I have one rear rotor that is partially rusted on the braking surface and the rust won't go away. I tried scraping down the surface to even it out, and then the entire surface looked rusted. I had hoped that the pads would wear away the rust to expose the braking surface underneath, but only part of the rust wore away. I took pictures of the right rear pad before and after the scraping down, and also what the left one looks like for comparison. It seems like there is still a good deal of life left on the left rotor and also the pad, so I don't want to prematurely replace them if I can still get a good amount of use out of them. I am wondering if replacing just the right rotor would be alright, or if it looks like I'll have to replace the left side rotor/pads soon anyway and I should just do both rotors at the same time (and also do the pads while I'm at it). I have attached the following photos:
- Right rear rotor before scraping
Left rear rotor
- Left rear pad
Edit: my car is a 2007 Mazda 3 GT 2.3L
Edit 2: After I scraped the rotor, I tried using just the hand brake to stop to scrape more of the rust, and the brakes would kind of pulsate, as if the pad was partially catching on some parts of the rotor only. It eventually started doing this when I use all four brakes and get close to stopping, but it's much more pronounced when using just the rear brakes.