2014 RS5 Carbon Ceramic Brake Noise. Help!!

[Reesta]

Hi,
So I have a super annoying problem I cannot solve for months on my RS5. After a stop, when I let go of the brake it makes this soft metal grinding sound from the driver side front as shown in the videos (link below). And noise disappears when I apply the brake. So I think it's a problem with my carbon ceramic brake. I checked the pads, rotor, caliper, dust shield, and everything seems okay. I even got new pads and new pin/spring/clip for the caliper. I've tried audi dealership and two other performance shops, they can't figure it out. Has anybody had the same problem with their cars and know what could be causing this noise?

https://www.youtube.com/watch?v=G9yG5oy91ds
https://www.youtube.com/watch?v=b-EMIQ-kDtU
https://www.youtube.com/watch?v=judSINanq1c

Thanks!

[JamesRS5]

Carbon Ceramics require a transfer of pad material onto the rotors for them to work correctly (the opposite of regular cast brakes). The noise sounds like there’s an area of rotor that isn’t the same as the rest, I would suggest running the bedding in process again to ensure an even pad material transfer to the rotor surface and see how it sounds once you’re all bedded in again.


I can’t find the Audi procedure but they are all the same and usually made by Brembo, here’s an identical one that should have them bedded correctly, you’ve got to get heat into them to have the pad transfer and you need to let them cool with very little braking, look for an even glossy finish on the rotors when you’re done:

https://mbworld.org/forums/attachmen...structions.pdf

[Reesta]

- - - Updated - - -

Carbon Ceramics require a transfer of pad material onto the rotors for them to work correctly (the opposite of regular cast brakes). The noise sounds like there’s an area of rotor that isn’t the same as the rest, I would suggest running the bedding in process again to ensure an even pad material transfer to the rotor surface and see how it sounds once you’re all bedded in again.


I can’t find the Audi procedure but they are all the same and usually made by Brembo, here’s an identical one that should have them bedded correctly, you’ve got to get heat into them to have the pad transfer and you need to let them cool with very little braking, look for an even glossy finish on the rotors when you’re done:

https://mbworld.org/forums/attachmen...structions.pdf

I did "bed in" the new pads, but didn't do this complete process because it's hard to find a road to do this. Just a several hard brakes. But it was making the same noise before I got the new pads.
But I guess it wouldn't hurt to do the bedding in process again.

[Ape Factory]

I have ceramics as well and I can barely hear the noise in the video but I hear it best in the first one. I'm not hearing a grinding noise but I'm half deaf. I hear a squeaking noise. I can get a slight squeaking or squeal noise with light pedal application. I can't say, 100% if it's front or rear but it's definitely on the right side of the car. So if I'm approaching a stop, and I let up off the brake pedal slightly, I'll get a bit of brake squeak. Same if I'm crawling around in traffic. If I press ever so slightly harder, it'll go away. James, didn't you have a similar issue with squeal? Can't remember how you solved it off the top of my head.

Did someone at the dealership acknowledge they heard the same noise?

Now if I'm hearing you right, you're getting the noise while releasing the pedal. Is this a full release of the brake pedal or a gradual release similar to what I wrote above? Usually squeal is caused by the pad shims vibrating against the piston face or the back of the brake pad. It's solved with anti-squeal compound on both sides of the shim.

This is the official Audi break-in procedure for ceramic disks.
Break-in instructions
After replacing ceramic brake discs and/or brake pads, the following break-in instructions must be performed:
Pad new, brake disc new
10 braking aplications from approx. 50 mph to approx. 20 mph at a low rate of deceleration (corresponds to a
cautious, anticipatory style of driving, characterized by early braking, no apparent dive motion of the vehicle
under braking, no locking of the seat belt)
20 braking operations from 60 mph to approx. 30 mph at a medium rate of deceleration (gentle dive motion of
the vehicle is noticeable)
Follow-up braking must be avoided.
Allow the brakes to cool down between individual braking operations.
Trip time: approx. 30 minutes

Pad new, brake disc used
5 braking aplications from approx. 50 mph to approx. 20 mph at a low rate of deceleration (corresponds to a
cautious, anticipatory style of driving, characterized by early braking, no apparent dive motion of the vehicle
under braking, no locking of the seat belt)
10 braking operations from 60 mph to approx. 30 mph at a medium rate of deceleration (gentle dive motion of
the vehicle is noticeable)
Follow-up braking must be avoided.
Allow the brake to cool down between individual braking operations.
Trip time: approx. 20 minutes

[shonseb]

https://www.audizine.com/forum/showt...ht=rs5+ceramic

Although your issue sounds different from what I had. Mine occurred only during braking, not when letting off the brake.
I still get the metal grinding sound every now and then but I do short bedding in process similar to what Ape posted and it goes away.

