How to Drain Hydraulic Fluid

Removing as much old hydraulic fluid from the engine as possible is always the goal of an oil change! Numerous strategies enhance the amount of fluid that leaves the system.

draining a hydraulic fluid

One option is to make sure all of the hydraulic cylinders are closed. When the parts are closed, there isn’t much oil left in them. The same holds for any other hydraulic expansion component.


Importance of Draining Hydraulic Fluid

Hydraulic fluid can be contaminated in a variety of ways!

In the equipment production process, there is contamination built in, and in the fluid manufacturing process, there is contamination.

Additionally, corrosion, abrasion, cavitation, and other contaminant buildup occur during usage. Catalytic contaminants, such as water or air, follow. 

Abrasive contamination can also result from seal leaks, harming your equipment’s performance. These are the reasons why it is important to know how to drain hydraulic fluid.

Hydraulic fluids become less effective as they age due to impurities in the fluid, and the fluid itself degrades naturally. Hydraulic fluid should be changed as part of your equipment’s regular maintenance schedules.


Prioritizing Safety During Draining of Hydraulic Fluid

Don’t forget the basics of safety before you begin the process. Before disconnecting the hydraulic lines, you must first alleviate the pressure. 

Under high pressure, hydraulic fluid can penetrate the skin, necessitating a trip to the doctor (and possibly even surgery!). When searching for leaks, don’t use your bare hands. Working with hydraulic fluid necessitates the use of gloves at all times. The hydraulic fluid might heat up during usage. Therefore, you should wait until the system has cooled down to replace the oil.


Maintaining the Equipment’s Security

You’re not the only one at risk when performing routine maintenance on hydraulic oil. Your machine can be harmed if you aren’t careful here. Do not open the reservoir cap unless essential to prevent contamination of the hydraulic fluid.


Useful Tips and Advice

To ensure that all hydraulic cylinders are closed and no oil is left in the components, an often-overlooked but crucial step is to check sure they are all in their closed positions.

  • Air must be allowed in to allow the oil to flow out. 
  • Desiccating breathers must be installed in the breather ports to keep moisture (and other impurities) from entering the system. 
  • You should also remove any return filters because they can contain a substantial amount of hydraulic fluid and cause it to be obstructed from flowing.

The next step is determining which ports you need to drain the hydraulic fluid. Although the primary reservoir will have the largest drain port, there may also be drain ports for other components – particularly those in low areas of the circuit.