How does the hydraulic braking system in your car work? This is an intriguing question, as it seems very little effort on your part can result in a rather large and heavy object (your car) coming to a stop quite quickly. In scientific terms, this is known as a force multiplier. So how does it all work?

You Can't Squeeze Liquids

To understand hydraulics, first you need to understand that liquids are basically incompressible. This is another scientific term, but it basically means that because the particles in the liquid are so close together they cannot be compressed even further. As a consequence, the pressure contained within the liquid is transmitted equally in all directions. You can see this in action if you drill several holes in your bucket and fill it with water. The water will emanate from the bucket at equal pressure, at the same velocity and travel the same distance.

Transmitting Force

Because liquids have this "incompressible" element, they can be used to transmit pressure between two points. When a hydraulic system is set up, a small force created at a small cross-sectional location, such as the brake pedal, will transmit pressure by moving the liquid through a pipe to another location. An increased force is applied at the other location, (in this case the pistons of the brake caliper), causing an exponentially larger effect at that end.

In more simple language, when you press the brake pedal with reasonable force, an even greater force is applied to the brake caliper, slowing each wheel down efficiently enough to stop. The brake fluid within the pipes does not compress when you put your foot on the brake pedal, but rather it is pushed forward under force and creates even greater pressure at the brake caliper.

Let the Force Be With You

A couple more technical terms. When you put your foot on the brake pedal, this is known as an effort force, which means a force used to move objects over a distance. When the brake fluid arrives at the caliper, it will exert a load force, which is another name for a force that resists or opposes the effort force.

And the force multiplier? As the pistons in the brake caliper are larger than the piston at the brake pedal, a larger load force is exerted on the brake discs than the one applied to the pedal. This is the force multiplier and is therefore an element that increases the effect of a force.

For more information, contact a brake repairs specialist.