Automotive Brake System

The Basics

What stops it?

• Friction– Kinetic friction– Creates heat

• Heat is brakes worst enemy

• Weight transfers to front– 70% braking performed by front brakes

Applying the friction

• Disc brakes will use pads to ‘squeeze’ the rotor

• Drum brakes use shoes to press outwards against drum

Lining material• Non-metallic

– Made from synthetic fibers (used to be asbestos)

• Semi-metallic– Made from iron and synthetic fibers– More fade resistant - harder pad– More prone to squealing

• Full-metallic– Made from sintered metals– Very hard pad

Hydraulics - it’s how the pressure is multiplied and transferred

Hydraulic pressure is distributed equally in all directions

Same line pressure to all wheelsSame line pressure to all wheels

The pressure that is applied at piston A is the same as what is applied to piston B

The hydraulic pressure is the same, but the The hydraulic pressure is the same, but the applied force can be changed by changing applied force can be changed by changing

thethe piston size. piston size.

The area of the piston is

determined by using the

formula:

3.14 X R2

The amount force is calculated

by multiplying the pressure

times the area

P X A = Force

You can’t have something for nothing

The caliper piston needs more applied The caliper piston needs more applied force for multiple reasonsforce for multiple reasons