great. Then the rear got progessively more mushy feeling each ride. I took the bike in for service and they said the line had air in it so it needed to be bled. Again, the brakes felt ok for a few weeks then the mushy feeling was back. This time the rear stopped working entirely. Does this sound like the rear was setup badly? Should I have them re-installed? I don't see fluid anywhere so it doesn't seem to be leaking.

    Looking through the posts, it looks like the martas have mixed reviews. Should I stick it out or start looking for another brake? The front brake seems ok, but I'm a bit worried now. My riding style can be described as aggressive XC in very dry conditions and I weigh 140lbs. Right now, I really wish I could go back to V brakes but I'm stuck with this wheelset. To me, the discs seem more complicated and heavier. Bad things when you are 20 miles into the backcountry. Maybe things will get better.

    Thanks for any advice.

    --
    Don

  2. #2
    Kam
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    i had the same problem...

    i had the same problem when i ran martas (prior to the martas, i was running avid mechs). the martas needed very frequent bleeding, i'd say every 6 or 7th ride. they felt great...the best modulation of any disc i have used to date, and the power was good. but, come that 6-7th ride, and they would get spongy (this happed about 3 times for the rear, and once for the front). i emailed magura and got a reply stating that there was air in the lines, and they needed to be rebled...no duh!!!

    so, i rebled them each time this happed, got sick of it, and sold them. i switched over to a xt lever/xtr caliper set up, and haven't had the "air in the lines" problem at all...but i did have the sticky piston issue (shimano sent new calipers in about 1 week). i still haven't ridin' those yet...i will give 'em a try later this week.

    i have mono minis on another ride and they have been superb!!! no noise, good modulation and power...and look great to boot.

    sorry i can't comment on what's causing your problem....but i have read a few posts about frequent re-bleeding on martas. i really wanted to keep the martas, and still lust for that feeling, but i hate bleeding barkes once a month (or maybe more frequent than that). hydro discs are supposed to be "install and forget", but my martas weren't.

    good luck.


    Quote Originally Posted by don_o
    I just got a new bike which I've been riding for a little over a month. The frame kind of forced you to use disc brakes so I went all out and spec'd Mavic 717 disc wheels with Chris King hubs. I opted for Magura Marta SLs for the weight savings.

    Initially the brakes felt great. Then the rear got progessively more mushy feeling each ride. I took the bike in for service and they said the line had air in it so it needed to be bled. Again, the brakes felt ok for a few weeks then the mushy feeling was back. This time the rear stopped working entirely. Does this sound like the rear was setup badly? Should I have them re-installed? I don't see fluid anywhere so it doesn't seem to be leaking.

    Looking through the posts, it looks like the martas have mixed reviews. Should I stick it out or start looking for another brake? The front brake seems ok, but I'm a bit worried now. My riding style can be described as aggressive XC in very dry conditions and I weigh 140lbs. Right now, I really wish I could go back to V brakes but I'm stuck with this wheelset. To me, the discs seem more complicated and heavier. Bad things when you are 20 miles into the backcountry. Maybe things will get better.

    Thanks for any advice.

    --
    Don

    f

  3. #3
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    I'm one of the guys that LOVES my martas. I have the marta though, not the SL but all the mechanics are the same. Anyways, I've had the brakes for 2 years now. First season, I bled the rear once (cuz I had to cut the hose) and didn't touch it at all. Just set it and forget it. Then winter came and I didn't ride my bike....just sat there for 5 months. Started riding again this season and on the 3rd ride or so, I need to pump the rear to get enough power...the lever reached the grip w/o really engaging so to say the least, that just wasn't gonna cut it. So I dealt with it and went home to rebleed it. Figure, it's been one year, things happen. Rebled and the same thing happened. At first it was fine, but then it developed the same problem after 2 rides or so. Now you may think, "Sheeesh, I should really get rid of these brakes cuz it's the same old story again". But, I think that you're looking in the wrong area for the problem. I checked the caliper as well, but with all the crashes and falls, I the mastercylinder gets beat up. I mean, with any moving part, there are going to be problems. So, I called Magura and told them my problem ( I spoke to Lonne and he's a great guy). Told them that I rebled the brakes and it didn't help. He just said, "Ok, I'm sending you another one". Didn't even ask me to send the other one back, didn't ask for a receipt. Nothing. I was in their database though so he remembered me. Since I got the new cylinder, I have had zero problems. And I have never, ever rebled the front brakes. They feel the same as the first day I got them. My buddy just picked up the same set as me and he has had zero problems too.

