My car has a brake vibration that I have been trying to track down. What is this discoloration from? Overheating? The surface feels smoother than it looks. Or maybe it’s not as smooth as I think?
My Corolla’s brake rotors are pristine looking, very shiny metal. At least for the part that meets the brake pads. That looks like a problem of some sort has occurred, perhaps overheating due to long downhills? Been driving up to Pikes Peak a lot? lol … If the vehicles was parked a long time, could just be rust too. Is the rotor thickness in spec? What about the run-out?
The short answer is you need new rotors. Before replacing make sure the brake calipers release the rotors smoothly.
I didn’t see the pic first and was going to say it would be difficult to say if you need new rotors just based on the picture. But the rotors look so bad in the picture that now we can agree that you need new ones.
Change the pads and make sure the pins are moving fine and your pads are not dragging.
The dark areas are rusted spots with embedded pad material. These appear in spots because the moisture remains trapped longer between the pads and rotor. This is not an unusual sight, not a reason alone to replace the rotors but the combination or rust, pulsation and performing a brake job these should be replaced.
Well the good news is you found the vibration problem you get when you put your foot on the brake pedal. As another commentor said the grooves are from pad material and other dirt caught between pad and rotor, this is a very common reason that rotors wear out to the point where they can’t even be turned. The not so good news,those rotors are toast, they may be able to be turned if you want to do that, I’m inclined to think not. I worked in automotive for 30 years, I don’t think much of turning rotors because it removes metal and makes them more inclined to warp. That’s just my opinion, but I’d rather buy a pair of cheap rotors (it’s just a hunk of metal with holes in it, cheap rotors are very similar to OEM if you drive like an old fart as I do)., If you drive hard then I’d consider ventilated rotors (drilled full of holes when they are made for better cooling) if you want a real upgrade…note that these are what most police cars use.
Nobody would keep those rotors and you wouldn’t either. We know that. Those are just old and whenever there are grooves there is side to side shaking going on because the grooves, along with the wear, are uneven in depth.
Some rotors are even more ratty than those and still don’t cause shaky brakey. If those are just the front ones and you have rotors on the back, don’t forget to check them. My front rotors were worse than yours and the shaking was caused by the right rear.
I put on different rotors. pulsation is 95% gone. I have a few 55mph stoplight intersections on my way to work and it felt much better today.
Yup, nothing like maintenance to get the old buggy running better. I hope you checked out your brakepads and rotors while you had everything apart.
Don’t spend time looking at the worn area, look at the lip at the edge. That’s a lot of wear. I’m not at all surprised that new rotors and pads cured most of your problems.
Yeah, the lip didn’t look too bad. Did you caliper the thickness of the old rotor, out of curiosity? If I had those old rotors sitting on the bench in front of me, I wouldn’t be able to resist checking how thick they are… lol …