Do I need to replace my rotors?

Question

I just bought my used 2015 nissan altima 3 months ago with 33k miles. My lack of knowledge with cars may be catching up to me as I'm now realizing just exactly how rusted my rotors are, basically completely orange. All 4 look roughly the same. I drive it about 10 mins 4 to 5 times a week to and from the gym and then occasionally on the weekends. Are these as bad as I think? Do I need to get all 4 replaced? I feel like an idiot for not bringing this up to the dealer before I bought it. Any help would be greatly appreciated.

Answer 1

While I cannot see the back rotors very well, I can tell you without a doubt, the front rotors are brand new. You can still see the crosshatching on the surface which means it was prepped. It doesn't show any wear at all. The rear brakes (from what I can see) are in good condition as well, though appear to be a bit older and more used.

The misconception you have here is you are basing the wear of rotor on non-wear areas. There's almost always going to be rust in these areas, unless they are zinc coated or are made of carbon fiber. You should base the wear of the rotor on two things. First, the thickness of the rotor (between where the brake pads sit on them). There is a minimum thickness these need to be. This value is sometimes cast into the rotor, or you'd need to find it in a service manual. The second thing to look for is if there is a lot of gouging in the metal from the brake pads, which happens when the brake pad gets worn out.

Usually, you don't have to consider changing rotors until you need to change the brakes. Then, for the best results, you'll either need to machine the surface of the rotor or buy new ones. The idea is to have a completely fresh mating surface for the pads to ride upon, which will give you the best braking performance the rotors/pads can provide. Until then, don't worry about them.

Answer 2

There's nothing wrong with your rotors as far as can be seen from your pictures, it's totally normal to have the edges rusty, it doesn't impair them. What's important is that the disk surfaces are in good condition, that is the part that's going to be in contact with the pad, and yours seems fine. There looks to be a good amount of metal left as well.

Answer 3

Those rotors, from the images supplied, look in good condition. They do not need to be replaced, as you don't show the other sides then I cannot be certain.

However, the top image shows a rotor that has been cleaned and prepared so that one looks really good - I assume it is one of the front ones as it is thicker with the central cooling vents. The lower images look to be of the rear rotors and they seem ok as well.