Often the maintenance needed on an engine requires a lot of knowledge and very little physical effort. This is the kind of repair work that separates the good mechanics from the bad ones very quickly. Without the proper knowledge, mechanics may work for hours before they correct a simple problem. Sometimes they may never get an engine running correctly. A good mechanic that understands engines can repair one in a few minutes. This set of lessons is written with the intention of starting you on the correct road to becoming a good mechanic. In it we describe the different engine parts and how they operate together to make an engine run the way it should.</

This part is designed to teach the knowledge necessary for performing tasks related to maintenance and repair of wheeled vehicle electrical systems. Information is provided on the fundamentals of automotive electrical systems, to include circuits, batteries, and the fundamentals and use of electrical test equipment.

This part of the course is designed to teach the knowledge necessary for performing tasks related to repair of automotive electrical systems. Information is provided on AC and DC generator systems, starting system components, battery ignition systems, and vehicle electrical accessory systems.

It is the job of the fuel system to send the correct fuel-air mixture to the engine at all times. The contents of the mixture and the amount of the mixture must be variable to meet the ever-changing needs of the engine. Through the years, it has taken a lot of research and experiments to develop the present-day fuel system. This system must be serviced and maintained properly or it will not work as it should.

The combustion (burning) of the fuel with the air in an engine includes several chemical changes. For example, for each gallon of gasoline that is burned, about one gallon of water is produced in the form of steam. Another thing that is formed is carbon monoxide, a colorless, odorless, deadly, poisonous gas.

The exhaust stroke rids the engine of most of these combustion products, and the exhaust system takes the exhaust fumes away from the engine, cuts down the noise, and gets rid of the gases so that none of the carbon monoxide reaches the people in the vehicle. For safety of personnel, proper maintenance of the exhaust system is a must.

The purpose of this part of the course is to give you the knowledge to develop the skills to service and maintain fuel and exhaust systems.

This part of the course is designed to teach the knowledge necessary to develop the skills for servicing and maintaining clutches, transmissions, and transfers. Information is provided on the construction, use, and types of clutches, manual transmissions, automatic transmissions, and transfers. Information is also provided on gears and gear trains as they apply to transmissions and transfers.

This part is designed to teach the knowledge necessary to develop the skills for servicing and maintaining drive lines, axles, and suspension systems. Information is provided on propeller shafts, axles, and suspension system components, to include springs, shock absorbers, frames, tires, and wheels. Information is also provided on inspection procedures for these systems.

A vehicle is not much use if it cannot be steered or guided. The act of guiding the vehicle is called steering. Wheeled vehicles are steered by aiming or pointing the wheels in the direction we want the vehicle to go. The driver of a car or truck guides it by turning the steering wheel. The steering system of cars and trucks consists of levers, links, rods, and a gearbox and sometimes a hydraulic system that assists the driver's steering effort.

The steering system is of critical importance in the safe operation of the vehicle. There must be no looseness between the steering wheel and the front wheels if the driver is to keep control over the direction the wheels point. The tires must meet the road at the correct angle to get good traction and to prevent unnecessary tire wear. Also, the driver should be able to hold the wheels in the straight-ahead position and change them to the right or left with very little effort.

For you, the student, a study of steering introduces many new words, parts, ideas, and theories. The study includes some math, physics, and hydraulics. This part provides you with a thorough understanding of the design, construction, operation, and unit maintenance of steering systems. Math, physics, and hydraulics are covered right in the text where they apply.

Up to this point, each one of our lessons has covered all the things that were needed to make a vehicle go forward and backward. We now know that an operator has controls to make this equipment go fast or slow; to the right or left; through mud, snow, sand; and on level roads. But what does the operator do if a child runs out in front of this moving vehicle, or when traveling on a road a point is reached where a bridge is washed out? The answer is that the operator must have one or more controls that will bring the vehicle to a stop rapidly and with a small amount of effort. The braking system provides these controls.

Braking is the use of friction to slow a vehicle, bring it to a halt, or hold it in a standing position. A brake is a device that is secured to the vehicle axle housings, which do not rotate, and is used to slow down or hold the wheels, which do rotate. When the rotating parts are brought in contact with the non-rotating parts, the friction caused by the rubbing creates the braking action.

All vehicles must be built so they meet the minimum braking requirements. For many years it has been a set standard that a braking system must be able to stop a vehicle traveling 20 miles per hour (MPH) within 30 feet. You must remember, however, this does not mean the vehicle will always stop in 30 feet. It does mean that if the tires could get enough traction on the road, the brakes must hold well enough to stop it in that distance. To get an idea of how much power is involved in braking systems, imagine a 10,000-pound truck traveling 50 MPH being braked at the rate discussed above. The energy required to do the braking would be equivalent to 500 horsepower (HP). This is much more than the vehicle engine could ever produce. Most of the braking systems on modern passenger cars can handle about eight times the power developed by the engine.

This part of the course is designed to provide you with a knowledge of how braking system components operate.