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  1. #1
    mnoutain bkie rdier
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    What just happened?

    1. Trimmed and reinstalled XTR hoses (new m985 race fwiw)

    2. Squeezed brakes to re calibrate to red supplied spacers

    3. Felt great after a few pulls

    4. Went back to check on them 2 min later and the lever went to the grip w/ little resistance

    5. Hmm...put wheel on bike, took bike off stand, squeezed brakes a few times and they feel perfecto against disc now.

    6. Should I be concerned or just go with it??
    Last edited by rydbyk; 02-13-2012 at 03:57 PM.

  2. #2
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    Sounds like air in the lines.

    Do a bleed.

  3. #3
    mnoutain bkie rdier
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    Quote Originally Posted by AndyN View Post
    Sounds like air in the lines.

    Do a bleed.
    Any explanation for why they feel perfect now?

    Is this something that will go bad again, or should I just wait?

    Ideas?

    I know the XTRs have a "blow off" valve....perhaps this explains it?

  4. #4
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    Air in the system can move around. Depending where it is, the brakes may or may not function. Air is compressible, fluid is not. If the air is trapped in your reservoir, the brakes should work since the compressing action of the brake lever is downstream from the reservoir and trapped air. Air at the caliper will compress when you squeeze the brake lever leading to loss of brake power, or complete loss of braking.

    Turn your bike upside down and squeeze the levers. If there is air in your system I'd expect it to displace from the reservoir and cause brake failure again.

    Not familiar w/XTR and the blow-off valve.

  5. #5
    mnoutain bkie rdier
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    Quote Originally Posted by AndyN View Post
    Air in the system can move around. Depending where it is, the brakes may or may not function. Air is compressible, fluid is not. If the air is trapped in your reservoir, the brakes should work since the compressing action of the brake lever is downstream from the reservoir and trapped air. Air at the caliper will compress when you squeeze the brake lever leading to loss of brake power, or complete loss of braking.

    Turn your bike upside down and squeeze the levers. If there is air in your system I'd expect it to displace from the reservoir and cause brake failure again.

    Not familiar w/XTR and the blow-off valve.
    Bike was upside down (after bike was removed from stand) when the lever went down to grip thingy happened. Now that the the bike is rightside up....seems to be working perfectly.

    So...I am I good in your opinion?

    Thx

  6. #6
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    Quote Originally Posted by rydbyk View Post
    So...I am I good in your opinion?
    No. You should bleed them.

    Why risk your well being over a simple procedure.

  7. #7
    007
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    Quote Originally Posted by AndyN View Post
    No. You should bleed them.

    Why risk your well being over a simple procedure.
    You definitely need to bleed your lines. But its up to you if you do . . . its your face.
    Alcohol may lead nowhere, but it sure is the scenic route!

  8. #8
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    Put the bike back in the stand and orientate it so the brake caliper or lever is at the highest point (air rises).
    Bleed the system, then leave it for 5mins and rebelled, leave it another 5 and then rebleed again.
    Alternatively look at the Avid bleed kit/proceedure. One end is closed and a syringe is used at the other to suck air out using vacuum pressure. A few have used it successfully.
    MTB:
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  9. #9
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    Air in the reservoir moved into the master cylinder as you turned it upside down. When righted again the air was "burped" from the system. That would be my guess.

    Shimano clearly states that the brakes are not to placed upside down once on the bike.

  10. #10
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    air---bleed---enjoy

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