The braking system is of course responsible for slowing down a vehicle when necessary by converting kinetic energy into heat. This is achieved through the use of disc brakes or drum brakes (only found at the rear wheels of some vehicles). The braking system also incorporates the hand brake (aka e-brake). All modern vehicles use a hydraulic system to activate the brakes and utilize the help of a servo mechanism to make application of the brake pedal easier. Faults that can occur to the brake system are numerous. Parts such as brake pads, brake shoes, discs and drums often need replacement due to friction. Parts of the hydraulic system such as the master cylinder, pipes, calibers etc are subjects to leaks and failure. Overheating the brakes can also result into failure or even distortion of machined surfaces. The servo mechanism is of course also subject to failure. And finally parts such as the hand brake or drum brakes may require adjustment as part of the vehicles routine maintenance. Correct maintenance of the braking system is crucial for the safety of the passengers.