Automobile brake pads

Figure 8.3. Automobile brake pads made from phosphate fibers.

Liquids are practically incompressible. In fact, the molecules are so close to one another that even the application of many atmospheres of pressure does not significantly decrease the volume. This makes liquids ideal for the transmission of force, as in the brake lines of an automobile. The force applied by the driver s foot on the brake pedal does not compress the brake fluid in the lines rather, it transmits the force directly to the brake pads, and the friction between the brake pads and rotors (that are attached to the wheel) stops the car. 

The properties of asbestos supported the development of many different materials that were incredibly strong and heat resistant. The use of asbestos in automobile brakes was the industry standard because asbestos resists heat when brakes are applied and because of its strength, which makes the brakes pads last longer. In 1972, OSH A began to regulate exposure to asbestos in general industry (U.S. Department of Labor, 1995). 

It is obvious that the cured brake blocks must be very strong if they are to withstand the abuse that friction products must endure. The horsepower of an automobile may be as high as 50 to 100, but the brakes on the same automobile must be 400 to 600 horsepower if the brakes are to stop the automobile in one-sixth the distance required to accelerate the automobile, by its engine, to speeds where brakes are applied to stop the automobile. The major fraction of the kinetic energy of the automobile is suddenly converted to heat in the brakes, and the temperature may rise abruptly from 0 °F to 1000 °F in a matter of seconds. Thermal shock alone would destroy an inferior brake pad. 

To explain this, let us consider the inspection of an automobile, which has a strong analogy to audits. We suggest the following questions Are the fan belts tight and not worn Are the brake pads worn past the limit Are the fluids at the proper level ... 

For fiber production, h. is cut when the male plants are in full flower and shedding pollen. The subsequent retting and scutching processes are similar to those for - linseed and - flax. H. seed contains 32% oil, 25% protein and 20% starch. Seed of h. is also useful as food. The oil (rich in C18 2 and C18 3) was used for centuries as burning oil for lamps, and its leaves and flowers were used in pharmaceutical applications. After solvent extraction, the meal may be applied as animal feed. H. fibers are also being used for the manufacturing of paper and technical filters and for the pads of brakes and clutches as well as insulation, e.g., in house construction or in automobiles. 

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