Grinding/Squealing Noise

[blacknj]

My i3 is about 1 month old and yesterday while driving and especially while using the regen I heard this horrible squealing noise. Imagine the sound your brakes make when they are worn but the sound level of a tractor trailer braking. Since I am close to the dealer I started driving there to drop and it off and while taking a turn at a good speed a heard a light thud/popping sound and the noise is gone. It has not come back since (50 miles). Any idea what it could have been? At first I thought it was rust or buildup on the brakes so I did use the real brakes a few times and that did not help.

 

[websterize]

Probably road detritus that fell out.

 

[jadnashuanh]

This can happen on any car, but also has been reported on the i3...a small stone or something similar gets caught between the splash shield and the brake disk. Usually, it falls out on its own. Note, though, that because, once you get good with the i3 and its regen capabilities, you don't use the brakes much if at all, and the rotors can develop a coating of rust, and when you do apply them, until that rust is scrubbed off, they can be a bit noisy.

 

[Mito]

I think the car settles the brakes up to remove corrosion. I find the pedal is higher and firmer during this initial phase of driving. I think it is using the wet weather pad settling feature to ready the brakes as the regen will not clear corrosion and could lead to an inefficient first use of the brakes if it were in an emergency.
See the post here
http://www.mybmwi3.com/forum/viewtopic.php?f=11&t=1572

 

[TOEd]

Had a similar experience. Small stone fell out of brake pad/rotor after a few km. Also had this happen on our Honda. More likely to occur on gravel roads in my experience. I wouldn't worry about it.

 

[user 3172]

As said, usually a small stone caught between the guard and the disc. They can clatter around if loose but usually jump out eventually. If they get jammed they squeal as you described. If it keeps squealing try alternately reversing and driving forward for a while which can jolt it free. If not it's wheel off and hopefully you can get at it to lever it out without any dismantling.

 

[klu]

I get a weird screeching noise when I start the car up that lasts about 2 seconds, and then it stops and disappears. But it happens each time I start the car up. Does anyone have any ideas as to what this could be? FWIW, my brake fluid check notification is on, could that possibly be it?

 

[jadnashuanh]

No idea on the screeching, I don't think that there are any belts, so it would likely be one motor; maybe the heater blower? Is this starting up the car, or starting it moving? If only while moving, that implies something in the propulsion, if when turning the car on, one of the few things that starts up with a motor then is either the heat pump, a/c compressor, power steering pump, or the blower motor.

BMW (and many other cars) require/suggest that you flush the brake fluid on a 2-year interval based on the date of manufacture (not the date of sale). It's probably time for that service. It should not be ignored. Brake fluid absorbs moisture even through the rubber hoses...this can lead to corrosion from the inside, and also affect braking performance if not serviced.