Sample Questions to Chapter One of the AudioLearn Study Guide

THE FUNDAMENTALS OF BRAKING

To understand braking systems, it is important to know the different types of braking systems, how many braking options are in a vehicle, and what affects the function of a vehicle’s brakes. In every automobile and light truck vehicle, there are two types of braking system. These systems are the service brake and the parking brake system. You can view these systems in figure 2 of the AudioLearn Study Guide PDF.

Figure 2

The service brake is generally used in slowing down or completely stopping a vehicle and it is operated by stepping on a foot pedal generally located at the left side of the accelerating or gas pedal. The modern service brake consists of components such as the drum or disc brakes, brake pads, push rods, master cylinders, and valves. In some vehicles, disc brakes are used on all four wheels while for others disc brakes are used on the front wheel and drum brakes on the rear wheel.

The parking brake is generally used for holding and keeping a vehicle in place when it is stationary or parked. This is why it is called the parking brake and it is generally located between the driver and passenger seats or on the steering wheel. The parking brake is

Figure 3

EXHAUST BRAKES

An exhaust braking system functions by restricting the flow of exhaust gases passing through the engine. Exhaust brakes achieve this by closing the valve located in the exhaust manifold which results in high pressure building up in the exhaust manifold and the engine’s cylinder. The restriction of the exhaust flow causes the engine speed to slow down thereby decelerating the vehicle. The exhaust braking system is used in heavy-duty vehicles such as tractors and trailers.

Figure 4.

PARKING BRAKES

In earlier sections, it has been stated that vehicles are generally equipped with both a service brake and a parking brake. To accurately diagnose the parking brake system, an understanding of how it functions is needed. Parking brakes are mechanically operated systems which are used when parking an automobile or light truck. When applied, the parking brake generally applies the braking units or assembly to two wheels of the vehicle.

There are different types of parking brake systems and they include transmission mounted parking brakes and drum-style parking brakes. Drum-style parking brakes are used on vehicles with disc brakes and mechanical linkages are used to operate this type of parking brakes. On the other hand, transmission mounted parking brakes use a small drum brake to prevent the vehicle’s drive shaft from turning. The parking brake system also consists of components such as parking brake cables, and the mechanisms designed for its application.