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  1. #1
    Mythical Creature
    Reputation: glenzx's Avatar
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    Marta piston travel question

    I've abused my Marta's this seaons pretty significantly, and they have performed incredibly! I only bled them at initial hose length/set-up, and after 1-2 days thereafter, had 'em dialed. Lately, I've noticed that the front caliper seems to exhibit less piston-retraction. Just wondering if besides a cleab & bleed if there are other maintenence issues I should consider..... like is there a need to remove the piston(s) and clean the bores? I'd bet not, considering they still look pretty clean and it'd be an excellent contamination oppurtunity!

    I just can't believ how powerful these brakes are for how light they are. I bomb wicked descents pretty aggressively, and they offer pretty amazing modulation & power, hot or cold.
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  2. #2
    Bodhisattva
    Reputation: The Squeaky Wheel's Avatar
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    Could be that some grit has gotten stuck on the piston and is preventing proper retraction.

    Here's what I would do:
    1- try reactuating the piston. Remove the pads and with a plastic tire lever hold the unaffected piston flush against the caliper body while you actuate the lever. This will force the affected piston to extend. Don't over extend it or you might get fluid lock (I had this happen once & it sucked). Push it back in with a plastic lever & repeat a few times.

    If that doesn't work then...

    2- Recatuate the piston but this time clean the piston with an alcohol soaked q-tip before pushing it back in. You can then apply a very thin layer of Magura blood to the piston before pushing it back in. Don't put on too much or it will attract dirt. Just wipe it on with a q-tip or your finger (Magura doesn't officially endorse this, but they do it anyway).
    “Life is like riding a bicycle. To keep your balance, you must keep moving.”

    ― Albert Einstein

  3. #3
    Mythical Creature
    Reputation: glenzx's Avatar
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    Quote Originally Posted by The Squeaky Wheel
    Could be that some grit has gotten stuck on the piston and is preventing proper retraction.

    Here's what I would do:
    1- try reactuating the piston. Remove the pads and with a plastic tire lever hold the unaffected piston flush against the caliper body while you actuate the lever. This will force the affected piston to extend. Don't over extend it or you might get fluid lock (I had this happen once & it sucked). Push it back in with a plastic lever & repeat a few times.

    If that doesn't work then...

    2- Recatuate the piston but this time clean the piston with an alcohol soaked q-tip before pushing it back in. You can then apply a very thin layer of Magura blood to the piston before pushing it back in. Don't put on too much or it will attract dirt. Just wipe it on with a q-tip or your finger (Magura doesn't officially endorse this, but they do it anyway).
    Excellent advice! I was thinking about doing the 'pump the affected piston out' a little and see if it looked dirty there..... good note about putting a little "blood" around the piston before easing it back in too.... thanks again!
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  4. #4
    Bodhisattva
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    tis nuttin'

    Magoooooraaaahhhhhh
    “Life is like riding a bicycle. To keep your balance, you must keep moving.”

    ― Albert Einstein

  5. #5
    The Riddler
    Reputation: Kaparzo's Avatar
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    Try White Lightening Clean Streak, it works even better!

  6. #6
    (aka SS_MB-7)
    Reputation: 1speed_Mike's Avatar
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    Quote Originally Posted by Kaparzo
    Try White Lightening Clean Streak, it works even better!
    Yes, this was recommended to me by Shimano Canada when I had issues with my XTR's sticky piston syndrome. It worked only temporarily.
    Ride Hard,
    Mike B. (MCM# 7.77)
    http://www.one-speed.com

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