CCB Rotor Missing Chunk

[s0tawf02]

Hey all,

Just got my 2016 M3 with carbon-ceramic brakes and I'm mostly happy. It just came in last night and after driving it around a while I didn't hear any squeaking coming from the CCBs. I went to park it in the driveway which has a little lip to it and after it went over the lip there was the worst squealing noise I ever heard. Drove it again for a good hour or two today and no squeals. I took it in for an inspection and there's a good size chunk missing from the rotor. My shop doesn't see too many M3s with CCBs so he said since the pads look good, and the car feels normal upon braking that I should just monitor the rotor to see if it gets any worse. Also, the indicators look pretty good and the car is just under 45K miles. Thoughts?

[Wanted_M]

CCB criteria for spallation as per BMW:
Partial spalling of the friction layer has no influence on the function or safety of the brake system (no comfort disadvantages or uneven braking force distribution). The separation is a purely visual defect, but may cause customer disappointment and uncertainty. If the pitting/spalling reaches 2x2 mm, these ceramic brake discs can be replaced.

Criteria below;
https://f80.bimmerpost.com/forums/at...6&d=1429097850
https://f80.bimmerpost.com/forums/at...7&d=1429097850

[s0tawf02]

Originally Posted by Wanted_M

CCB criteria for spallation as per BMW:
Partial spalling of the friction layer has no influence on the function or safety of the brake system (no comfort disadvantages or uneven braking force distribution). The separation is a purely visual defect, but may cause customer disappointment and uncertainty. If the pitting/spalling reaches 2x2 mm, these ceramic brake discs can be replaced.

Criteria below;
https://f80.bimmerpost.com/forums/at...6&d=1429097850
https://f80.bimmerpost.com/forums/at...7&d=1429097850

Thanks for the information, but I think by "spalling" they mean the way that the rotors almost look cracked (see original pics for clarity). And then it says if pitting reaches 2x2 mm, these ceramic brake discs "can" be replaced. I know they CAN be replaced but do they NEED to be replaced? Thinking about this logically, I don't think this would lead to any catastrophic failures of any kind and since they're not effecting my braking (as far as I can tell) do they need to be replaced?



Hey

[Wanted_M]

Its a sub-surface defect that causes separation of the top layer of the CCB liner. You probably have seen concrete or stucco walls with the same spallation. The disk doesn't need to be replaced as they call it "cosmetic" but it can be if its 2x2 section (you can argue that point). According to the document it doesn't affect performance.

If its replaced the dealer has to send the rotor to Germany for inspection and reimbursement. I suggest you share the doc with your dealer/SA and reassess from there, I'm just trying to help you make the right decision as you have 45k on the odo and at 50k is bye bye warranty then you might be stuck with a large bill to cover if it does get worse.

[IVM3]

If you just bought this, and it's from a dealer and not under warranty, I would push the issue to have them replace it or partially reimburse you. I wouldn't be happy with a CCB rotor in that condition if I just bought the car.

[s0tawf02]

Originally Posted by Wanted_M

Its a sub-surface defect that causes separation of the top layer of the CCB liner. You probably have seen concrete or stucco walls with the same spallation. The disk doesn't need to be replaced as they call it "cosmetic" but it can be if its 2x2 section (you can argue that point). According to the document it doesn't affect performance.

If its replaced the dealer has to send the rotor to Germany for inspection and reimbursement. I suggest you share the doc with your dealer/SA and reassess from there, I'm just trying to help you make the right decision as you have 45k on the odo and at 50k is bye bye warranty then you might be stuck with a large bill to cover if it does get worse.

Ok, I see what you're saying now. Yea I think I'm just gonna monitor it and see if it gets any worse.

Originally Posted by IVM3

If you just bought this, and it's from a dealer and not under warranty, I would push the issue to have them replace it or partially reimburse you. I wouldn't be happy with a CCB rotor in that condition if I just bought the car.

Lol yea I ended up getting $2K back. I know it's a $4K rotor, but honestly if I ever replaced these I would just replace them with the M2C rotors and pads which would be under $2K so I'm ok with that.

[dubsesd]

looks to me like a continuous drag mark around the rotor face. im pretty sure you caught a stone that dragged around the entire rotor and ended up chipping the face in that location.

[s0tawf02]

Originally Posted by dubsesd

looks to me like a continuous drag mark around the rotor face. im pretty sure you caught a stone that dragged around the entire rotor and ended up chipping the face in that location.

that actually sounds like a pretty good explanation. I can't believe the rotor is that brittle.

[IVM3]

Originally Posted by s0tawf02

Ok, I see what you're saying now. Yea I think I'm just gonna monitor it and see if it gets any worse.



Lol yea I ended up getting $2K back. I know it's a $4K rotor, but honestly if I ever replaced these I would just replace them with the M2C rotors and pads which would be under $2K so I'm ok with that.

Great deal! That's exactly what I would do if I were in your shoes.

[dubsesd]

Originally Posted by s0tawf02

that actually sounds like a pretty good explanation. I can't believe the rotor is that brittle.

well its carbon ceramic, so it has different properties to steel. it looks like it actually held up really well until the rock shifted in pressed harder in that particular spot