Certain mechanical ("performed by a machine") parts are vital to the running and coordination of a car. They let fluids flow, or prevent fluids from escaping. They push onto or into other mechanisms to make them work, or they pull other things along. They take power and transfer it, or they magnify the power received and send it on. In reality there are just a few basic types of mechanical parts that occur many, many times in different forms, shapes, and sizes with different functions. It will make an understanding of cars a lot easier if they are familiar to you.

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- A switch turns the power (usually electrical) on and off to a component. It opens up or closes off a flow of energy from one point to another.

- A hose carries fluid or air from one place to another.

- A spring holds tension and releases tension.

- A seal prevents a liquid from escaping from a specific area where it is needed; or prevents unwanted oil, water, or other substances from entering an area where they are not wanted.

- A pump creates constant pressure to move fluid to where it is needed.

- A valve is like a door which opens and shuts to let fluids or gases pass in or out.

- A piston is a plunger that moves up and down and pushes some other part (like a shaft) in the process.

- A shaft is a long piece of connecting metal often attached to a piston at one end and usually a gear at the other. It transfers power between two points as it turns.

- A gear is a disc, roller, or shaft with teeth. One gear connects to another gear of smaller or larger size by having teeth of the same size that fit into one another (called intermeshing). Smaller gears have fewer teeth and larger gears have more teeth. A gear may be attached to and receive power from, or transfer power to, a shaft.

- A bearing is a lubricated component connecting a shaft and another mechanical part that allows the shaft to turn with greater ease.

- A pulley is a round disc with a groove in it for holding or gripping a belt .The pulley moves in a circle and it either drives or is driven by a belt.

- A belt connects two or more pulleys, being turned by one of them and in turn driving the other.