Brake rotors are turning blue Inspection

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Why Do Brake Rotors Turn Blue?

Brake rotors are slowed down by the brake shoes that press outward or inward based on type of vehicle. The rotors can sometimes warp or in some cases turn a dark blue, indicating a serious braking system problem.
Basic Cause of a Rotor Turning Blue
Excessive heat will turn a typical brake rotor blue. A blue rotor indicates the rotor is being worn and could lead to cracks in the rotor, which will cause uneven wear on the brake pads that are stopping the vehicle. This uneven wear could lead to damaged calipers and brake shoes.

What Causes the Heat?
The excessive heat needed to turn brake rotors blue would require one to "ride" the brakes -- to literally be operating the vehicle with one foot on the brake. In cities where the layout is very hilly, San Francisco for example, or mountainous areas, a constant applied pressure to the brakes would cause the problem.

Other Causes
Incorrectly aligned calipers or incorrectly installed brake pads could also cause the rotor to turn blue. The brake pads would constantly be applying slight pressure to the pads even when not braking.

Solution to Blue Brake Rotors
Have a professional examine your rotors and determine the solution to the problem. Some mechanics suggest replacing the brake pads with ceramic pads; others recommend replacing the rotors with drilled or slotted rotors instead of the solid piece to dissipate the heat.

When people refer to the color of Porsche brakes, they are actually referring to the color of the calipers which serve as housing for the brake pads.

Colors
Porsche calipers come in yellow, red, black and titanium; each color has a specific significance. Black calipers are the base color for all models, and titanium calipers are on the "Cayenne S" model.

Yellow
Yellow calipers signify the special, Porsche Ceramic Composite Brakes; these brakes are optional for the "Cayman," "911" and "Boxster" models. The carbon, fine-ceramic compound of the PCCB is lighter in weight -- and more resistant to high temperatures -- than traditional iron brakes.

Red
Red calipers signify an "S" version of a particular Porsche model. The "S" stands for "Sport," and distinguishes the Sport version of a particular model. These models feature more horsepower and higher performance than standard models.

The Consequences of Not Replacing Worn Brake Rotors

Driving on badly worn rotors leads to a host of brake problems. Well-maintained rotors keep your automobile safe. The key to being safe lies in paying attention to signs of worn rotors. If your brake system makes any squealing sound, vibrates, pulsates, wobbles or shakes, the entire system needs to be checked. Checking the system means inspecting the rotors and pads for wear and the fluid level of the system. Worn rotors can lead to dire consequences.

Brake Fade
Worn rotors have less mass and therefore heat up rapidly, because the rotors no longer can absorb and dissipate the heat evenly. The rapid heat absorption leads to brake fade and accelerated pad wear. In brake fade, the rotors and pads get so hot that it boils the brake fluid in the calipers, which results in spongy brakes and less brake force. In the case of accelerated pad wear, the heated rotor develops rough spots, and these in turn eat away at the pad faster. If the rotor overheats, in most cases there isn't enough rotor to resurface, and the rotor needs to be replaced.

Brake Pulsation
According to Carroll Smith, a leading brake expert, brake rotor warp does not exist. Brake rotors do not become so heated that the brake rotor material warps. He explains that brake rotors become uneven due to pad material being transferred to the rotor, and not the rotor itself warping. The pads become so hot that the heat melts the pad material onto the rotor, forming a new material called cementite. Cementite is a rough material and a poor heat sink. Brake rotor unevenness leads to pad wear, and if unchecked, pulsation with high-speed braking. This means the tires wobble and vibrate, leading to a jerky steering column and to anti-lock brake system failure. Replacement of the rotor is critical in this case.

Corroded Brake Rotors
Badly worn rotors also result from rust, corrosion and lack of use. Rust or corrosion causes unevenness in a rotor. If you drive in extreme winter conditions where they throw salt on the road, corrosion of the rotor occurs, especially if you leave the car parked for long periods of time. If you drive with a partially corroded rotor, the corroded parts wears at a different rate then the non-corroded areas of the rotor. This uneven wear results in excessive thickness variation and a badly worn rotor. Worn rotors make the caliper piston travel farther when the brakes are applied. If the distance between the caliper piston and the rotor exceeds specifications, brake fluid leaks or the piston sticks, causing brake failure. Resurfacing of the brake rotor is warranted in this case.

