Rusty brake rotor image by John Goreham
John Goreham's picture

Rusty Brake Rotors - When To Have Your Brakes Serviced and When Not To

If you have rusty brake rotors and are concerned that something is wrong, this story will help explain when you need to take action and when to stop worrying.
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Rusted brake rotors can look dangerous. We all know that brakes are the only thing keeping us from an accident, and when things don’t look right we are wise to investigate further. The good news is that most rust on brake rotors is not a problem.

Rusty Brake Rotors - When Not To Worry
If you use your vehicle daily and the brakes are stopping the car as they should, you may not have any problem. Brake rotors on most passenger cars are made from iron-based metals (think iron and steel) that will oxidize. We call this rust. The rust can appear on the rotors in a couple of different ways.

If you look through the wheels of your car, you can see the rotors. They are the ring that the brake calipers pinch. However, the calipers don’t pinch the whole rotor. They only contact the inner 60 or 70%. If the inner or outer portion of the ring is rusty, that’s normal.

If you have recently had rain, the humidity is high, or you washed your car in the driveway and you see rust on the rotors (see top of page image), you need not worry. This is just surface oxidation and it can happen in a matter of hours. When you drive, your pads will dust it off and there will be no problems.

Rusty Brake Rotors - When To Have Them Checked
If just one of your brake rotors has surface rust, and not all three, it is worth taking the vehicle in for service. One of the calipers may not be contacting the rotor for some reason. Perhaps a caliper is stuck.

If you store a vehicle for months or longer, the rotors can develop surface rust that is more difficult for the pads to remove. It’s worth budgeting for new rotors and pads if you store a vehicle and the brakes were not new when you did so. A mechanic can tell you if they are in need of service.

Other Brake Issues

If your brakes don’t stop the car properly, have it towed to your trusted mechanic. Don’t rely on help you find on the internet to try to determine the cause or the fix. For more information on typical brake problems, check out our story that explains the most common issues.

John Goreham is a long-time New England Motor Press Association member and recovering engineer. John's interest in EVs goes back to 1990 when he designed the thermal control system for an EV battery as part of an academic team. After earning his mechanical engineering degree, John completed a marketing program at Northeastern University and worked with automotive component manufacturers, in the semiconductor industry, and in biotech. In addition to Torque News, John's work has appeared in print in dozens of American news outlets and he provides reviews to many vehicle shopping sites. You can follow John on TikTok @ToknCars, on Twitter, and view his credentials at Linkedin


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