    My buddies (the majority of them ride Hope mini's) say, "it shouldn't have broken in the first place". Being realistic, things happen. I crash, the cylinder gets knocked around...it's break/leak. They have a 5-year warranty and they honored it w/o any hassle and it's working perfectly. Besides, my buddies all have problems with the hopes as well. Martas have to be be the easiest brake to set up. Piston adjustment is a cinch. No pins, just one screw.

    Now, I know that people have been reporting problems with martas and maybe yours were damaged/defective, I don't know. But you should look at the cylinder too and give magura a call. You've got the brakes already, might as well check.....it doesn't hurt.

    Oh...and they're not heavier than v-brakes.

  4. #4
    (aka SS_MB-7)
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    Quote Originally Posted by don_o
    I just got a new bike which I've been riding for a little over a month. The frame kind of forced you to use disc brakes so I went all out and spec'd Mavic 717 disc wheels with Chris King hubs. I opted for Magura Marta SLs for the weight savings.

    Initially the brakes felt great. Then the rear got progessively more mushy feeling each ride. I took the bike in for service and they said the line had air in it so it needed to be bled. Again, the brakes felt ok for a few weeks then the mushy feeling was back. This time the rear stopped working entirely. Does this sound like the rear was setup badly? Should I have them re-installed? I don't see fluid anywhere so it doesn't seem to be leaking.

    Looking through the posts, it looks like the martas have mixed reviews. Should I stick it out or start looking for another brake? The front brake seems ok, but I'm a bit worried now. My riding style can be described as aggressive XC in very dry conditions and I weigh 140lbs. Right now, I really wish I could go back to V brakes but I'm stuck with this wheelset. To me, the discs seem more complicated and heavier. Bad things when you are 20 miles into the backcountry. Maybe things will get better.

    Thanks for any advice.

    --
    Don
    Don,

    First off, discs are amazing! I've been XC racing on discs for 6+ yrs and would never ever consider going back to V's.

    Second, I've got 2 sets of Marta SLs on both of my MTBs (SS and new Racer X) and both are working perfectly....granted, they've only been used for about 2 months on my SS and 3 weeks on my Racer X. I generally ride 4-5 times per week (~12-15 hours). The set on my SS was used during a solo 24 hr race and they performed flawlessly. The set on my Racer X is performing just as nicely. Niether brake has been touched since the initial installation.

    When installing my Martas, each line had to be cut-to-length and the systems re-bled. I had 0 issues here. I carefully followed the Magura instruction manual, as well as, the tips provided on the Magura Cult page.

    Judging by your post, it does sound like you have air in the system. I'd suggest a thorough re-bleed. Did you need to cut the rear line?
    Ride Hard,
    Mike B. (MCM# 7.77)
    http://www.one-speed.com

  5. #5
    ballbuster
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    Are you storing the bike upside down?

    Quote Originally Posted by don_o
    I just got a new bike which I've been riding for a little over a month. The frame kind of forced you to use disc brakes so I went all out and spec'd Mavic 717 disc wheels with Chris King hubs. I opted for Magura Marta SLs for the weight savings.

    Initially the brakes felt great. Then the rear got progessively more mushy feeling each ride. I took the bike in for service and they said the line had air in it so it needed to be bled. Again, the brakes felt ok for a few weeks then the mushy feeling was back. This time the rear stopped working entirely. Does this sound like the rear was setup badly? Should I have them re-installed? I don't see fluid anywhere so it doesn't seem to be leaking.

