Q. What is brake fade?
A. Pad bite is called the coefficient of friction. At high temperatures, all brake pads have a reduced coefficient of friction. This is called brake fade. Power Stop engineers all of our friction compounds to resist brake fade. This assures safe, consistent stopping power. Our technical data page shows benchmarking information. Different grades of pads will have different fade characteristics. The Z36 pads are by far the most fade resistant pad that is commercially available.

Q. What causes brakes to squeal?
A. All rotating objects have vibration. This vibration can become amplified at specific natural harmonic frequencies. Have you ever noticed a little vibration in your car as you travel at a certain speed on the highway, and then it goes away as you go a little faster? The wheels were passing through one of these harmonics. Brake noise is caused by vibration primarily from the rotor, pad and caliper. The causes are complex and include things like the compressibility of the brake pad, the surface finish of the rotor, the stick-slip oscillation at certain temperatures, rotor dimensional run-out, rotor harmonic frequency and many other factors. Noise attenuation is a complex part of friction development.
Power Stop Evolution and Posi-Mold pads feature dual active rubber coated constrained layer shims. The rubber is placed on both the pad side and caliper side of the shim. This helps reduce vibration that can be transmitted from the pad to the vehicle. Noise can be reduced by putting a silicon based material on the back of the plate where the caliper piston makes contact. It is also important to turn the rotor and make sure the rotor flange is parallel to the hub mounting surface. One sure fire way to make noise is when a pad overhangs the edge of the rotor or encroaches on the groove between the rotor hat and smooth flange surface. It is important that you check how the pad seats on the rotor when you change the brakes .

Q. What causes rotor warping (a.k.a. pulsating brakes)?
A. The term ?warped rotors? is commonly used to describe brake pulsation, but the rotor is not actually warping at high temperature so the term ?warped rotors? is not accurate. The primary cause of brake pulsation is from uneven friction deposits on the rotor. As the brakes get hot, friction material from the pad is deposited as a very thin layer on the rotor. If you come to a hot stop and clamp your brakes down, the pad continues to deposit material on one spot. As you continue to use the brakes, this high spot on the rotor will get hotter than other parts of the rotor. When the temperature starts to exceed 1150 F, the crystal lattice structure of the iron can change into a very hard, brittle material called cementite. Your brakes can hit 1100 F or higher coming off a highway ramp with severe deceleration. Hard spots start to form, and it doesn?t wear down like the rest of the rotor. The hot spot nodules will not dissipate heat as well as the neighboring material, so it gets hotter than the rest of the rotor and causes the spot to grow. The result is a permanent high spot that you feel as pulsating brakes. You can try to turn down the rotor, but chances are the nodule is bigger than the cut depth on the lathe. So it is just a matter of time before the pulsation will come back. However, you can prevent brake pulsation two ways: 1) use a high quality, properly drilled rotor to keep the temperature low, and 2) don't clamp down on your brakes after a hot stop!

Q. What is the best way to improve brake performance?
A. In order of effectiveness: 1) Get really good tires that grip the road, 2) select the right brake pads with a high coefficient of friction, 3) use cross-drilled rotors to improve convection heat transfer.

Q. How do I break in the pads?
A. The break in procedure is critical! If you do not break in the pad properly, it can result in brake pedal pulsation and thermal shock to the rotor causing stress cracks. Break in the pads as follows: 5 aggressive stops at 50 mph to 10 mph without letting the brakes cool and try not to come to a complete stop. Then do 5 moderate stops at 30 mph to 5 mph and do not let the rotors cool after each brake application. You should expect to smell some burning resin. Finally, drive around a little and let the brakes cool down. This assures proper friction deposition to prevent brake pulsation.

Q. What brake fluid do you recommend?
A. Please avoid using DOT 5.0 synthetic fluid unless specifically recommended by the vehicle manufacturer. Some synthetic fluids can cause rubber piston seals to break down. Power Stop recommends replacing brake fluid on every pad change with a DOT 3.0 or 4.0 fluid as specified in your owner's manual.