How to Stop a Ceramic Brake Squeal

The squealing of ceramic brakes is common among many vehicles. The reason ceramic brakes squeal is that the back of the brake pad vibrates against the caliper assembly. This vibration causes the squealing. The squealing is normally the result of not using a brake lining shim, or not putting enough anti-squeal lubricant on the back of the brake pad where the pad touches the caliper. The lubricant needed to stop the squealing is normally available from most auto parts stores.

Step 1
Loosen the lug nuts on the wheels you are working on by turning them 1/4-turn counterclockwise.

Step 2
Jack up your vehicle using the jack points on the front or rear of your vehicle (depending on which brakes you are working on). Place jack stands under the pinch welds located along the side rail of your vehicle and lower the vehicle onto the stands.

Step 3
Finish removing the lug nuts and pull the wheel off the wheel hub assembly.

Step 4
Loosen the bottom-most bolt on the backside of the brake caliper. This is the caliper's pin bolt.

Step 5
Slide the caliper up and away from the brake rotor.

Step 6
Apply some anti-squeal to the backside of the brake pads. Only apply the lubricant to the back of the brake pad on the steel backing where the backing makes contact with the caliper housing.

Step 7
Slide the caliper back down and tighten the pin bolt.

Re-mount the wheel, tighten the lug nuts and lower the vehicle to the ground.

What Are the Causes of One Brake Wearing Before the Other Three?

The brake system on a vehicle consists of a complex system of hydraulics, mechanics and friction. On occasion, a problem can occur and cause uneven brake wear when one set of brake pads wears out faster than the rest. This problem may occur for several possible reasons.

Caliper Failure
Uneven brake pad wear most commonly occurs as a result of caliper failure. The calipers contain a piston that presses on the brake pads to stop the vehicle. When the driver releases the brake pedal, a seal inside the caliper pulls the piston away from the pad. Made from rubber, this seal can eventually lose its ability to pull back. This condition in turn causes the pads to put constant pressure against one of the brake rotors and cause that brake pad to wear significantly faster than the others.

Brake Hose
Brake hose failure takes place when the metal brake line sustains damage from impact or the rubber brake hose collapses due to age. This problem can create pressure in the hydraulic system that can force the piston caliper outward, dragging the brake pad along the rotor and causing that pad to wear at a faster rate.

Brake Pads
Manufacturers produce brake pads in mass quantities, testing them regularly for proper function before releasing them. Even with the checking, some defective pads can make it to store shelves; defective pads can wear quickly.

Slide Pins
The slide pins are the metal pins that allow the brake caliper to slide back and forth with the wheels. When these pins become corroded, the caliper can no longer slide. As a result, the caliper becomes stuck in one position; if it sticks in the right position, it can cause the pads to wear more quickly on that side. Typically, a wire brush and some grease will take care of the corrosion.

What Happens When a Brake Rotor Breaks?

Modern disc brakes are very effective and reliable. From time to time, a brake rotor can break, creating an immediate threat to motoring safety. A broken rotor must be replaced as soon as possible to protect the driver and all around him.

Types
Most rotor breaks take the form of cracks, usually around the base of the disk where it joins the hub section. Radial cracking outward can also occur. Other occasional rotor problems include warping, heat-checking, and rotor bluing, which happens when a rotor has been subjected to high heat.

Causes
Rotor cracks are usually the result of poor manufacturing. Low-quality rotors are often poorly cast from non-homogeneous cast iron, and these defects leave weak spots that cannot withstand the forces generated during braking. A rotor that is still in service long after it has worn out will also be susceptible to cracking.

Effects
Even the slightest defect on the rotor will cause low-frequency vibrations, known as judder, during braking. Serious rotor failures can easily cause a complete wheel lock-up and loss of control of the vehicle.