Boostman76

Anyone experience cracked rear rotors on C450? Ive seen hairline cracks on drilled rotors but shocked to see cracks on solid stock rears.

TModelle

Share some pics.

Boostman76

zibby43

Is that a crack or just a line where the brake pad was resting on the rotor and got a little rusty?

I can’t tell from the pic, but I’ve seen these lines on rears before and it was from what I mentioned above.

Mr. J

Jam your camera in there and see if you can get a cross-sectional view. If it's actually cracked, you might be able to get the rotor warrantied as that would definitely be a casting defect.

zibby43

When I look at the first photo, I can see a second faint line. The two lines are about the same width as the rear brake pad.

I would get similar lines on my 2018's rear rotors after washing my car.

TModelle

Haha that’s no crack! You’re all good, don’t worry about it.

Boostman76

Definately not cracked through....just on surface. Can feel it with my finger nail. If it was reminants/rust of rear brakepad settlement wouldnt it scrub off after a few minutes of driving and applying the brakes?

Mr. J

Yes.

zibby43

Not necessarily.

May take a few hundred miles.

I bought my now departed ‘18 C43 off the lot. It had been sitting out during a hot, humid, and super rainy early summer.

This is how my rear rotors looked after 500 miles of me actively trying to eliminate the baked on surface rust:





For whatever reason, rust really sticks hard to these rotors if you expose them to a lot of moisture.

jonathan358

I get those lines all the time, it's no problem.