Squeaky brake wear sensors?

grunyon · 08-11-2013, 01:48 PM

Hello,

I suspect that I have squeaky brake wear sensors. My brakes have always been squeaky but if I rode them hard they would be silent again for a few hundred miles. The other day I was driving down my driveway and coming from my front driver's side suddenly there was a sound like something flipped up and got stuck in the brake mechanism but after about 50 feet of driving it corrected it's self. Ever since then, I get a painful-to-listen-to squeal that seems to be very loosely linked to whenever I brake. It definitely happens during braking but then sometimes hangs around for a few seconds after I lift off the brake pedal. It can also sometimes be casually heard at low speeds, and also sometimes heard mid corner.

I took the tire off and visually inspected the brakes but I found nothing suspicious looking. I used an air gun to try to blow anything out that I could. The noise was still there.

On some rare occacions when driving in a straight line at very slow speeds, I can hear a slight squeak from my passenger rear tire as well.

I know these two wheels are where the brake wear sensors are. They aren't supposed to make noise when the brakes are low or anything right? They're just supposed to set off a dash light? Is there anything I can do to shut the sensors up? Where can I find out how they are installed and removed? Maybe I could coat them with that stuff that's meant to fix squeaky brakes?

Thanks for any suggestions.

e36addict · 08-11-2013, 07:15 PM

If the brakes are worn to the point that the sensor is contacting the rotor, they can get very noisy. There is a bulletin out for this issue on all models. Pretty much the only fix for it is to replace the pads, rotors and sensor. Depending of course on the thickness of the rotors you may be able to get away with just pad replacement. Brake squeal is extremely hard to get rid of on these cars.. Either I'm lucky or I drive hard enough that I don't have any noise. On my mothers 135 I have tried everything to resolve the issue but I just can't make it stop.. good luck!

WPG D33Z · 08-12-2013, 10:29 AM

I just removed my sensors on the weekend and my car is silent now! I had about 30-40% left on the pads and the sensor did look like it was rubbing. Mine would only make noise right before coming to a stop.

1911A145 · 08-12-2013, 12:18 PM

Quote:

Originally Posted by WPG D33Z

I just removed my sensors on the weekend and my car is silent now! I had about 30-40% left on the pads and the sensor did look like it was rubbing. Mine would only make noise right before coming to a stop.

So... you just took them out and didnt replace them? Any lights on the dash or anything alerting you that the sensors are not in or the brakes are due?

grunyon · 08-12-2013, 06:59 PM

Please do tell. I might remove mine.

WPG D33Z · 08-19-2013, 11:48 AM

Quote:

Originally Posted by 1911A145

So... you just took them out and didnt replace them? Any lights on the dash or anything alerting you that the sensors are not in or the brakes are due?

That is correct, no lights or warnings. Lights will only go off if the sensor has worn through. My rear sensor wasn't even installed, looks like it was missed at the factory!

trajan98 · 08-09-2021, 07:56 PM

I did same thing as WPG D33Z removed the sensor on the front driver side. It was the only wheel making the squeaking noise. Brake pad was still over 50% so once I saw the information posted here I decided to remove the sensor. The sensor actually broke off when I tried to remove it. It was rusted and corroded..I had to hammer it out once I took the brake pads off. Just thought I would pass that along as the squeaking was driving me nuts! Thanks for all the info here.

08-11-2013, 01:48 PM	#1
grunyon Enlisted Member 16 Rep 36 Posts Drives: 2008 BMW 135i Join Date: Apr 2012 Location: Flemington, NJ iTrader: (1)	Squeaky brake wear sensors? Hello, I suspect that I have squeaky brake wear sensors. My brakes have always been squeaky but if I rode them hard they would be silent again for a few hundred miles. The other day I was driving down my driveway and coming from my front driver's side suddenly there was a sound like something flipped up and got stuck in the brake mechanism but after about 50 feet of driving it corrected it's self. Ever since then, I get a painful-to-listen-to squeal that seems to be very loosely linked to whenever I brake. It definitely happens during braking but then sometimes hangs around for a few seconds after I lift off the brake pedal. It can also sometimes be casually heard at low speeds, and also sometimes heard mid corner. I took the tire off and visually inspected the brakes but I found nothing suspicious looking. I used an air gun to try to blow anything out that I could. The noise was still there. On some rare occacions when driving in a straight line at very slow speeds, I can hear a slight squeak from my passenger rear tire as well. I know these two wheels are where the brake wear sensors are. They aren't supposed to make noise when the brakes are low or anything right? They're just supposed to set off a dash light? Is there anything I can do to shut the sensors up? Where can I find out how they are installed and removed? Maybe I could coat them with that stuff that's meant to fix squeaky brakes? Thanks for any suggestions.
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08-11-2013, 07:15 PM	#2
e36addict Captain 137 Rep 952 Posts Drives: 2013 X1 35iX Join Date: Jul 2013 Location: Tim @ BMW of Dallas iTrader: (5)	If the brakes are worn to the point that the sensor is contacting the rotor, they can get very noisy. There is a bulletin out for this issue on all models. Pretty much the only fix for it is to replace the pads, rotors and sensor. Depending of course on the thickness of the rotors you may be able to get away with just pad replacement. Brake squeal is extremely hard to get rid of on these cars.. Either I'm lucky or I drive hard enough that I don't have any noise. On my mothers 135 I have tried everything to resolve the issue but I just can't make it stop.. good luck! __________________ 13 X1 35iX, 98 Z3 2.8, 01 M Coupe, 96 Z3 1.9 DASC, 95 318ti, 13 smart fortwo
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08-12-2013, 10:29 AM	#3
WPG D33Z First Lieutenant 23 Rep 316 Posts Drives: 2008 135i vert Cobb Stage2 Join Date: Mar 2012 Location: Winnipeg, Canada iTrader: (1)	I just removed my sensors on the weekend and my car is silent now! I had about 30-40% left on the pads and the sensor did look like it was rubbing. Mine would only make noise right before coming to a stop. __________________ 2008 SGM 135i Cobb Stage 2 FBO 2008 TS X3 MSport KW V2
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08-12-2013, 06:59 PM	#5
grunyon Enlisted Member 16 Rep 36 Posts Drives: 2008 BMW 135i Join Date: Apr 2012 Location: Flemington, NJ iTrader: (1)	Please do tell. I might remove mine.
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08-09-2021, 07:56 PM	#7
trajan98 Registered 0 Rep 1 Posts Drives: BMW 135i Join Date: Aug 2021 Location: Canada iTrader: (0)	I did same thing as WPG D33Z removed the sensor on the front driver side. It was the only wheel making the squeaking noise. Brake pad was still over 50% so once I saw the information posted here I decided to remove the sensor. The sensor actually broke off when I tried to remove it. It was rusted and corroded..I had to hammer it out once I took the brake pads off. Just thought I would pass that along as the squeaking was driving me nuts! Thanks for all the info here.
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