Working of Disc Brakes in a Vehicle

The disc brake system converts the hydraulic pressure generated at the master cylinder into a frictional force against the rotating discs which is located on the wheel.

Mostly modern vehicles have disc brakes on the front wheels and some have disc brakes on all four wheels. In this article let us discuss about the working of disc brakes in a vehicle.

Working of disc brakes in a vehicle
Before going to the working of a disc brake first let us know what are the components present in disc brake system. The disc brake system consist of a brake pedal or brake lever, a push rod,a master cylinder,piston, return springs, caliper assembly, brake pads and rotor / brake disc.

When a brake lever or pedal is pressed by the drivers foot, the push rod which is connected to brake pedal and master cylinder piston.

The push rod pushes the master cylinder piston. This movement allows the piston to slide and push the return spring which is located inside the master cylinder. The master cylinder acts as a brake booster. This movement generates the pressure in reservoir tank. This movement allows the brake fluid in the reservoir tank to flow into the brake hosepipes. A seal is equipped around the reservoir tank to make sure that the brake fluid does not go other side.

The brake fluid enters the cylinder of caliper assembly through brake hosepipes. This pressurized fluid pushes the caliper piston. The caliper piston may be one or more depending on the requirement. Then the caliper piston pushes brake pad. Now the brake pads sticks with brake disc, due to this process a friction is created between them and stops the brake disc/rotor to rotate. In this way the disk brake system stops the vehicle.

A lot of energy is absorbed while applying the brakes, so friction between braking parts generates heat. Brake parts are made of rigid material which can withstand very high temperatures. The friction surface of a disc is exposed to air for cooling. Unlike drum brakes, disc brakes throw off the water, when a vehicle is driven through water, they operate immediately. This is how the disc brakes normally works. Vented disc brakes are equipped with a set of vanes, between the two sides of the disc, used to pumps air through the disc to provide cooling.

Disc brakes need higher pressure to operate than drum brakes, for this a power brake booster is equipped to reduce the pedal forces that is applied by the driver. In some vehicles, drum brake is built into the center of the rear disc to provide parking brake operation.