In an effort to get away from asbestos in

In an effort to get away from asbestos in cars’ brake material, manufacturers have introduced semi-metallic pads and shoes. Although the semi-metallic material has been around for a number of years now, its use continues to prompt questions from both car drivers and the technicians who service those cars. , Following are common questions asked about brakes on today’s automobiles.

• My technician has used the term "brake fade" when talking about my car’s braking system. What is brake fade ?

Brake fade is the reduction in sliding force between the surface of the brake pad (or shoe) and the rotor (or drum). Fade occurs as the pad temperature rises and the resins in the pad begin to “boil.” The vapor then acts as a lubricant, preventing direct contact between the pad and the rotor.

The point at which the fade becomes noticeable to the driver, he added, depends ■on the composition of the pad, the,area where the pad contacts the rotor, and the ability of the brake system to lose heat.

• Do semi-metallic pads reduce brake fade?

Yes, for the most part, because today’s braking systems generate higher temperatures, mpre manufacturers are installing semi-metallic pads because they conduct heat more effectively than asbestos pads.

Asbestos lends to retain heat at the friction surface, leading to face conditions; semi-metallic tends to transfer heat from the friction surface, thus reducing fade.

• Why are brake temperatures higher on newer vehicles?

Mostly because today’s cars are lighter in weight,and contrary to what you might think, lighter weight increases, rather than decreases, the temperatures generated by the brakes.

Front-wheel drive has reduced overall vehicle weight, but it has also put more weight in the front end of the car. An older, rear-wheel car might have 55 percent of its

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