Know All about Your Vehicle’s Brake Discs

Brake Discs

In a car one of the most crucial parts is its Disc Brake system. Brake discs do an important task to stop vehicles whenever and wherever required. The disc brake system includes the brake pads, a brake calliper and a brake disc. In the 1890s the development and usage of disc brakes began in England. Patented by Frederick William Lanchester, the first disc brakes were used on Lanchester cars. With the advancement of technology, more disc brakes were used and finally proved its power at the Le Mans auto race in 1953. They were used in contrary to the drum brakes used by the opponent cars.

Nowadays all the cars have their brake discs on the front wheels but some of them have it on the rear wheels too. They are normally manufactured from grey iron, a form of cast iron but can also be made of composites like reinforced carbon or ceramic matrix composites, attached to the wheel and/or the axle for high performing vehicles.

In order to hold back the wheel, brake pads that form friction, are mounted on a device called calliper, which is forced against both the sides of the disc. This friction becomes the reason for the wheel to stop. Here the energy of motion is converted into waste heat. When compared with drum brakes, disc brakes provide with a better performance because the latter gets cooled instantly. Also they are less prone to fading when its components start to overheat. Disc brakes recover fast from immersion too.

In contrast to drum brakes, disc brakes have no self-servo effect and its braking force is always in line with the pressure on the brake pad by the braking system via any brake servo, braking pedal, or lever. This makes for smooth driving and avoids impending lockup.

The brake discs are in a way similar to the brakes used in bicycles; the difference being that the bicycle brakes include a calliper which crushes the brake pads against the wheel, while in a brake disc system the brake pads squeeze the brake disc instead of the wheel and the force is spread accordingly.

Disc brakes have now become popular with an increase in its usage on very large and heavy road vehicles, whereas formerly large drum brakes were nearly common. The reason for such a change is the disc’s lack of self-assist which makes brake force much more predictable. For instance a heavy loaded truck with disc brakes could be stopped in about 120% the distance of a passenger car, but with drums brakes the stopping would take about 150% the distance.

Solid, vented, drilled and grooved are the various designs of the disc brakes. A solid brake disc consists of a solid disc of cast iron. Vented brake discs are hollowed out with fins or vanes between the two sides of the brake disc. This allows air to be pumped through the brake disc to provide cooling. This is usually included as part of the casting process. Drilled and grooved brake discs are manufactured to also improve the cooling.

The discs can get damaged in four ways namely, scarring, cracking, warping or excessive rusting. Scarring occurs if brake pads are not replaced on time when they reach the end of their service life and are damaged. For prevention, timely checking or inspection of the brake pads for wear should be done. Limited to drilled discs, discs may develop small cracks around edges of holes drilled near the edge of the disc due to the disc’s irregular rate of expansion in severe duty conditions. These cracks appear on the brake discs because of the repeated hard braking. As they cannot be repaired, they call for an urgent need for replacement of the Brake Discs in your vehicle.

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