To ensure smooth-running hydraulic systems, use the right hydraulic oil and keep it clean and dry.

To ensure smooth-running hydraulic systems, use the right hydraulic oil and keep it clean and dry.

A lubrication reliability effort that includes selecting the right fluid and implementing the correct reliability best practices will protect metal surfaces from wear. This in turn will lead to improved uptime, reduced maintenance costs, and longer lubricant and equipment life.

Hydraulic systems have become more sophisticated in recent years, as speed and pressure have increased tremendously. Because of these changes, wear rates have gone up dramatically. Thus, the proper selection of hydraulic oil has become much more important.

Hydraulic Oil Selection Considerations

Viscosity

• Select an oil that has the right viscosity and is able to maintain its viscosity throughout its working life.
• To maintain viscosity, an oil must be able to withstand oxidation, resist foam, separate from water, and withstand effects from temperature fluctuations.

Oxidation

• Oxidation rates increase with temperature, and as the percentage of contaminants in the system increases.
• The right oxidation inhibitors can help extend oil life and prevent costly changeouts.

Foam

• When present in hydraulic fluid, foam is normally a symptom of another problem.
• Foam also causes several issues, including oxidation, viscosity changes, cavitation, micro-dieseling, elevated temperatures, reduced film strength, increased oil compressibility, and varnish.
• Controlling foam is essential to hydraulic performance. Therefore, it is very important to select a fluid that will not foam in service.

Water

• Other than fire-resistant fluids, hydraulic oils should shed water quickly so the water can be removed.
• If water is not removed, emulsification will lead to equipment failure and performance loss.

Rust and corrosion

• With the right additive package, hydraulic oil will provide long-term protection from rust and corrosion.

Putting it all together

After selecting the right oil for the job, the next step is oil analysis. This allows you to begin predictive trending of oil and asset condition. After that, you should add filtration, breathers, and sight glasses. These solutions help you keep the oil clean and dry, enabling you to safely extend the life of the equipment and the oil.