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[e92-335i-9000miles] Squeaking during 0-10mph acceleration.

X E I O2010-08-17 16:54:47 +0000 #1
I don't trust dealers, but I trust the very well educated BMW maniacs here on this forum.

I've notices that around 0 - 10 mph, [e92-335i-9000miles] will present me with a squeak. This squeak is loud, loud enough to be heard with no music, no conversation, and windows closed, from the passenger side. I'm guessing it's coming from the front/passenger side wheel. Any guesses on the problem?

Thanks,

X E I O
roller842010-08-17 16:58:37 +0000 #2
It happens on my car as well. It is coming from the brakes. When I apply the brakes it goes away. Very annoying. I am supposed to ride around with the foreman at my dealership since they could not reproduce the problem on my last service visit. I'll let you know what they find.
CnoteMD2010-08-17 17:32:35 +0000 #3
I had something similar a while back. It was a faint squeaking sound that would only occur while driving very slow. It seemed to start after doing a lot of stop and go driving.

It was nearly impossible for the dealer to reproduce, so I had to take one of the techs on a 30 minute ride to illustrate the sound. They said they found rust in the wheel hub and replaced a few parts of the emergency brake and the problem was solved.

Hope that helps.
magmd2010-08-17 17:36:27 +0000 #4
Same problem. Squeaks when roll from a stop. Goes away with higher speed and when applying the brakes. Coming from right rear wheel. Dealer first said it was an ebrake issue and they said it was fixed. Then it was a brake sensor that needed to be replaced, and they cleaned out the brake pads...apparently there is alot of brake dust build up, along with some rust. This fixed the problem for about 2 weeks. Now the noise is back...not as loud, and not all of the time...but its there.

Apparently, everyone agrees that it has to do with the braking system and a car that is in constant stop and go traffic. I am not really sure how to remedy this problem....as the dealer has looked at it twice. Members on bimmerfest said that we need to clean out the brake assembly more often....so I guess I need to learn how to do this.

Here are the links to the discussions that I could remember

www.bimmerfest.com/f...wthread.php?t=186052

www.bimmerfest.com/f...wthread.php?t=187689
magmd2010-08-17 18:36:24 +0000 #5
This is one response I got from the thread above:

Pull the wheels. Remove the caliper lower bolt. Swing caliper out and up. Remove brake pads. Clean with spray brake cleaner. Spray everything associated with the caliper assembly. Take anti squeal shim and coat the side that is resting against the brake pad and coat it evenly with high temp silicon (RED STUFF) and place against pad. Do the same with the other pad. Place just a bit of High Temp silicon on the circumference of the caliper piston that rests against antisqueal shim. Let DRY. Then Assemble.

Now go out and see how much they squeal.

Here is the best explanation I got from the above thread...not sure if it is correct, but sounds likely:

Brake squeal comes from one source and one souce only, brake pads vibrating off the rotor. You fix that and you fixed the problem. Camphering the brakes pads is one solution to helping solve the problem and what ever tech did that was spot on if the edges were sharp on the pad causing the vibration. The reason the red silcon on the back of the pad works is that it helps to dampen the vibrations which in reality are still there. can you imagine BMW allowing a tech to put silicon on the backing side of the pads?

The other solution of cleaning the rotors and pads is a good one but in the case of your cars I think the reason it comes back is from yet another common problem with brakes. That problem is that the brakes transfer material to the rotors and when you have an uneven distribution of that tranferred material then you also get the vibration of the pads off the rotors which causes the squeal. zThat is usually caused by light braking over a long period of time. Anyone in stop and go traffic for long periods of time and doing light braking as you poke along?

One thing that might work which has worked for others at times is to do some aggressive braking. What you would be doing is making some fairly heavy braking at a good clip to help heat the brakes up and see if you can help this problem. It used to be called brake glazing but it really isn't. Just don't overheat your brakes and do this where you have no chance of someone rear ending you too.

You can break the brake pads in too gentley.

Usually BMW recommends replacing the rotors with the brake pads when the brake pad life is gone. That would solve the problem but would be expensive to an owner too if BMW doesn't cover that replacement. BMW recommends the rotors be replaced because the loss of material on the rotor will contribute to warped brake rotors which will piss off a driver even more then the squeal. New pads and turning the brake rotors down to remove the glaze is about the only solution. There maybe not sufficient thickness on the rotor to allow turning as well.

The problem you mention is not limited to BMW, my mates Toyota Avalon and my Ford Super Duty Diesel truck had warping issues after the dealer, in both cases "fixed" the problem and I had to correct it in less then 5K miles later.

