Just got my new 911S cab a week ago and have about 300 miles on it so far. Over the past two days, I've noticed a fairly loud noise when braking. It's much higher pitch than a hum, and much lower pitch than squealing, and is only happening less than 5% of the time.

I'll take it to the dealer, but this could be one of those things they can't replicate, so any ideas regarding the possible cause and its seriousness? Maybe just part of the normal brake-in process for the brakes?

 

Brake squeal is normal and it's a common post topic. https://www.6speedonline.com/forums/...-city-bus.html

 

Thanks for the reply, but as mentioned in my original post, the sound is NOT brake squeal, since the pitch is several octaves lower. I wouldn't be concerned about it if it was just squeal, whereas this is a sound I've never heard before.

 

have you bed the brakes? at 300 miles they are probably most of the way there already but it couldn't hurt. you can search the board for specific instructions but basically you do 10 hard stops from 60-10mph then cool the brakes

 

Is happens only 1 out of 20 times you brake? Is it when the brakes are cold?

Or is it random?

 

As far as I can tell, it's random. No correlation I can discern with brake temp, braking force, car speed, or road steepness.

And yes, happening less than 5% of the time, starting yesterday. I could wait a while to see how it goes, since maybe a pattern will develop or it will go away, but don't want to harm the car. Fortunately, I don't see any reduction in braking force so far, so I'm assuming the car is safe to drive.

 

does it sound like metal scraping? or more like vibration induced?

 

Just wanted to post a little update on this. I just got back from a week of vacation during which the car wasn't driven. Today, we drove the car about 100 miles, and there was no unusual brake noise at all. So I'm hoping that the issue was normal and is gone now, but I'll keep an ear out for recurrence.

 

Let's hope it a thing of the past.

Good luck.

 

Just wanted to post an update in case anyone else has been experiencing this problem. The noise/vibration has been coming and going for a year, sometimes going away for weeks or even months, but recently it came back a lot one day, so I had the dealer check it out. They were able to replicate the problem, and diagnosed it as a problem with a "silencer" at the front brake pads. They'll be replacing some parts tomorrow and hopefully that will take care of it.

 

Sounds like a simple fix. I hope it works for you.

 

Turns out that the noise is still there, and still intermittent. Some days not there at all, some days you hear it once or twice, other days it's several times.

Has anyone else experienced this? Any idea what the cause might be?

It's frustrating because if I take it to a different dealer, they might not even hear it, so I'll just be wasting time. And if the sound happens at the track, they might not let me drive the car anymore out of safety concern (which would be understandable).

 

I had a car (not a porsche) in the past which made random noise from the brake. Took me 2.5 years with repeated visits to my dealer and still they couldn't fix the problem. They replaced many things like pads, lines, calipers; and the noise wouldn't go away. I was so frustrated I ended buying myself new rotors and the noise never happened. It took me more than 12 visits to the dealership and they couldn't (or they didn't want to) fix the problem. At a point I mentioned to them maybe changing the rotors would help and the guy at service department told me it was not necessary. Anyways, that was really the only car I had with brake noise issue and a brand I would never buy again. Not sure if this can help you but might worth a try. Hope you get the problem solved soon as they really ruins the driving experience.