Hydraulic Happiness is when your hydraulic systems are running smoothly, without a hint of trouble. Every additional day that your hydraulic system runs trouble free, increases your return on investment (ROI). Over the next 12 articles, I plan to write about things you can do to keep them running smoothly. We’re all very busy before the holidays, so I’ll keep them short.

 

The greatest factor in determining the longevity of hydraulic components is the hydraulic fluid. Therefore, it’s important to start with the best possible fluid, but how do you really know what’s the best fluid?

The best fluid is one that has proven itself in hard working applications. From my experience, I would only use fluids that have proven themselves in service, or by proper testing. Luckily, Bosch Rexroth provides such a rigorous testing service for hydraulic fluids. The details of the tests can be seen on pages 5 and 6 of Rexroth data sheet RE90235.

After the completion of these tests, qualified technicians dismantle and inspect the pumps and motors. If these components are still in good condition, then the fluid is given a passing grade and added to the “Fluid Rating List” under data sheet RDE90245. You can find the latest version of this data sheet (dated Nov. 2021) via this link.

Fluid Rating is Valid for Five Years

Yes, this fluid rating expires in five years, as you can see in data sheet RDE90245. The way I understand it, this is because the raw materials change, production methods change, etc. Just because a particular fluid passed the test this year, there’s no guarantee that it will do so in the future. Therefore, if a fluid manufacturer wants their fluid on this list, they must apply for a re-test. As you can imagine, these tests are not cheap. That expense must be covered by the fluid manufacturer.

Fluid Selection Made Easy

So there you have it. A difficult task has been made really simple for you. If you want to have the best possible longevity for your hydraulic systems, choose a fluid that has proven itself via this “Fluid Rating List” from Bosch Rexroth; data sheet RDE90245.

For a short video by Bosch Rexroth that explains the reasons for creating this fluid rating list, click here.

Feedback?

How have you been selecting your fluid? Based on your own experience, or experience of others? Do you have another good source of information for selecting good hydraulic fluid? Please let me know via the comment section below.