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Discussion Starter #1


I have an issue where I get a pretty loud metallic sounding rattle coming from the passenger’s side front wheel well when going about 20mph on a bumpy road. If I apply the brakes while still maintaining 20mph, the noise goes away. At a standstill (without the brakes applied) if I tap on and off the brake pedal fairly quickly I can reproduce the noise.

Dave Z suggested that my Porterfield R4S pads may be to blame due to bad fitment. He also suggested I replace the anti-rattle clips in case they were bent out of shape or something. Today I installed new OEM pads and anti-rattle clips. The noise is still present under the same conditions.

This is driving me crazy! I want to say it is something to do with suspension, but it goes away when the brake pedal is applied.

Does anyone have any ideas or things to try? I am willing to try almost anything right now!

Thanks in advance for any help… josh
 

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DavidS said:
Maybe it is a cracked brake caliper?

David
Something is loose, that stops with pad pressure. Are all the carrier bolts tight? Have you checked your rotor for cracks? Any stones caught inside the dust shields (if they are still on the car)?
Regards,
Jerry
 

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Discussion Starter #4
Thanks for the replies guys. The rotors look fine, as do the calipers. I've been wondering about the shields, but pad pressure wouldn't affect the shields, would it?

thanks again and keep the ideas coming!

...josh
 

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i wonder if you have something loose in the suspension, like a control arm or a ball joint and brake pressure applies torque to the loose part and makes the noise stop. I had a knocking sound from my front end about a year ago, my dealer found a "control arm not torqued to spec" which they tightened and the noise went away.
mike
 

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jkarp,

I would have bet the house the pads and the anti rattle clips would have cured the problem as Dave Z mentioned. If it's still doing the same thing with no change check the anti rattle clips one more time just to make sure they are tight. If they are try checking the sway bar links in the front. They get loose and rattle over bumps. It's very common problem in the front end of alot of BMW's. Although I never heard one stop making noise when you apply the brake but stranger things have happened.


Hope it helps,
Joe
 

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jkarp said:
Thanks for the replies guys. The rotors look fine, as do the calipers. I've been wondering about the shields, but pad pressure wouldn't affect the shields, would it?

thanks again and keep the ideas coming!

...josh
OK, just for grins, put a whole bunch of anti squeal on the backing plates. If that helps, then a pad is loose, and if you hear it only on the right side, that is it. If not, look elsewhere, but as others have noted, classic symtoms of a loose pad. I assume the pistons are not retracting too far, which would also allow the pad to be loose. Unlikely, as usually they stick by failing to retract, but no harm in looking!
Never looked at pads so I don't know if inner and outer are different, but if they are, make sure they are oriented correctly. If not, does switching inner and outer help?
Regards,
Jerry
 
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