Tin Can / Bottom Scraping Noise

[Gstone]

Or maybe they can replace it with a better solution.
Such a widespread issue, does anyone know if they are aware of this?

[IB M]

Too bad a lack of pride in our communities and municipal budget deficits have resulted in the demise of the street sweeper. Where is that truly unsung hero when we need him most?

[Powerslide]

Originally Posted by P-TownM3

I'm not buying that explanation. No way little pebbles stuck around a brake shield could make the very loud metal on metal grinding sound that I heard.

I definitely agree - reason being is I had pebbles stuck in my brake rotors (which never went away, regardless of speed, until I took the car in and had the pebbles removed).

At the same time I had the above noise, I would occasionally hear the tin can scraping sound which would happen only once every week to two weeks, and was not reproduceable.

Now - about a month after the pebbles have been removed, that particular sound has never come back. On the other hand, that occasional tin scraping sound still happens about once every 2 weeks (or about once every 500 miles or so) - it only happens at very low speed - 1st or 2nd gear - and it lasts only about a fraction of a second and is gone - if this were a pebble it would repeat and it would increase in frequency as speed gets higher and decrease in frequency as speed drops (which it clearly does not).

My guess is that the sound is coming from the rear diff (service dept. could not reproduce the noise - but they easily reproduced the pebble noise before removing the pebble, and once the pebble was removed, that particular noise never came back...

[slalomfever]

so apparently there was a discussion (roundtable) about this with the technicians from the dealerships. The metal noise is coming from the e-brake cable hitting a shield during acceleration. The solution is to push the shield away from the cable....That's it. Funny how BMW AG engineers didn't hear this at all during R & D.... seems like a very simple solution. My car is at service today for this "fix"...Hopefully, the noise goes away.

[NorCal f80]

Originally Posted by slalomfever

The metal noise is coming from the e-brake cable hitting a shield during acceleration. The solution is to push the shield away from the cable....That's it.

What about the other noise, the one that occurs at 3-5mph?

[slalomfever]

Originally Posted by dwin_sd

What about the other noise, the one that occurs at 3-5mph?

not sure...I'll keep you guys posted on my car after I get it back

[Vigilant]

Originally Posted by slalomfever

not sure...I'll keep you guys posted on my car after I get it back

I have not experienced the tin can noise since the break in service.
Please let us know what you find after your service.

[baalzephon]

I had something similar happen - a HORRIBLE metal-on-metal grinding sound coming from the front left wheel that would "speed up" as the car was driven faster. It eventually shook off after driving for 20-30 miles but it was horrendous. I happened to be going to the dealer anyway and they took a look and found nothing. Interested in what people hear in case this happens again.

[slalomfever]

so I got the car back after working with a BMW technician on finding the source of these weird noises. We removed the exhaust and all the metal covers that surround the e-brake cable and drive shaft. There was no visible wear or indication that the drive shaft was hitting the e-brake cable as the service bulletin had stated.

We put all the parts back and tightened everything but the noise came back after driving for a few minutes later.

Honestly, its annoying and very frustrating.

PLEASE...if anyone has an idea on this "metallic" noise coming from the rear...chime in!

[jbtco]

I had the low speed tin can rattle which only lasted a few seconds quite a few times in the first several hundred miles ( loud enough to make pedestrians turn round to see where the noise was coming from) but haven't noticed it recently. Now done a little under 4,000 miles on the same roads so can't see how it can be pebbles or it would be happening again.

I wonder about the theory that it is slight corrosion in the handbrake mechanism as I now regularly apply the handbrake briefly as moving off (as recommended in the user guide).

[serieD]

Originally Posted by Powerslide

I'm at about 3800 miles - I hear it less often than before the 1200 mile service, but it still happens occasionally when starting out from a stop in 1st or 2nd gear (DCT).

I've already tracked my car - performed like a rock star. That occasional noise only happens maybe 1-2 times per week (daily driver). As long as I continue to have warranty coverage and as long as car continues to drive great (which it does) then I'm not going to worry and let it ruin my enjoyment of the car...

