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Brakes Chirping over bumps

Discussion in 'E46 (1999-2006)' started by alvocado, Sep 18, 2010.

    • Member

    alvocado

    Post Count: 26
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    I've been trying to chase down an annoying suspension chirp for well over a year and finally pinpointed the source. When I go over sharp bumps in the road, I get a chirp (literally sounds like a bird chip) from either front corner. The noise appears to be coming from the brakes since I was able to eliminate it by keeping light pressure on the brake pedal while test driving over roads that would cause the noise. I never had the issue prior to installing Axxis Deluxe brake pads. Has anyone else experienced issues with pads moving in the calipers and causing noise over bumps? Perhaps the pad spring on the Axxis pads doesn't hold them into the piston as tightly as the German pads. I only have about 15k miles on the Axxis pads but the noise is so annoying, I'm willing to switch back to OEM or Pagid pads if it will correct the problem.
    • Member

    CRKrieger

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    I seriously doubt it's brake pads (I've run Repco/Axxis/PBR Metalmasters for 20 years), but it only takes about 20 minutes to swap them out as a test. So do it.

    For a noise over bumps, I'd look at the antiroll bar bushings or links.
    • Member

    alvocado

    Post Count: 26
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    I originally thought suspension bushings were the likely source as well. I've replaced the LCA and bushings and sway bar end links all with Meyle HD parts. I considered the sway bar bushings but it's strange that the noise isn't present when light brake pressure is applied.
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    tiFreak

    Post Count: 523
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    did you put the anti-rattle clips back in? should be two on each side at each end of the pads, sometimes they can fall out without you noticing
    • Member

    alvocado

    Post Count: 26
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    It's been quite some time since I changed the pads but I only remember the clips which attach to the outside of the caliper. I replaced those on each corner.
    • Member

    alvocado

    Post Count: 26
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    This made me think about the tension on the clips. I replaced them because they were tarnished but I remember the new clips were bent such that they held the pads in tighter. I may try to bend them further so they put more tension on the pads.
    • Member

    tiFreak

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    the one's on the outside of the caliper aren't the ones I'm talking about, they fit in between the caliper bracket and the ends of the pad, kinda like a shim
    • Member

    alvocado

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    Those sound like anti-rattle clips. My Yukon has them but I don't recall my e46 having similar clips when I changed the pads and there are none installed currently. I would have noticed them during replacement if they were present.
    • Member

    dms540i

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    Tell us: how old is the car, what's the mileage and what model and is it emanating from the front or rear? Ball joints sometimes will squeak (chirp, like a bird, IDK). Seems to me there's a suspension bushing or other (dare I say cheap) rubber part at fault here.
    • Member

    alvocado

    Post Count: 26
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    Problem solved. The pads were indeed causing the chirp by moving in the calipers when traveling over sharp bumps. The Axxis Deluxe pads have a very thin backing material which is made of fiberglass. It did a poor job of absorbing vibration and eliminating squeaks, not to mention is was separating from the backing plate after only 3yrs and 20k miles.

    I replaced the Axxis with OEM Pagid pads and the car is 100% noise free over bumps. The backing plate shim is significantly thicker and made of a rubber-like material. Aside from the increased dust, I'm looking forward to having the improved cold bite and OEM brake performance back, not to mention quiet brakes.

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