    Looking through the posts, it looks like the martas have mixed reviews. Should I stick it out or start looking for another brake? The front brake seems ok, but I'm a bit worried now. My riding style can be described as aggressive XC in very dry conditions and I weigh 140lbs. Right now, I really wish I could go back to V brakes but I'm stuck with this wheelset. To me, the discs seem more complicated and heavier. Bad things when you are 20 miles into the backcountry. Maybe things will get better.

    Thanks for any advice.

    --
    Don
    If the brakes were improperly set up with any air in the resivoir, the air can make it's way into the lines if you store the bike upside down. When the brakes are bled, all of the air should be chased out from under the membrane in the lever before the cover is replaced. If fluid does not come out, air can't get into the system, unless there was air traped in there before.

  6. #6
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    Thanks for all the advice. I don't store the bike upside down, but I have turned it upside down while fixing a few flats. That shouldn't affect it right? Also, I sometimes transport the bike in my car, where is lays sidways. Again, I wouldn't think this would affect it right?

    I took the bike to a mechanic today. He is going to inspect the line for micro leaks for me and re-bleed it. Hopefully this will do the trick. I'm glad that some people are having great luck and performance with them. It gives me hope.

    --
    Don

    Quote Originally Posted by pimpbot
    If the brakes were improperly set up with any air in the resivoir, the air can make it's way into the lines if you store the bike upside down. When the brakes are bled, all of the air should be chased out from under the membrane in the lever before the cover is replaced. If fluid does not come out, air can't get into the system, unless there was air traped in there before.

  7. #7
    Founder: Dirty3hirties
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    Quote Originally Posted by don_o
    Thanks for all the advice. I don't store the bike upside down, but I have turned it upside down while fixing a few flats. That shouldn't affect it right? Also, I sometimes transport the bike in my car, where is lays sidways. Again, I wouldn't think this would affect it right?

    I took the bike to a mechanic today. He is going to inspect the line for micro leaks for me and re-bleed it. Hopefully this will do the trick. I'm glad that some people are having great luck and performance with them. It gives me hope.

    --
    Don
    I have flipped my bike over on numerous occasions. I don't store it like that but I have left it overnight on a few occasions upside down. Haven't had that problem though in the 2 years that I have used these brakes. But if there is air in the cylinder, it'll move up the hose. Just another thing you should check I guess but if you've bled and re-bled your brakes and the problem persists although you're doing everything "correctly", then I would contact Magura. I hope your brakes are fixed whatever the problem may be.....they're great and shouldn't be this much hassle.

  8. #8
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    Quote Originally Posted by don_o
    Thanks for all the advice. I don't store the bike upside down, but I have turned it upside down while fixing a few flats. That shouldn't affect it right? Also, I sometimes transport the bike in my car, where is lays sidways. Again, I wouldn't think this would affect it right?

    I took the bike to a mechanic today. He is going to inspect the line for micro leaks for me and re-bleed it. Hopefully this will do the trick. I'm glad that some people are having great luck and performance with them. It gives me hope.

    --
    Don
    Normally, it's OK to turn the bike upside-down or lay it on its side...just don't pull the lever. This can force air from the upper reservoir (in the master-cylinder) into the line. Also, be careful when pulling the lever when there is not a rotor in the caliper. If done carefully, pulling the lever without a rotor can be used to move the initial piston position...this is typically done to decrease the lever-pull amount before the pads contact the rotor. But, if you pull too far, you can suck air into the caliper.

    I found the Martas to be among the easiest brakes to install and bleed. But, you have to be careful and patient so you don't suck or pull any air into the system.

    Carefully follow the Magura Cult instructions. Remove the pads, push pistons fully into the caliper, install the spacer and make sure the caliper's hose connection is vertical. Unscrew the caliper's bleed valve. Attach a syringe full of new Magura fluid. I've removed the tiny rubber o-ring from the hose connection piece because I found tiny bubbles could easily enter the system. Without the o-ring, I don't seem to have this problem. Gently tighten the connector.

