How To Bleed Air From A Hydraulic System

photo credit eaton vickersOne of our members writes:

“We have a simple hydraulic system: pump and 4 double-acting cylinders. Most of the oil between the directional control valve and cylinders ‘shuttles’ back and forth in the lines without returning to tank. The manufacturer of the system, Rexroth, tells me there is never a need for ‘bleeding’ air from the system. How can this be? There are occasions when we change a component and air gets into the system. It would seem only natural to bleed the air out. Why would Rexroth say it is not necessary? More importantly, how do you bleed such continue reading »

Proactive Maintenance: When IS The Right Time?

Hydraulic Maint HandbookNow is not a good time. It’s a popular cliché and an evergreen excuse. Fact is of course, when you’re looking into the future, there’s never a good time to do anything. Because it’s always easy to identify some logical reason why right now is not a good time to act.

Sure, the future is always uncertain. But it’s a cop-out to use it as cover for permanent inaction. And it seems to me a lot of hydraulic equipment users are guilty of this with respect to proactive maintenance. Consider this from one of our members who works for a … continue reading »

The Grave Danger of Energy Contamination

500HPU1As I often remind hydraulics users here and in my work in other places, energy contamination, a.k.a. heat, is public enemy #1 of every hydraulic system. And it’s a bigger threat to system longevity and reliability these days than particle and water contamination-due to the widespread awareness and adoption of modern filtration technologies.

Adequate lubrication of hydraulic components and efficient power transmission are both dependent on appropriate oil viscosity. If system operating temperature is allowed to exceed that required to maintain viscosity at around 20 centistokes, the likelihood of boundary lubrication conditions occurring, resulting in friction and wear, increase dramatically.… continue reading »