I am right there with you. I have 3700, tracked the car, and the noise happens sometimes. But i will say it has significantly decreased.

[Buddy Revell]

I've heard this sound twice in the first month I owned it. Haven't heard it since. Good to know it wasn't anything major.

[AMPowerJ]

Mine seems to happen when applying the brakes FWIW. One day if we all keep at it someone will solve this.

[Needsdecaf]

What did this noise sound like? And when do you guys hear it?

Have a specific situation, want to see if it's the same as what you guys are experiencing...

[Mandi90TT]

It usually happens after I've been parked, and back up from a parking spot, after releasing the handbrake. However, it has happened in other situations, varied ones.

It sounds like a can scraping on the ground.

[secretariat]

I mentioned it on my first post, it sounds like driving over plastic bottles for about 5-7 seconds. (I stopped using emergency brake for this reason and haven't really heard it since) Also there is a grinding noise like metal on metal when making slow left or right hand turns. A lot people say this is due to a pebble stuck in the wheel well near or in the aluminum plate inside the wheel. But not sure about this?

[solstice]

I don't have the plastic bottle noise but I have the quick grind. About 1-2s high pitched grind, slow speed always from the rear right side. I had it 3 times yesterday always shortly after starting a drive and only once per drive. Doubt it's a pebble or rust on the brakes. Not concerned enough to take it to the dealer at this point.

Btw my check engine light seems to be permanently gone. Looks like the engine just needed to adjust to US gas.

[slalomfever]

definitely not a pebble....I have a friend with a pebble stuck in the brakes and the sound was more constant.

So far, this is only happening to the people with F80's that I know. I've been in 3 different cars and they all experience it.

[Needsdecaf]

Originally Posted by solstice

I don't have the plastic bottle noise but I have the quick grind. About 1-2s high pitched grind, slow speed always from the rear right side. I had it 3 times yesterday always shortly after starting a drive and only once per drive. Doubt it's a pebble or rust on the brakes. Not concerned enough to take it to the dealer at this point.

Btw my check engine light seems to be permanently gone. Looks like the engine just needed to adjust to US gas.

To me, this sounds like an ABS self check. I've owned two cars that did this. It always happened at, IIRC, 20kph, and was a grinding / knocking noise that lasted about a second or two.

[solstice]

Originally Posted by Needsdecaf

To me, this sounds like an ABS self check. I've owned two cars that did this. It always happened at, IIRC, 20kph, and was a grinding / knocking noise that lasted about a second or two.

Could very well be.

[Needsdecaf]

The other reason I ask is that on Monday, I attended the Ultimate Driving Experience here in Houston, and watched 6 M3's pound out lap after hot lap. Through one of the tight corners, there was almost a ratcheting / fast ticking sound. I asked the instructor if that was MDM at work and he said yes, but I never saw a flashing triangle. Not sure if it was the diff, or the traction control or something else. But it was there, on all 6 cars, at that corner every time.

Usually when I hear traction / stability control, it sounds like ABS intervention, which is a louder and slower tone. Almost a crack, crack, crack. This sound was softer and faster.

[solstice]

Originally Posted by Needsdecaf

The other reason I ask is that on Monday, I attended the Ultimate Driving Experience here in Houston, and watched 6 M3's pound out lap after hot lap. Through one of the tight corners, there was almost a ratcheting / fast ticking sound. I asked the instructor if that was MDM at work and he said yes, but I never saw a flashing triangle. Not sure if it was the diff, or the traction control or something else. But it was there, on all 6 cars, at that corner every time.

Usually when I hear traction / stability control, it sounds like ABS intervention, which is a louder and slower tone. Almost a crack, crack, crack. This sound was softer and faster.

Yes, it's rather high pitched, very different from normal ABS sounds. I first thought it was DSC since the first time it was during hard acceleration on a bumpy road but now I heard it during slow down and very mild acceleration. It's more like a fast spinning cog grind or a shield touching something relatively fast spinning. I can't place it with common sounds. At the very first I thought it was tire rub with the fender but no sign of that.