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  1. #1
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    Noise from hydraulic brakes

    Hello all,

    I'm in the process of overhauling and building up my 2004 RMB Hammer (steel frame) and could use some advice on the brakes.

    The OEM brakes were Shimano M525 and they worked fine, but the regular scraping/hissing noise from the rear annoyed me no end. After a couple of years I had a local shop take a look and they assured me that the solution was a new set of Juicy 3.5 (IIRC). Nope. Still noisy. So, is this common to all hydraulic brakes due to the self-adjustment feature? And is it more likely due to flex in my steel frame's rear (albeit small) triangle?

    And where I'm going with this is I'd really appreciate some advice on where I should go from here. I'm free to start again and can therefore go to cable discs if that's likely to be a solution. Cost and weight are less of an issue than simplicity and noise-free riding.

    My riding is predominantly cross-country; there are virtually no decent grades where I live; I'm just on 80kgs; and I ride both bitumen and trail.

    Any help would be great!

  2. #2
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    Is it a constant scraping? if it is, it is most likely the rotor is not centered in the caliper. How to fix this depends on which type of mount you have. If is an periodic scraping, it is most likely a bent rotor, and the rotor needs to be straitened. If it is scraping that only happens in some situations then it is most likely frame flex. If it is a howling sound, it could be glazed or contaminated pads or rotor, which should be cleaned or replaced.

    Hydraulic brakes are not inherently noisy, noise is a sign of some sort of problem.

  3. #3
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    Thanks theboomboo. It's not constant. At least not that I can tell. It's more of a regular rubbing/ tss, tss, tss kind of sound. It's been a while (the frame's been up in the roof of my shed until recently) but I think it was a one pedal down = noise thing. And not just in some situations: if I rode around the corner for milk it would do it. Never any howling though.

    The mounts are IS as the frame and forks are 2004. I thought it might be a rotor, but two shops said they were fine after I'd checked and found no issues, and I was (naively) sold new rotors with the new brakes and the noise returned anyway.

  4. #4
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    So no noise when coasting just when you are on the down stroke with the pedals? Is it both sides, or just on one side?

    If it makes the sound on the down stroke while pedaling, it could be the wheel isn't clamped properly with the QR, it could be the cones are a bit loose, chain stay flex, or something that I am not familiar with.

  5. #5
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    Cheers theboomboomcars (sorry, missed the mcars last time). Nothing when I'm coasting as far as I can recall. And just on one side, I think.

    I'd be REALLY surprised if the wheel wasn't clamped properly, as I've had the rear wheel out many, many times to fix flats and to transport the bike, the skewers are solid, and I've been riding with QRs since 1989. So, out of what's left I really hope it's the cones (Shimano Deore Disc hubs, so I'm guessing this would apply). And excuse any vague details as my bike is in bits and I'm a couple of thousand miles from it anyway.

    If it is in fact chain stay flex I'm guessing this will be much harder to resolve. Would I then need to look at cable discs and winding the pads out if I'm to avoid this noise?

  6. #6
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    I think the cones are sounding like a good place to start. If the problem is chain stay flex I don't know if cable discs will help, most cable brakes have one moving piston and one fixed piston and the rotor is gent slightly when the brake is engaged, if the fixed piston is too far out, it can be bad for the rotor.

  7. #7
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    Thanks. I'll see how I go then once it's all back together. Fingers crossed.

  8. #8
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    This can be dangerous but maybe you can isolate the noise by removing the rear caliper (ziptie to the frame) or even better remove the rotor (place a wedge on the caliper) at least that way you can figure in a hurry if is a brake problem or something else.

    Also a few company's make 135x10 and 135x12mm hubs with "Fun bolts" that provide a noticeable improvement in rigidity over a standard QR set up

  9. #9
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    Thanks patineto. I'll look into that. I had been leaning towards White Industries hubs, but I can't see an option for those that would work with my frame. Maybe I'll go with Chris King instead.

  10. #10
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    Quote Originally Posted by J.C.C. View Post
    Thanks patineto. I'll look into that. I had been leaning towards White Industries hubs, but I can't see an option for those that would work with my frame. Maybe I'll go with Chris King instead.
    Glad I can help

    kings are the eh!t but Hadley's are really good too and a lot cheaper

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