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Thread: Frozen Brakes

  1. #1
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    Frozen Brakes

    I was out yesterday AM for an early ride in 15-20 degree weather. An hour into the ride and immediately after a 2 stream crossings, my hydraulic brakes did not work at all, I could not pull the levers at all. I am pretty new at below freezing riding and would like to know why this happened and what I can do to prevent it.

    Thanks in advance.

  2. #2
    bi-winning
    Reputation: rkj__'s Avatar
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    Water probably froze around the piston, preventing the fluid from pushing them out.

    I don't know how to prevent that from happening.
    When under pressure, your level of performance will sink to your level of preparation.


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  3. #3
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    What kind of brakes? I had the previous generation XTs and one of them would lock up after several uses when the temps were low 20s and below. The shimano tech I talked too just said that that can happen in really cold temps and there wasn't anything I could do about it. None of my other shimanos (4 sets) have ever done that.

  4. #4
    Meh.
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    It has been suggested that there may be moisture in the lines. And since mineral oil is not hygroscopic... the moisture could be freezing up and preventing fluid from flowing.

  5. #5
    nnn
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    Also in the cold it's a good habit to just dab the brakes every so often to keep their temperature up and hopefully prevent freezing. Some cars do this automatically so I guess it's a good idea

  6. #6
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    It is also highly.....

    adviseable to avoid water corssings in subfreezing temperatures. During a stream or other water corssing moisture gets on things and freezes. I've had moisture freeze up on rim braking surfaces and make the brakes useless. I've had moisture get into calipers and had them freeze up in the same way you describe. I've even had a front caliper freeze in the applied position while waiting at a stop light on my van, deep snow, very cold temps and warm rotors that cooled down enough are all it takes. So it does happen. The only way to avoid it is avoide heavy moisture, i.e. avoid riding trails with open water crossings when the temps are freezing or below. And there could be other problems as well. As WiLL mentioned, moisture in the lines and the stream corssings were just incidental to the freeze up. So next ride, avoid open water. If it happens then, bleed out the brakes to remove any possible moisture in the lines. My guess is from what you describe, you got water in and around the calipers and it froze.

    Good Dirt
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