Disc Brake

These are the most common type of brakes used in modern cars and bikes. Disc brakes use calipers to press brake pads against a disc attached to the wheel. When the brake pads come in contact with the disc, a huge amount of friction is created which ultimately ceases the movement of the wheel.

Typically, the front wheels of a car are installed with disc brakes and the rear wheels are installed with drum brakes. In some cars, all four wheels have disc brakes. Hydraulic disc brakes are the most commonly used disc brakes to help in retarding the motion of a wheel. There are two types in hydraulic disc brakes:

1. Floating Caliper Type (or) Self adjusting Disc brake
2. Fixed Caliper type disc brake

Floating Caliper Type Disc Brake:

In a floating caliper type, the caliper is not fixed in its position around a disc. The caliper slides from left to right through pins and bushings so that the brake pads come in complete contact with the disc and cease the movement of the wheel. It has only one piston to transfer the brake pressure to the brake pads.

When brake pedal is pressed, hydraulic fluid from the master cylinder is supplied to the caliper. The brake fluid applies the brake pressure on the inner side of the piston. The piston presses inner brake pad against the disc. Since, the disc is fixed, the caliper slides from left to right, therefore bringing the outer brake pads in contact with the disc. This produces a greater friction, thereby stopping the disc from rotating.

Floating type disc brakes are lighter, cheaper and more reliable. It is used in most of the vehicles.

Fixed Caliper Type Disc Brake:

In a fixed caliper type, the caliper is solidly mounted on the caliper bracket around the disc. Unlike the floating type, it has a minimum of 2 pistons, one on each side. The number of pistons can go up to 6 (3 on each side). The pistons push the brake pads against the disc, therefore retarding the motion of the disc.

The advantage of multiple pistons is that the brake pressure is distributed evenly on both sides and there is more squeezing power on the pistons.

It is more expensive than the floating type and usually preferred in luxury cars. For ABS application, both disc brake types are compatible.

Most of the vehicles are equipped with ventilated discs. The vents help in dissipating the heat, therefore cooling it down.