C36 AMG, C43 AMG (W202) 1995 - 2000

question about weird brake noise

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Old 04-28-2011, 01:18 AM
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C63 AMG P30 *EuroCharged*| Porsche Cayenne | Buell XB9SX
question about weird brake noise

when i do hard braking, my brakes, or at least i think it's my brakes, make a weird noise ... sounds like a humming sound, like when you drive over a bridge that has one of those metal grating surfaces, or when you drive on grooved pavement. i also get a "funky" feel through the pedal. "hard braking" = 60-30 braking downhill, or 60-30 on a freeway. i still have 60% pad left in the front and 90% rears. anyone know what this could be? glazing? also, my tires are nearing the end of their useful lives, although not below the wearbars yet. wondering if the weird feel i am getting is related to poor rubber contact with the road. anyone have any ideas?
Old 04-28-2011, 01:45 AM
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i have that right now and think its the rotors being worn down towards minimum thickness combined with maybe uneven brake pad material on the rotors. I dont like the sound either.
Old 04-28-2011, 12:40 PM
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I have the exact same sound, I believe hoontastic is correct regarding having to do with the minimum thickness of the rotor.

Definitely not tire related as I have new tires...
Old 04-28-2011, 01:34 PM
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What do you mean by 'funky' feeling in the pedal? Does it judder, and you get feedback through the pedal? That could mean the rotor is warped slightly. If so, you can machine them down a tad to make them true again. There are plenty of people who are against this, but I've done it before on other cars and have had no issue, as long as you are still within the thickness guidelines, and don't machine too much off. For what is a pad clamping on a rotor other than machining but with a much less abrasive material? Beats buying new rotors, especially on C43/E55/CLK55 because they're so expensive.

Removing the wheel and looking at the rotor, is there a ridge on the outer edge of the rotor? If so, that is a sign that the rotors are nearly used up. There are minimum thickness values for them. I can't recall if it's stamped onto the rotor or not though. You need a special set of calipers to measure rotor thickness.

Here's MarcusF's page on brake specs:

http://www.marcusfitzhugh.com/CLK/DIY/brspec202.html
Old 04-29-2011, 08:32 PM
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Originally Posted by Saaboteur
What do you mean by 'funky' feeling in the pedal? Does it judder, and you get feedback through the pedal? That could mean the rotor is warped slightly. If so, you can machine them down a tad to make them true again. There are plenty of people who are against this, but I've done it before on other cars and have had no issue, as long as you are still within the thickness guidelines, and don't machine too much off. For what is a pad clamping on a rotor other than machining but with a much less abrasive material? Beats buying new rotors, especially on C43/E55/CLK55 because they're so expensive.

Removing the wheel and looking at the rotor, is there a ridge on the outer edge of the rotor? If so, that is a sign that the rotors are nearly used up. There are minimum thickness values for them. I can't recall if it's stamped onto the rotor or not though. You need a special set of calipers to measure rotor thickness.

Here's MarcusF's page on brake specs:

http://www.marcusfitzhugh.com/CLK/DIY/brspec202.html
i have a small ridge on the front rotors and definitely a much larger ridge on the rears. i replaced the front rotors about 20k miles ago along with all the pads, but i never changed the rear rotors. i know i definitely have to change the rears. and the funky feeling i am getting through the pedal is an "on and off" feel (the juddering that you mention), so i think you guys are right in thinking that either the rotors are warped or have pad material build up in spots ...
Old 04-29-2011, 10:04 PM
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I have crazy sqeeky sound from my brakes. While my impedence on brake noise level is probably higer than usual, its so embarassing when I catch attention of other driver.
When time comes I will follow the same root as Mr. Moneyone.

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