    Loosen and rotate the master-cylinder so that the reservoir is level. Tighten the master-cylinder. Open the master-cylinder reservoir. Push new fluid from the caliper into the reservoir. Use a second syringe to suck-out the overflow fluid from the reservoir. Keep pushing fluid into the caliper and sucking fluid out of the reservoir until the caliper syringe is nearly empty. Then, reverse the process. That is, now use the caliper syringe to suck fluid from the reservoir down to the caliper. Be very careful when sucking because it is very easy to suck too much and have air enter the system from the reservoir.

    Repeat 2-3 times. Then, push the fluid from the caliper one last time. Now, instead of sucking the fluid back down with the syringe, slowly pull the lever to push the fluid down. Make sure you pull slowly. You should get about 15-20 lever pulls. Again, make sure you are continously topping-off the reservoir.

    Almost done. Gently place the master-cylinder rubber bladder and cap on the resevoir, but do not tighten. Just use light thumb-pressure. Now, gently push the caliper syringe. Fluid will slowly escape at the reservoir. While still pushing, tighten the reservoir cap/bladder.

    Once the reservoir cap is tightened, re-install the pads, but remove the caliper mounting bolts so the caliper is free. Insert wheel and place the caliper over the rotor. With the caliper syringe still attached, push the syringe to add more fluid to the system. This will cause the pads/pistons to extend towards the rotor. Push the syringe until there is a slight back-pressure created by the force of the pads against the rotor. Remove the rotor and pads from the caliper. Tilt the caliper so that the bleed valve is pointing upward. Remove the syringe and re-install the bleed-valve plug. Re-install the pads.
    Ride Hard,
    Mike B. (MCM# 7.77)
    http://www.one-speed.com

  9. #9
    A wheelist
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    Quote Originally Posted by don_o
    Thanks for all the advice. I don't store the bike upside down, but I have turned it upside down while fixing a few flats. That shouldn't affect it right? Also, I sometimes transport the bike in my car, where is lays sidways. Again, I wouldn't think this would affect it right?

    I took the bike to a mechanic today. He is going to inspect the line for micro leaks for me and re-bleed it. Hopefully this will do the trick. I'm glad that some people are having great luck and performance with them. It gives me hope.
    Don

    You've gotten some good advice here Don, especially from 1 speed_Mike who's a technically astute guy and who has thoroughly read the bleeding instructions on my Magura Cult pages. They are the latest and greatest bleeding instructions from MaguraUSA and are about three weeks old. If your mechanic isn't using this exact method then he's not doing it right.

    Air may make its way into your system through very limited entry points - if there is no visible external leak. If the reservoir isn't fully topped off (level the reservoir, fill it full, install cap & membrane making fluid overflow and pistons must be pushed and wedged back; there's more so read it!) then when the bike is up-ended and lever operated, air may get into the lines. Always have the yellow Transportation Device between the pads when the rotor is out!

    If levers pull back to the bar after the bike has been just sitting for a while I would be contacting Magura. The physics of this other than "stiff seals travelling through the fluid rather than pushing it" escape me.


    Mike T. (mcm # 717)
    Mike The Bike's home wheelbuilding info - dedicated to providing Newby wheelbuilder information and motivation.

  10. #10
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    Idea! Bleeding Tip

    I just got done bleeding my rear Marta SL brake and found that you can maybe do a little better job if you remove the caliper and lever from the bike when you do it. That way you have a straight line (with no bends that air can "hide" in) from the master cylinder to the caliper. Remember to tap the caliper and lines as you force the fluid upwards towards the lever

  11. #11
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    Quote Originally Posted by delwilli
    I just got done bleeding my rear Marta SL brake and found that you can maybe do a little better job if you remove the caliper and lever from the bike when you do it. That way you have a straight line (with no bends that air can "hide" in) from the master cylinder to the caliper. Remember to tap the caliper and lines as you force the fluid upwards towards the lever
    Agreed. If you can, remove the brakes. But, this isn't always possible, especially from the rear where the hose has been fed through the frame's cable guides.

    Definitely. Gently tap the caliper, line and master-cylinder with a screw-driver to dislodge any trapped bubbles.
    Ride Hard,
    Mike B. (MCM# 7.77)
    http://www.one-speed.com

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