Brake losing power

[jbiron]

I have four month old Magura Marta SL's. About three weeks ago the front began losing power and over a couple of days I was gradually able to pull the lever all the way to the grip. There was no obvious leak and since I don't have a bleed kit yet I took it to my LBS. They bled it, but after a week the same thing happened. LBS re-bled. This time it worked find for two weeks. Just today I was thinking on my ride it was working great and my problem was solved. However, after cleaning the bike I now can pull the lever all the way to the grip again. Not the slow fade as the last two times, but great on the ride, nothing after cleaning.

No problems so far with the rear.

I'm new to disk brakes. Any advice would be welcomed.

[guero]

take it back to where you got it and ask for a new one...may be a bad o-ring or something inside the piece, causing it to lose pressure and fade?

[thephat]

Yeah, assuming that it was properly bled, you probably have a bad master. Magura has a 5 year waranty, and in my experience, that waranty needs too much use. Check that your pads are not low. Martha brakes run out of fluid to push the pistons out more before the pads are all the way to the metal.

[un-kola]

Originally Posted by jbiron

I have four month old Magura Marta SL's. About three weeks ago the front began losing power and over a couple of days I was gradually able to pull the lever all the way to the grip. There was no obvious leak and since I don't have a bleed kit yet I took it to my LBS. They bled it, but after a week the same thing happened. LBS re-bled. This time it worked find for two weeks. Just today I was thinking on my ride it was working great and my problem was solved. However, after cleaning the bike I now can pull the lever all the way to the grip again. Not the slow fade as the last two times, but great on the ride, nothing after cleaning.

No problems so far with the rear.

I'm new to disk brakes. Any advice would be welcomed.

Sounds like a bad master cylinder.Have them rebuild or replace.- Lloyd

[thephat]

Originally Posted by guero

take it back to where you got it and ask for a new one...may be a bad o-ring or something inside the piece, causing it to lose pressure and fade?

Agreed.

[Pain Freak]

I'm running the same brakes. No problems with mine, but a friend told me he has had a similar experience just like yours. They warrantied them (rear), and all is good over a year later. Awesome brakes too.

[jbiron]

Anybody know if this problem (described in the original post) could be caused by turning the bike upside down?

[un-kola]

Originally Posted by jbiron

Anybody know if this problem (described in the original post) could be caused by turning the bike upside down?

Couldn't tell about Maguras but on my Juicy-7's,if you squeeze the levers after the bike has been hanging by the front wheel,the brakes will be spongy and pull to the handgrips.After I set the bike back on two wheels,I squeeze the brakes a couple of times and everything goes back to normal.- Lloyd

[2wheel_lee]

Originally Posted by un-kola

Couldn't tell about Maguras but on my Juicy-7's,if you squeeze the levers after the bike has been hanging by the front wheel,the brakes will be spongy and pull to the handgrips.After I set the bike back on two wheels,I squeeze the brakes a couple of times and everything goes back to normal.- Lloyd

You have air in your line/caliper/lever. I had a bike that never had a problem with a set of Juicy 7s...until I started hanging it from the front wheel. Then I had the same problem that you described. After I bled the brakes, I no longer had that problem after hanging the bike.