I have an 08 528i and noticed a high pitch "squish" sound as I apply the brakes, it comes from the rear (both sides). Has anyone experience this? You can hear it when the two front windows are rolled down, not so noticeable with the windows up.

 

There are 2 reasons for this:
1) The pads are worn and they need replacing
2) The brakes are dirty. OEM brakes on our cars are VERY suseptible to dust, specifically brake dust. When the brakes get dusty they squeak and our cars tend to sound like an 87 Chevy Cavalier at that point. I took my car to the dealer a few times for this and each time they said brake sqeal was "normal". I opted to replace my pads with Hawk HPS pads (less dust) and be VERY liberal with grease when installing my pads - thanks to member 525iEnjoy - (obviously avoid getting grease on the face of the brake pads). This reduced dust significantly and elminated the sqealing that was driving me crazy.

 

Thanks for the suggestions.

Here's the odd thing, the pads have a half life left and the rotors probably about the same. I took both rotors off, cleaned all the brake dust and everything went back in clean... same "squish" sound, it's not a "squeal".

I'm replacing the rotors, pads and brake shoes next, hope it goes away, just thought I post this in case there's something else that I should be checking for.

 

Not really anything I can think of, the OEM brakes work really wel on our cars. However, the dust and noise levels leave a LOT to be desired

 

By the way, the reason why I'm changing the brake shoes is because of a "squeak" when the hand brake is on. If I sit on the passenger seat and rock the car a bit, which naturally happens when a passenger sits in your car, there's a squeak from the rear. I thought it was the rear shocks, but it coincides when the hand brake is on, the brake shoes are probably touching the back plate and squeaking, I'm using plenty of sound deadener paste when I install the new ones!

 

I have the same issue. I have even replaced stock brakes and rotors with EBC and replaced both sensors but the high pitched squeal is still there. I also took the sensors off and drove the car and it still squealed. Any suggestions?

 

Do you change your brake fluid on the two year cycle?

 

Thanks to all responses. On this annoying issue. Mine is now squeak free. After completing the proper brake bedding process I have had no further issues. Thanks again for helping me to not sound like a POS when pulling up to a stop light!!!!!!!