How a Simple Car Braking System Works

A short description to help you learn about a simple brake system by Eric Roberts.

In this article I would like to give a small incite into the workings of an average family cars braking system. Larger cars such as Mercedes and BMW's have much more complicated systems, and therefore more confusing and technical to explain.

Brake pedals are made of very strong steel and work on the principle of a lever. This lever transmits the force from you pressing the pedal with your foot to a part called the "Master Cylinder". On the pedal there is also an electric switch that operates the brake lights: when the brake is pressed the brake light comes on at the rear of the car.

When pressed, the pedal transfers force to the master cylinder via a push-rod. Master cylinders are storage reservoirs for brake fluid and also contain a piston. This piston pushes the brake fluid to the rest of the braking system via brake pipes. These pipes are usually made of copper alloys, and rust in these is are a common fault found on the annual MOT test. Any leak here: no brakes!

Brake pressure is then transferred from the master cylinder to the brake calipers or wheel cylinders, normally located just inside each of the wheel hubs. Most modern cars have disc brakes on all four wheels, but older cars have drum brakes on the rear wheels, becasue it was easier to make the handbrake work on drum brakes.

Disc brakes are more efficient than drum brakes, hence the change to having all four corners on discs.

Brake pads are very important and must be checked and changed at regular intervals. Pads are made to withstand a great deal of heat and pressure to cope with the speed and stopping distances of the modern car. Brake pads are made of a metal and an organic compound to cope with such conditions. They have a steel backing which must be kept from the discs, or it will damage them. Older motorists will remember that brake pads were once made of asbestos compounds, which are now outlawed because of health and safety issues that are connected to cancers.

Brake drums and discs are usually made of high strength steel or cast iron, these too must be checked for wear at regular intervals, and can warp in time, giving bad vibrations and poor braking.

Brakes are better left to the professionals and should be checked out at every service interval. Your brake efficiency is checked at every MOT, but as yet the test does not include a visual inspection, it is wise that you have this done.

Many of our customers do not know that they have a brake problem until they hear a very loud grinding noise (caused by the metal backing on the pads scraping away the surface of the disc), by this time much damage will have been done, leaving the surface of the disc rough so that it wears away new pads in no time, but does not stop the car as well.

It is always better to have your brakes checked at regular intervals at a reputable garage or service centre and make sure that the parts that are fitted are quality parts.

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