[Ape Factory]

Good info! Reesta, I'd try to find a suitable location (like an industrial park early on a Sunday morning) and bed the pads in again.

[Reesta]

Hey Ape thanks for the input and sharing the bedding in process.

I only get the noise at a full release of the brake. And noise goes away if i apply the brake even a little bit. Weird.

[Reesta]

Good info! Reesta, I'd try to find a suitable location (like an industrial park early on a Sunday morning) and bed the pads in again.

Yea I'll try bedding in again. I don't get the noise all the time so it's so hard to diagnose. And it seems to happen after driving the car for a bit, so when the brakes are heated up. Maybe the pads expend and there isn't enough tolerance between the pads and those four guide pin thingys on the caliper that hold the pads? Idk. Or those pins got some dust build ups and dont let the pads slide freely? Idk man idk haha

[Ape Factory]

Maybe...or they attached springs incorrectly.

[JamesRS5]

It’s a rhythmic sound so an area of the rotor/disc is having different contact/friction properties with the pad than the rest of the rotor, you can’t warp a CCB rotor so you’re left with rotor surface problems caused by external factors or uneven pad material transfer.

Do you sit with your foot on the brake in traffic or at the lights? Holding your foot on the brake with hot rotors will make an area with greater pad transfer so making an uneven friction surface. The bedding in procedure will clear that.

Have you cleaned the wheels either yourself or at a car wash where they could have used harsh cleaning chemicals? Some of the stronger cleaners used by car washes for fast results can etch the surface of CCB’s so be aware of what they are using.

Do you (or a car wash) spray silicone based tire shine on the rubber, again, this should be avoided.

[Reesta]

Maybe...or they attached springs incorrectly.

Would the placement of the springs make a noise? You know the one end of the spring that hooks on to the pin? My springs are inside of the pads, but I see some pictures online and their springs are outside the pads, like between the pad and the caliper. My mechanic says his way is right so idk. Where did you place yours?

Sent from my SM-G950N using Audizine mobile app

[Reesta]

It’s a rhythmic sound so an area of the rotor/disc is having different contact/friction properties with the pad than the rest of the rotor, you can’t warp a CCB rotor so you’re left with rotor surface problems caused by external factors or uneven pad material transfer.

Do you sit with your foot on the brake in traffic or at the lights? Holding your foot on the brake with hot rotors will make an area with greater pad transfer so making an uneven friction surface. The bedding in procedure will clear that.

Have you cleaned the wheels either yourself or at a car wash where they could have used harsh cleaning chemicals? Some of the stronger cleaners used by car washes for fast results can etch the surface of CCB’s so be aware of what they are using.

Do you (or a car wash) spray silicone based tire shine on the rubber, again, this should be avoided.

I get my car cleaned at this place where all the supercars go, but I don't know what they use. I just assume that they use top grade stuff since they deal with supercars. I'll ask what they use.

Sent from my SM-G950N using Audizine mobile app

[ssaa77]

I’m curious if anyone found resolution on this. I’ve been having the exact same sound on my brakes. Not when I apply them but more after starting from a stop. So exact same symptoms as the OP. Well, it’s comforting to know that other people have similar issues. It is still pretty annoying. Still trying to figure out if I want to continue to deal with it or not.

[Ape Factory]

Might not be the brakes. How many miles on the car and have you had a shop look over the car yet? Could be your CV's or hub making the noise and not the brakes.

[ssaa77]

Yep checked everything. Dealership even replaced one of the calipers thinking that might be it. Everything checks out - dealership says it’s just what comes with ceramic brakes.