We do not live in prehistoric times and we do not stop our cars by putting our feet on the pavement. The average automobile weighs approximately 3500 lbs. It takes a lot of force to stop that much weight when it’s

moving down the road. So, how does it go from a light push on the oblong pedal on the left to transmitting enough force to stop your car?

  When you depress your brake pedal, your car transmits the force to its brakes through a fluid pressure system. Since the actual brakes require a much greater force than you could apply with your feet, your car must multiply the force. It does this in two ways: leverage and hydraulics.

  The force you assert on the brake pedal is leveraged against a plunger in the master cylinder, which forces fluid through the brake lines and hoses. A reservoir on the brake master cylinder holds the hydraulic fluid for

the system. The basic idea behind any hydraulic system is very simple: force applied at one point is transmitted to another point using an incompressible fluid, almost always an oil of some sort. Most brake systems also

multiply the force in the process using a hydraulic or vacuum brake booster. The hydraulic force is multiplied as it travels through the smaller lines and hoses of the brake system; much like water moving through a garden

hose nozzle. There’s enough force at the end of the cycle to close the pistons of the brake calipers, causing your brake pads to close on the rotors and bring your car to a halt.

  Many things can go wrong in this process making it near impossible to stop your car. The most common problem is a loss of hydraulic pressure. If there’s a rupture in your brake system, fluid will leak when you press

your brake pedal. Your brake pedal becomes soft or mushy. You will eventually lose your brakes completely, I guarantee it. The other problem is a hard brake pedal. This is a clear indication your brake booster has failed.

You’re literally pushing all the hydraulic fluid with your foot when the booster fails. Either of these problems must be taken care of immediately.

Lose your brakes and you become a 3500 lb missile flying down the road. Your prehistoric foot brake will not save you, no matter what your strength. You’re destined to have a collision.