5 Things to Know About Hydraulic Fluid

The hydraulic system

Hydraulic fluid is one of the key components in making a machine. Any kind of modern industrial use, commercial vehicle, or even household appliance uses hydraulic fluid in some way. This fluid, along with the physics that has been developed around it, has been instrumental in changing the way people live their lives. Operating cars, trucks, trains, boats, planes, and machines would not be possible without this fluid. Hydraulics is the main way people control anything heavy, and it is how builders have used large cement blocks and pipes to make buildings. Keep reading for some of the main things you need to know about hydraulic fluid.

1. Fluid Transmits Hydraulic Pressure

Hydraulic fluid is the key component of a hydraulic system. The hydraulic system‘s purpose is to conduct pressure from one end of the system to the other. If you press on the brakes of a car, you’re applying pressure to one end of the car’s hydraulic system. The force you apply will cause the hydraulic fluid inside to squeeze and transport the pressure through the system to the output, the brakes. The pressure on this end will generate a very big force, which is used to press the brakes on the tires to slow them down. Essentially, the fluid allows you to convert a small force, like the one you make by pressing your foot down on a pedal, into a big force, like the one used to slow down the tires.

2. Engineered Performance of Commercial Fluids

Hydraulic fluids can be used up to thousands of times a day on average, depending on which machine they are in. This constant use can affect the fluid, so to ensure that it lasts for a while without needing to be replaced, producers of this fluid have started to modify it to make it more stable. Increased viscosity allows for a more uniform spread of pressure, while increased temperature stability is important in high-heat environments. Many fluids are also treated to make them resistant to oxidation and foaming.

3. Numerous Fluid Varieties

Fluids are used in virtually every industrial machine out there. Since there are so many potential uses, there are countless variants of hydraulic fluid that are suited to the specific task you’re buying it for. The main fluid classifications are mineral oil-based, water-based, and synthetic, and all of these have their own set of benefits. For example, the Skydrol 500B-4 Aircraft Hydraulic Fluid, which is a synthetic fluid, is highly resistant to extreme temperatures and climates, which is what aircraft experience all the time, making it ideal for planes.

4. Fluid Maintenance Required

Due to the level of stress hydraulic fluid faces with regular use, it’s important to maintain and replace it regularly. Over time, contaminants like water and dust can leak into the container which houses the fluid. This can dilute the fluid, making it harder for it to maintain pressure. To maintain performance and to make sure the hydraulic system is not getting damaged, filter the fluid, clean the system, and replace it all every few months.

5. Essential Compatibility Check

Different kinds of fluids are made for different uses, and the hydraulic systems that complement them vary, too. It’s important to check for compatibility between systems and fluids since if you fill a system up with any kind of fluid you have laying around, it may damage its seals and hoses. More importantly, if there’s even a slight amount of leftover hydraulic fluid before you add more and two different hydraulic fluids mix, it can result in a chemical reaction that either damages the system as a whole or just the fluid to the point that it’s not useable.


Hydraulic fluid is a cornerstone of society and modern industry. Without it, commerce would collapse as no products would get made, and people wouldn’t be able to get anywhere. This fluid is used in most of the things you see every day, and it has allowed humans to control things they would never be able to control based on their strength. If you’re interested in getting the best hydraulic fluid suited for you, then you must make some considerations about what you need. However, if you use the information in this article, that decision should be a little easier.

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