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  1. #1
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    Magura Louise FR pads not self adjusting?

    My buddy has these brakes. The rear caliper seems to be giving him some trouble. He has never bled the brakes, but we don't know if this would solve his problem... After changing pads in the rear, he mounts the caliper to the frame. If he aligns the rotor to the center of the caliper the pads are dragging. These brakes are supposed to self center and adjust aren't they? I might be that the inside pads is not retracting all the way, but I'm not sure.

    I'll have him chime in here to see what part of the situation I've gotten wrong. But what advice can you give him?

  2. #2
    Meh.
    Reputation: XSL_WiLL's Avatar
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    No. You still haver the center the caliper manually. The pistons self adjust for pad wear. You need to reset the pistons after changing the pads.

  3. #3
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    Quote Originally Posted by XSL_WiLL
    No. You still haver the center the caliper manually. The pistons self adjust for pad wear. You need to reset the pistons after changing the pads.
    Caliper is centered. Pads are pushing/rubbing the rotor.

  4. #4
    Meh.
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    Clean and lube the pistons if necessary. Pump out the pistons a bit, lube with mineral oil and cycle the pistons in and out.

    Before that... I'd reset the pistons, center the caliper again. It certainly does not sound centered from the way you are describing it.

  5. #5
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    Quote Originally Posted by XSL_WiLL
    Clean and lube the pistons if necessary. Pump out the pistons a bit, lube with mineral oil and cycle the pistons in and out.

    Before that... I'd reset the pistons, center the caliper again. It certainly does not sound centered from the way you are describing it.
    How do you 'reset' the pistons? My friend will probably understand better than me, but I figured I should ask. (I use BB7's cause I'm stupid)

  6. #6
    No, that's not phonetic
    Reputation: tscheezy's Avatar
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    Remove the wheel from the bike. Use a plastic object like a clean tire lever to push on the pads until they are shoved well back into the caliper (spread them apart to increase the gap between them where the rotor would sit). This is "resetting" the pistons. Put the wheel back on the bike. Slowly pump the brake lever and watch the pads advance back towards the rotor. The brake will feel soft and it will take a few squeezes for the pads to advance. Notice that one pad may advance more than the other. This is ok, but once one pad has moved more, you can gently bend the rotor (push on it with paper towels so you don't get grease on the rotor) towards the advancing pad to hold it back, and force the other pad to move instead as you squeeze the lever. Keep doing this. Advance the pad and force the pistons to emerge evenly. Once you are done and the pads squeeze the rotor, you can still push on the rotor to force one pad back or hold it in place if you want the other pad to move forward by squeezing the lever. The pistons (and pads) "float" in the caliper. You can determine where they sit in relation to the rotor. If one is a little sticky, the other will advance more and cause rubbing. "Resetting" the pistons often helps with this.
    My video techniques can be found in this thread.

  7. #7
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    Quote Originally Posted by tscheezy
    Remove the wheel from the bike. Use a plastic object like a clean tire lever to push on the pads until they are shoved well back into the caliper (spread them apart to increase the gap between them where the rotor would sit). This is "resetting" the pistons. Put the wheel back on the bike. Slowly pump the brake lever and watch the pads advance back towards the rotor. The brake will feel soft and it will take a few squeezes for the pads to advance. Notice that one pad may advance more than the other. This is ok, but once one pad has moved more, you can gently bend the rotor (push on it with paper towels so you don't get grease on the rotor) towards the advancing pad to hold it back, and force the other pad to move instead as you squeeze the lever. Keep doing this. Advance the pad and force the pistons to emerge evenly. Once you are done and the pads squeeze the rotor, you can still push on the rotor to force one pad back or hold it in place if you want the other pad to move forward by squeezing the lever. The pistons (and pads) "float" in the caliper. You can determine where they sit in relation to the rotor. If one is a little sticky, the other will advance more and cause rubbing. "Resetting" the pistons often helps with this.
    THANKS! We'll give that a try.

  8. #8
    Daniel the Dog
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    Bleeding may be in order

    I battled some Maggies for a year that were defective and leaking. I think Cheesy is right though. He is the expert, just ask him , and sounds like he has directed you on the path of quiet brakes.

    Jaybo

  9. #9
    Do It Yourself
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    I agree about reanimating the seals and resetting the pads. However, I've found that sometimes the pads just want to sit off center a bit for whatever reason. If it's just a mm or two, you may be able to shim the caliper just off center to match the "natural" position of the pads as long as the rotor doesn't hit the caliper.
    Long Live Long Rides

  10. #10
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    Thank you all for the comments. I pulled the wheel off and slowly pulled my brake lever, one side moved and the other wasn't. I took out the pads, used a clean pedal wrench to give the unstuck piston something to push against without going past middle so it wouldn't come all the way out, then squeezed my levers with increasing force until the stuck piston came loose and out to center. Then cleaned and lubed the pistons while they were out in center with a q-tip and a little mineral oil. No sticking now, nice and smooth. Thanks again for the great tips!
    -SnakeCharmer

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