I would bet the techs are truely working hard to fix your problem as indicated by both attempts having been correct things to do for some squeals but I would also bet BMW policy is to not replace rotors when it is on their nickle. If you can get the tech aside I would ask them about your rotors being glazed.
X E I O2010-08-17 18:22:05 +0000 #6
See, this is why I trust you guys.

Although I'm unlikely to clean out my brakes... I'll be less annoyed knowing its one of the possible brake issues above.

Lastly, What is the point of being able to start the machine without the key?

[Example]

Hold brake and push start button with key inserted.

Engine starts.

Push stop button.

Engine stops.

Push and pull key out.

Hold brake and push start button without key inserted.

Engine starts.

Was this a BMW mistake? I thought BMW doesn't make mistakes. There had to be a point to this. Did they build ComfortAccess into all these machines?
flipmde7862010-08-17 19:38:41 +0000 #7
I've been noticing these squeaks for a long time, maybe for at least the last 10k miles, but I thought maybe if I keep driving it'll go away. Of course, it didn't. So I finally decided to take it in to service.

They told me that this is a prominent problem and BMW is currently "working on a fix," but right now, there is no fix. The guy said my pads are totally fine, not wearing thin, and that the noise is the result of the compound used in the pads. When they heat up, the friction with the rotor causes the squeak noise or something.

He said BMW is trying different compounds to fix the problem and once there is a fix, I will be notified to bring the car back in. But for now, there is no fix, and they're not allowed to try anything else (like replacing pads/rotors, etc).
magmd2010-08-17 20:19:06 +0000 #8
I was told it was the caliper slides that stick.

Seems to help when they are cleaned out, but problems just keep coming back. BMW keeps saying its common with BMW cars, but it seems to be a REAL BIG problem with the E90's.

I am taking my car in for service next month..its the 30k mile service, and going to ask for oil change, new progman update, and to look at that squeak again.

I do hope they figure something out because the noise is really annoying!
pincud2010-08-17 20:25:17 +0000 #9
I have the same issue with my 335i. It can be heard after driving more than 10 miles, when the wheels and the brakes warm up. When I took it to the dealer to have the car diagnosed, they could not reproduce the noise because the car was still cold.

However, one day I drove it to the dealer straight from home, about 15 miles, and the wheels were noisy like a locomotive. The shop forman heard the noise and scheduled an appointment to fix it.

Their fix was to de-glaze the rotors. Glazing occurs when instead of slamming on the brakes at every light, you let the car cruise and then you gently apply the brakes. However, glazing only causes the brakes to squeal when you stop on the brakes. So, after deglazing the rotors and spraying them with Anti Squeal Spray, they gave me the car back. I should mention that the car was in the shop from Thursday morning until Monday afternoon.

When I picked up the car, the SA told me what they have done to fix it, and I laughed out loud. I knew that would not fix the issue, and by the time I got home that day the wheels were squealing again.

So, I got a little ticked and wrote a letter to the general manager and the SA about the problem and threatened to file a complaint with the Better Business Bureau and also talk to some TV channels and newspapers. The next day, the GM called me to let me know that he's looking into the issue.

He called a day later to let me know that he is ordering new calipers for the back wheels and install them later this week. Based on his research and discussion with BMW in Germany, he thinks that is the solution to the squeals and noises coming from the car when starting from a stop and up to 20 mph.

Replacing the calipers may or may not solve the noise issue. We shall see.

The car had around 6000 miles on it when the noise started, about 3 months ago. It now has 10,500 miles on it, and the noise is still around.
CnoteMD2010-08-17 21:34:09 +0000 #10
I just took my car in to have the brakes checked out (and got the iDrive software update) and got a similar response. They said that the brakes get "dirty" and start to squeak. Since I drove my car during the winter, they said there was also road-salt buildup which may have also contributed to the noise (though it was doing the same thing last spring/summer).

I have gone through the brake "cleaning" process 2 times in the 20 months I've owned my car, but it seems to only be a temporary fix. My brakes are still reporting about 10k miles remaining (already have 23k miles) and the sensors seem to be working fine.

I'll see how long it takes before the noise comes back. Hopefully, they will have a permanent fix by the time that happens.
pincud2010-08-17 21:38:31 +0000 #11
My car was in the shop on Friday, and the dealer replaced the back calipers. The wheels do not squeal anymore.

Maybe this will work for you as well.
magmd2010-08-17 21:43:11 +0000 #12
Quote:

Originally Posted by pincud

My car was in the shop on Friday, and the dealer replaced the back calipers. The wheels do not squeal anymore.

Maybe this will work for you as well.

Damn! I wish my dealer would just replace them as well. Seems like it will solve the problem. The issue....will it just come back in time??

That is kewel that your dealer did that....mine just seems to want to "clean" them out for a very temporary fix.

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