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How Caterpillar Backhoe Loaders Work

Inside a Backhoe Loader
This cutaway drawing shows many of the major components of a Caterpillar backhoe loader.
This cutaway drawing shows many of the major components of a Caterpillar backhoe loader.
Graphic courtesy Caterpillar

As you've seen, backhoe loaders are filled with hydraulic valves and cylinders. In addition, backhoe loaders have all sorts of things you would find in any tractor, car or truck. In this section, we'll look at some of the components that make a backhoe work.

All backhoe loaders have a set of standard components. In any backhoe, you'll find:

  • An engine - In a typical backhoe loader, the tractor, loader and backhoe are all powered by a diesel engine. The Caterpillar 80-horsepower 3054 engine below has a 4-cylinder, 4-stroke, direct-injection design. It also features a dry-type, radial-seal two-stage air filter and a thermal starting aid that allows the engine to start up even at -20 degrees Fahrenheit (-29 C). The basic model is naturally aspirated, but some Caterpillar backhoes have a turbocharged design. To learn more about engines, check out How Engines Work, How Diesel Engines Work and How Turbochargers Work. Photo courtesy Caterpillar The diesel engine from a Caterpillar backhoe
  • A transmission - To apply the engine power to the tractor and the backhoe and loader hydraulic systems, you need a transmission. A backhoe transmission does the same basic job as the transmission in your car -- it lets the operator switch between gears, go forward or in reverse and use engine power efficiently. Backhoe loaders come with either automatic or manual transmissions. The Caterpillar power-shuttle transmission below provides four speeds, as well as forward and backward. It has forward and reverse hydraulically shifted shuttle clutches, which let the operator change direction and travel speed on the go. It also has a torque converter that enables maximum power efficiency. To learn more about transmissions, check out How Manual Transmissions Work, How Automatic Transmissions Work and a number of other articles in the transmission category. Photo courtesy Caterpillar The transmission from a Caterpillar backhoe
  • Axles - The wheels in a backhoe loader are turned by axles. The Caterpillar standard rear axle shown below has a special enclosed design that protects it from the elements. This lets the backhoe operate reliably, even in extremely harsh environments. Photo courtesy Caterpillar A standard rear axle from a Caterpillar backhoe
  • Brakes - Just like your car, backhoe loaders need brakes in order to stop moving. Caterpillar backhoes use hydraulically-actuated, self-adjusting disc brakes to stop the tractor. They have a separate parking brake that the operator applies with a hand lever. To learn more about brake systems, check out How Brakes Work. Graphic courtesy Caterpillar A close-up of the rear brake from a Caterpillar backhoe

These components, as well as all the other backhoe parts we've looked at in this article, are all assembled on a sturdy steel frame.