Some myths about brake systems make sense and seem to explain a problem, but they do not resolve the real issues. A lot of these myths are built from outdated history and should just go away. Here are seven myths about brake pads and brake rotors that can hinder efforts to solve brake problems.

MYTH: Heat is what determines the Minimum Thickness Specification of a Brake Rotor

Heat has nothing to do with this specification. The minimum thickness is based on how far the brake caliper piston will travel if the brake pads were worn all the way to the backing plates. If your brake pads or brake rotor were worn to below specification, the caliper piston could extend past the bore and start leaking.

MYTH: There are "Soft" and "Hard" Brake Pads

The average driver thinks of a "hard" brake pad as semi-metallic and a "soft" pad as typically an organic or ceramic. Both of types of friction materials can be the same in terms of compressibility. Calling one material soft and one hard is not accurate. Compressibility can influence pedal feel, but usually only when the brake pad is defective. What really influences pedal feel is the pad's coefficient of friction. Engineers measure compressibility as a quality control measurement and not as a performance measurement and it has very little to do with noise or rotor wear.

MYTH: Brake Line Damage Can Cause Brake Drag

All modern brake lines are usually composed of two or three layers with a stiff internal liner that is in contact with the fluid. The outer layers are typically a softer material designed to absorb impacts with road debris. If the brakes are stuck on just one wheel, a mechanic could assume that it is a restriction from inside the brake hose where the inner liner was damaged and created a flap that prevents the pressure from releasing the caliper. This could possibly be the cause, but usually if the brake line was damaged the entire liner would fail and the brake fluid pressure would make the hose bulge or burst. The restriction is more likely to be from stuck emergency brakes, caliper slides, brake booster, or valve problems.

MYTH: Wet Brakes Increase Stopping Distances

If you have drum brakes it might be a good idea to tap the brake pedal after you drove through a deep puddle to clear the water from the brakes, but with disc brakes this has become unnecessary. If the wheels are turning, water will be thrown away from the brake rotor by centrifugal force.

MYTH: Brake Pads are Regulated by the Government

There are no government regulations concerning the performance of aftermarket brake pads.

MYTH: Brake Pads Need to Warm Up

Most brake pads are designed to produce an even amount of brake torque across a wide spectrum of temperatures, including at very low heat. This is true for the exotics with carbon ceramic brakes as well as for standard everyday vehicles. The exception to this would be racing quality pads that require heat to generate its highest coefficient of friction. Manufacturers of these pads will specify these pads are only for off-highway racing purposes, and would not be something most mechanics would recommend.

MYTH: Brake Pads Are The Source of All Brake Noise

All brake pads produce vibrations when they are applied. But only if the vibrations are transferred to the vehicle, will a driver actually hear it. Typically, most high frequency noises come from the brake caliper, brake rotor or bracket. Low frequency sounds are usually caused more by the body structure of the vehicle. What usually causes brake pad noise is a change in the material due to heat. A more consistent friction material causes less vibrational excitation variation at the friction coupling by having consistent brake torque at environmental extremes of humidity and temperature. A few options to solve brake pad noise are to isolate the brake pads with lubricant, shims, and renewing the brake hardware.

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