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  1. #1
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    My Hope M4s has lost some power..

    Now, my bike has, regrettably, been rather idle during this winterseason, and it appears it has lost some power on the rear brake for some unknown reason while waiting for me. Also it has become impossible for me to achieve a proper lever feel, which is not the case with the front brake.

    Right, lets go through what I have found out so far step by step:

    1: I felt it required a much harder press to achieve the same stopping power, but not with a mushy "I-must-be-bled-soon" feel.

    2: I pulled of my rear wheel and checked the disc and the pads, and they have plenty of life left.

    3: I thought then it might just need to be readjusted, so I did that with all the bells and whistles. That did not help in any way.

    4: I pulled out the pads and checked the piston movement. And wouldn't you have known, it might just be the reason. They are moving way differently. I tried to "massage" them a bit by pumping them out and pushing them back in gently for a very long time. however it didn't solve it..

    So I arrived at the conclusion that "there is your problem" and actually that could have been put much shorter..

    So now my question! How do I get the pistons to move similarly again?
    Why are my shins so scarred..?

  2. #2
    007
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    Try pushing the pistons out some but before you push them back in wipe them down with a cotton swab soaked with alcohol, let it dry and then repeat with with brake fluid instead of alcohol. Your seals might just be a bit dry.

    It might take a few times to get them moving. I'd probably bleed them too while I were at it.
    Alcohol may lead nowhere, but it sure is the scenic route!

  3. #3
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    I'll try that and bring an update soon.

    Thankfully they are quite easy to bleed
    Why are my shins so scarred..?

  4. #4
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    Red rubber grease works wonders with dry seals if the brake fluid isn't enough. You can get a tub of it large enough to lubricate every brake you'll ever have many times over off ebay for a few bucks.

  5. #5
    007
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    Quote Originally Posted by anlin View Post
    Red rubber grease works wonders with dry seals if the brake fluid isn't enough. You can get a tub of it large enough to lubricate every brake you'll ever have many times over off ebay for a few bucks.
    But doesn't that need to be applied directly to the seal? The piston seals are within the bore and not easily reached without taking the caliper apart.

    Hopefully the brake fluid does the trick. I have to do this regularly here in SoCal from all the dust.
    Alcohol may lead nowhere, but it sure is the scenic route!

  6. #6
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    I've had success simply applying the grease to an extended piston's surface. It should transfer enough of the stuff to the seal to do the trick. It doesn't take a lot of grease to lubricate the piston. Besides, the OP has Hope brakes, which can be completely disassembled.

  7. #7
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    Thought I'd give an update in case someone else has the same problem.

    Finally had the time to do it yesterday and it seems the pistons are now moving properly again. I didn't use grease, just brake fluid, as my grease has mysteriously disappeared.. Now all they need is a bleed, proper adjustment and a spin. Sadly that'll be a couple days..
    Why are my shins so scarred..?

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