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  1. #1
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    Broken Caliper Piston on Shimano XT Brakes

    While I've loved my XTs for the past 2 years or so, just today I encountered a big problem. When I took off the pads from the rear caliper to change them out, I noticed a little bit of what looked like a rock. Upon closer inspection it was actually a little chip off the right side piston. I figured no biggie, just install the new pads and maybe it'll be OK. Unfortunately, it was NOT. Once the wheel was back on, the first time I pumped the brake lever the piston cracked and fluid started coming out.

    The good news is that my LBS is going to handle the warranty through Shimano and they said it wouldn't be a problem. So hopefully they have stock of those little pistons or will ship me out a new caliper. Will update this post with what happens.
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  2. #2
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    Thats the first time I've heard of that. Was it a composite piston?
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  3. #3
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    It looks like some sort of ceramic material.
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  4. #4
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    Probably phenolic . . . Hope uses the same material and its very fragile
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  5. #5
    wyrd bi ful rd
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    Very unlucky of you, don't let it put your off ... is this the BR-M785s?

    Would not be surprised for you to get a new caliper ...

  6. #6
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    Quote Originally Posted by chinaman View Post
    Very unlucky of you, don't let it put your off ... is this the BR-M785s?

    Would not be surprised for you to get a new caliper ...
    I won't, these brakes have been great the whole time. The LBS said they were sure Shimano would replace either the piston or the caliper.
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  7. #7
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    LBS called today and said that Shimano is sending out a new caliper, so it'll just be $20 for labor to install and bleed the brakes. They're even including a set of new brake pads, in case the old ones were fouled by the oil. They said this was not common, so probably just a fluke or I buggered the pistons maybe at some point.
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  8. #8
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    One more reason to ride Shimano brakes!!!! Ready to get me some SLX's again....

  9. #9
    wyrd bi ful rd
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    Quote Originally Posted by TwoHeadsBrewing View Post
    LBS called today and said that Shimano is sending out a new caliper, so it'll just be $20 for labor to install and bleed the brakes. They're even including a set of new brake pads, in case the old ones were fouled by the oil. They said this was not common, so probably just a fluke or I buggered the pistons maybe at some point.
    Don't see how you could have buggered a piston. Would have just been a defect during manufacturing ... One of those things ... Shimano do not sell individual components for their brakes because they do not expect any of the components to be replaced other than the pads.

    I am sure if you made more noise, the LBS will bleed the brakes for free, and send the bill to Shimano. But you cannot really complain.

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