Why Air is One of the ‘Big 4’ Contaminants of Hydraulic Oil

cavitation erosion on valve plateAir is both a normal ingredient, and a contaminant, of hydraulic oil. It’s a normal ingredient because hydraulic fluid typically contains between 6 and 12 percent by volume of dissolved air. There’s no avoiding this. And provided this dissolved air stays dissolved, it poses no problem to the hydraulic system or the fluid itself.

But if this dissolved air comes … Read more

When It’s OK Not To Load Test a Hydraulic Pump Rebuild

Rexroth A2VSL1000 hydraulic pumpDuring a recent conversation with a client, the issue of testing hydraulic pump rebuilds came up. As I explain in Insider Secrets to Hydraulics, it is essential that all hydraulic components are properly tested after rebuild. Ensuring a repaired component will perform the way it should when it’s installed on the machine BEFORE it leaves the repair shop, instills … Read more

The Official Word On Hydraulic Pump Suction Strainers

suctionstrainerclogged-resizeWhile doing some fact checking for a consulting job, I had cause to review Australian Standard AS 2671; Hydraulic Fluid Power-General Requirements for Systems. This Australian Standard is basically the International Standard, ISO 4413 with some amendments based on the local advisory committee’s input.

One of these amendments has to do with pump suction strainers. Section 8.3.3 of ISO 4413:2010, … Read more