Kuangmao

Rear passages side rotor has few scratches.
Only 2500 miles.
What cause this and what to do?

wrinkledpants

No idea what you're talking about without a photo. Rotors aren't supposed to be smooth like they are when they are brand new.

User 4221

I think he may be saying the rotor is not being swept by the pads. If this is the case, then the caliper is probably frozen in-place and needs to be rebuilt.

endless_corners

How does a rotor get frozen in place?

19psi

He said caliper and it's common for the pistons in calipers to freeze up.

bweSteve

Does the rotor only have 2500 miles, or the Cayenne? (I'm assuming this is a older Cayenne).
If they put new rotors on, but did not rebuild the calipers, then yea maybe it's got a frozen piston or two in the caliper.
Do you (OP) feel the vehicle pulling to one side when braking? or does it feel sluggish like it does not have full power (because it's braking all the time)?
Does it smell like burnt brake pad after you've driven for a while?

hahnmgh63

We're all speculating without pics. Year and model of Cayenne always help a little too.

endless_corners

Oops, I think I had some whiskey in my eyes.

Kuangmao

Kuangmao

Cayenne is 2500 miles

JAGMAN1

Looks normal. Sometimes a grain of sand or some rust getting scrubbed off the rotor will cause that. Nothing to worry about.

wrinkledpants

Normal. Your rotors, over time, well get small grooves in them. They'll never be perfectly smooth like they are when they're new.

Kuangmao

Thanks guy.

bweSteve

agree, this looks normal.

Circular grooves that run parallel to direction of spinning rotor are the most important to keep an eye on (circled in red below).

The horizontal scratches (colored blue below) that run outward are probably as JAGMAN said, sand or grit getting caught in between the pads & rotor.

Hope you're enjoying your new Cayenne!!
=Steve

Dilberto

If you're scrutinizing your rotors......you need to just go and drive it.