NVRANUF

I have just over 2000kms and I've experienced the same issue 3 times now.. totally random and can't seem to replicate it.

Noise seems to be on the passenger side and sounds like a scraping metallic sound.
The second time it happened I was in a Canadian Tire parking lot and several heads turned to look at the car... It's THAT LOUD!
2 guys actually came over asking 'what's wrong with your car?"

Very weird indeed!!

speed21

So far so good. Nearly 2000kms and nothing. If it is happening whilst the vehicle is moving and sounds to be coming from one side over the other then maybe it is the PTV/PSM activating out of turn, clamping the disc on one side for a prolonged period overheating the components? An electronic gremlin issue... Or maybe a small stone has lodged between the disc and caliper. Had that happen on my 997tt and boy did that make an alarming metallic scraping sound. It was so loud and alarming I had to stop the car. If you drive over roads with loose debris on the surface then it can happen. I can't see the problem as being within the diff itself or the oil bathed clutch packs.

NMM991

In all likelihood, this noise is caused by a small stone between the rotor and the inner dust shield. I have noticed it on all three cars I've owned with ceramic brakes. On the 991 TTS you cannot get to it without putting the car on a lift. Usually the stone wears down enough to be spun out of the dust shield. I have never had damage to the rotor, but it is concerning to be sure. Porsche dealers know all about this issue; but to my knowledge Porsche has not redesigned he dust shield to minimize the possibility of getting a stone caught between it and the rotor surface.

speed21

Maybe next time it happens, bring the car to a halt, select reverse and go back a bit, apply the brake on and off a few times, then go forward and if the noise is gone then you know it was just a small piece of foreign material lodged between the pad and rotor.

NVRANUF

Dust shield seems to be the most likely suggestion here, even though I don't have PCCB's. The tinny, scraping, scratchy metallic sound could be dust shield induced. Each of the 3 times I had it happen was on paved road or parking area...
Weird in that my GT3 never exhibited the same.... or maybe because it was so loud everywhere else I'd never have heard it! LOL

NMM991

While I was cleaning my car today, I realize that you can get at the dust shield from the outside of the wheel through the spokes. If you push on it you notice that it flexes ⅛ inch or so. Next you get the noise, try to push on the dust shield to create a little space between it and the rotor and see if anything drops out. It's an awful sound, probably sounds worse because of the amplification from the shield itself.

jwp98

My 2014 TTS has a rear end noise. At about 700 miles, I started hearing a chatter or quick kachunk. Not a squeak, though my high frequency hearing may be shot. It happens usually on 1-2 upshift or on decel. If you have heard a car like the GT2 RS, with a lightweight flywheel and drivetrain clatter, that is the sound. I figure things are just loosening up. Anyone else heard this?

cartester

If it happens when you brake then that's a known issue with the PCCB. Porsche will replace the rotors if they confirm that's the problem. Some here have reported it finally goes away on its own after a (long) while.

jlee504

Weird, I had a grinding noise yesterday in my TTS. It was at a low speed too, 20-25mph I was going down a local street when I heard a grinding like a can or marbles or something then it went away. It was 2-3 seconds.

Hasn't come back since, it felt like it was coming from the tranny but it could have been anything.

I'm hoping it's a stone in a dust shield, that seems pretty plausible.

Jeff

NMM991

Most likely these noises which can range from sounds like marbles rotating in a can to a squealing/scraping sound as described above, are caused by a stone or pebble lodged between the rotor and the dust shield on the inside of the rotor - there is somewhere between ⅛ and ¼ space where pebbles picked up by soft tires and spun into this gap. The resulting sounds are quite ominous - I have experienced it on both my 1,700 mile 991 TTS and my 30,000 mile Cayenne TT, both with ceramic rotors (which probably amplify the noise). Porsche techs have confirmed this possibility to me - they have removed stones that customers bring into the service department.

From the outside of the wheel, you can push the dust shield slightly away from the rotor, increasing the gap, and any stones/pebbles in there may fall out - these stones rotate around the rotor so you have to know where the stone is but if it is on the lower half, it will usually drop out. At high speeds, I believe either the stone is ground down or is flung out of the gap. Really annoying - hopefully this does not cause any damage to the ceramic rotors, my tech told me that he has not seen that situation.

Overdraft

Mine yesterday...600 KM on it. Will keep an eye on it. btw....still love my car.

NVRANUF

It's happened a few more times now.
Aside from being a little embarrassing when there are people around like last time in the paddock area at CMP after coming off the track and the time in the CT parking lot described above... It's definitely that loud.... I just ignore it.

Trimmer

I haven't heard anything remotely like what anyone is describing.....yet.

sdg1871

I have had the sound several times. Each time it was caused by pebble gettingn lodged between the rotor the brake shield. It's extremely annoying.

GrandLaker

I've had it a few times too on the road by my house. Lots of loose chat and these tires are so sticky it constantly flings the small rocks and on occasion they get caught. Only lasts a few seconds and falls out apparently. It does get your attention however.