How a Forklift Hydraulic System Works

Posted by: admin on May 15, 2018

how a forklift hydraulic system works

Most people have heard of the term hydraulics for cars and other types of machinery, but few know what the hydraulic system is exactly and how it works.

Since its invention, the forklift hydraulic system has helped people get difficult, heavy work done and create a force that we can’t produce on our own. If you are a heavy equipment operator, then it’s important to understand how these forces work and the different parts that go into them.

Different machines use the hydraulic system in different ways. In this post, we address the basis of this system, and more specifically, the forklift hydraulic system.

The History of Hydraulics

French scientist Blaise Pascal discovered the principle behind the hydraulic system over 300 years ago. Pascal learned that liquid cannot be compressed. When pressure is put on a confined liquid, the liquid transmits pressure in all directions. For example, if a container holding liquid has an opening, the liquid will try to escape at a pressure that’s equal to the pressure put into the container.

In the late 1700s, British mechanic and engineer, Joseph Bramah, used Pascal’s principles to experiment on practical applications. In 1795, Bramah patented the first hydraulic press which became the basis for the modern-day hydraulic system.

How Do Hydraulics Work?

Hydraulics work by using pressurized fluid to power the engine of a car or machine. Hydraulic presses put pressure on a small amount of liquid to create a large amount of power.

The basics of the hydraulic system go like this: Confined liquid has pressure on it from one side. That pressure forces the liquid against a piston on the other side of the container. That transfers energy into the piston, forcing it upward. The piston cannot move in the opposite direction unless the pressure is released. In terms of the forklift hydraulic system, the pistons raise the forks and keep them lifted until the hydraulic pressure is released by the operator.

The Forklift Hydraulic System

In most forklifts, the tank is integrated into the frame of the vehicle. That’s what holds the hydraulic fluid.

Besides the tank, the components of the forklift hydraulic system include:

  • The pump – produces a constant flow of hydraulic fluid to supply the control valve. Most forklifts use a gear-type pump. The pump consists of a pair of rotating gears that push the fluid in the opposite direction of the rotation.
  • The control valve – starts and stops the direction of fluid and controls where the fluid moves using spools.
  • The relief valve – protects the hydraulic system from too much pressure.
  • The return line – returns the fluid to the tank.

The types of fluids used in hydraulic systems include water-based fluids, petroleum-based fluids, and synthetic fluids. Water-based fluids are fire-resistant but do not provide as much lubrication as the other types. Petroleum-based fluids are customized to the hydraulic system with additives and are the most popular. Synthetic fluids are useful for high temperature and high-pressure systems.

How Do Hydraulics Work in a Forklift?

Using cylinders, the forklift hydraulic system works very similarly to the confined liquid example. The cylinders are sealed tubes with an inserted rod. As the hydraulic lines put pressurized fluid into the tube, the rod is pushed out as the fluid looks for the path of least resistance. Resistance is introduced to run the fluid through the hoses and connections on the different components that are powered via hydraulic pressure.

Tubing pumps the hydraulic fluid into a reservoir. The pump creates the pressure that moves the fluid through the forklift hydraulic system.

Why Are Hydraulics Important for Forklift Operation?

Forklift hydraulics raise the load-bearing prongs off the ground. The hydraulics lift and hold the load in the air while the forklift moves. A forklift hydraulic system is the heart of the machine because it is responsible for moving pallets.

Forklift Hydraulic Safety and Training

The levers control the hydraulic system in a forklift. The operator needs to be very careful with them. It’s important that only trained and certified operators use forklifts. They need to properly calculate the load and how much lift power is needed to move it. The hydraulics of a forklift have a lot of power, and only a small amount of effort can create enough force to move a large, heavy load.

The proper usage and maintenance of a forklift will keep the hydraulic system in good working condition, without needing constant repair work.

Operator training will keep all workers safe in the vicinity of the forklift, and ensure that operators have the proper understanding of how the hydraulic system works and how it is used most effectively.

Check out the online forklift training from for the most convenient and comprehensive forklift training available. Operators learn how to operate a forklift, perform equipment inspections and operate the forklift hydraulic system correctly. Sign up today for same-day certifications!


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