Rotor texture...?

[JP X]

I took this photo tonight from my son's 2019 rear rotor (non-PP). When I run my finger along it, it feels...for lack of a better description..."bubbly". It reminds me of when you have a chromed ice cream scoop get all bumpy. I've never seen this on my car. This rotor only has 7k miles on it. The car came from the NE. Any ideas?

 

[TMSBOSS]

Are the bubbles on or in the metal?
If it’s in, they are likely corroded.
If it’s on the rotor, it’s likely buildup of pad material.

 

[o-man]

looks like "corrosion" to me. Live with it if not too noisy or replace the pads and rotors

 

[JP X]

looks like "corrosion" to me. Live with it if not too noisy or replace the pads and rotors

I’m guessing corrosion. I suppose I didn’t need to ask, because I’d replace under either scenario. Rotors are inexpensive. That’s what I get for buying a NE car!

 

[RES_22]

Corrosion from unuse. Drive it awhile around town...lots of "assertive" stops on cold brakes. Oftentimes cleans up well.

 

[OPMustang Tim]

They would clean up on a brake lathe, that might cost more than just throwing on a set of cheap rotors. From sitting on a lot? The stock rear pads are not aggressive enough to machine the rotor clean again.
Usually NE winters cause all the problems on the inside of the rotor, where you cant see it and the car washes don't get to. The inside rotor edge begins to grow and de-laminate the rotor material.

 

[mavisky]

4 years old, 7,000 miles, lived in the northeast, definitely just corrosion from sitting around.

 

[Bill Pemberton]

As noted by others a new set of pads is quite reasonable and anymore getting them " turned " at a shop may cost as much as a new set with current labor rates. One other item you did not mention, but bears asking, is what do the pads look like?

The one item on the picture that looks odd to me is the numerous circular cut lines in the rotor ( at least it appears as such in the photo ).

Lastly, since it is the rears, just drive around yanking up the emergency brake numerous times and see if there is any improvement?

 

[JP X]

As noted by others a new set of pads is quite reasonable and anymore getting them " turned " at a shop may cost as much as a new set with current labor rates. One other item you did not mention, but bears asking, is what do the pads look like?

The one item on the picture that looks odd to me is the numerous circular cut lines in the rotor ( at least it appears as such in the photo ).

Lastly, since it is the rears, just drive around yanking up the emergency brake numerous times and see if there is any improvement?

Yeah, since rotors are cheap I’ll replace them and get good pads. The kids want to drive this car on track I’m going to upgrade anyway. Having grown up in SoCal and then living in NC for 22 years, I’m not familiar with corrosion. Thanks all for the advice!