In a disc brake system, the calipers, pads and rotors are vital parts for operation and safe slowing and stopping. In normal situations, your rotors should be silvery or gray. However, under some conditions, they can turn to blue. This is an indication that there’s something wrong with your brakes, and it’s highly recommended that you take action as soon as possible.
How the brake rotor system works:
Disc brakes are actually pretty easy to comprehend. Pressurized brake fluid is sent through the lines from the master cylinder. In the caliper, the fluid actuates a piston, which accurately closes the caliper. This pinches the brake rotor between the inner and outer brake pads.
The harder you depress the brake pedal, the harder the caliper pinches/squeezes the rotor. In a vehicle equipped with antilock brakes, the ABS system prevents them from locking up by pulsating the brakes dozens of time per second.
The squeezing action of the caliper and pads against the rotor generates friction and heat. Friction is a necessary part here–it’s what slows and stops your car. Heat is also unavoidable, but excessive temperatures can actually generate damage. This is where bluing can happen. If one of your rotors has turned blue, it’s vital to have the problem diagnosed, as it’s a sign that something’s wrong. Over time, it could even lead to cracking of the rotor and damage to the pads, as well as reducing the rate of your safety on the road.
Common reasons why this happen:
- Locked Caliper: One very common factor for rotors to turn blue is that the caliper is locked and the brake pads remain in almost constant contact with the metal. This might be slight enough that you don’t see any drag during normal operation, but it will be enough to produce significant heat and wear.
- Corroded Slide Pins: Your vehicle’s calipers slide back and forth on metal pins. These pins have to be well lubricated, clean and free of debris. If they get corroded, the caliper will not slide in and out properly and may remain too close to the rotor rather than moving back to the start position.
- Pinched/Deteriorating Brake Line: Your brakes operates on hydraulic pressure. If there’s damage to one of the brake lines (a kink, or internal damage to the liner that reduces the amount of fluid flowing in and out), it can make your caliper to stay at least slightly engaged at all times. This produces heat and blues your rotor.
- Driver Error: If you’re a “two-footed” driver or regularly ride your brakes because you do a lot of stop and go driving or live in an area with lots of hills, you could be the inadvertent cause of the issue. Constantly engaging your brakes causes the same buildup of heat as having a locked caliper, but you’ll observe bluing on two or four rotors, rather than just one.
How brake rotor repair is done:
The mechanic will have to inspect the entire system visually. A test drive may be required, as well as other diagnostic steps. The mechanic will know if there is drag on the affected wheel/wheels from a locked caliper and then advise you on the next step in the repair process.
How important is brake rotor repair?
Having brake rotors that turn to blue is more than just an anomaly. It can develop to an expensive problem, and it can also reduce your safety on the road. Extreme heat can make your rotors to warp and even crack, and your brake pads will deteriorate rapidly, leaving you with less stopping power. If the problem affects both front brakes, you may also observe brake fade. A professional mechanics can diagnose and repair the problem for you.