Squealing sound when braking

[MightyMouseTech]

Originally Posted by 135iWashDC

I believe this to be some kind of manufacturing defect, and as it's with the braking (i.e., something directly involved with safety of the vehicle), and not all 135i's seem to have it, that's a bit concerning re: BMW's quality and safety system checks.

It is just a noise, it has zero to do with safety. Even BMW says it is normal. Drive harder.

[tommyb13662]

I actually have a very cheap organic (non metalic) set of pads for street driving. Very soft pad. A bit less dust. Never have any noise from these. However searching online cant seem to find them anymore and they are due for replacement. Knew i should have bought more than one set. The stoptech (slotted) rotors eat these pads in 15-20k. The OEM/aftermarket semi metalics would squeal very often. Also had this squeal from a set of ceramic pads.

[jlc45]

I am pretty knowledgeable about brakes but I am new to BMW.
I have been doing my brakes on all my vehicles including light trucks for the last 35 years. I have never had a problem with brake squeal. (Sh*t, I just jinxed myself!)
Brake squeal means something is vibrating at a high frequency.
It is very important that the pads (no matter what kind you use) must be able to move without binding in the calipers or in their brackets (depending what type you have).
Quite often new pads do not fit properly. You have to make sure they can move "in and out" - in when the pistons push them against the rotors, and out when the pressure is removed. If they are cocked in their holders, or in the calipers on a 135i, they will wear down at an angle, they will make too much dust, and they may chatter or squeal. If this is not the case with a serious squealer, it's unlikely, but you could have cracks in the rotor(s).
Jim

[jlc45]

It is not "normal" to have braking noises if the system has been properly maintained.
When someone says there is nothing you can do about it, it means he does not really know how they work. I bought my cpo 135i in Oct. The brakes had been done by the dealer including new rotors, in the summer. I took them all apart immediately. The rotors were already slightly seized on the hubs. The pads were all dirty and sticky.
If you maintain them properly and drive sensibly brake pads and rotors will last a long time. (I'm not talking about track cars here.)
Jim