Archive for the "Hydraulics" Category

Troubleshooting Hydraulic Cylinder Drift

A popular misconception about hydraulic cylinders is that if the piston seal is leaking, the cylinder can creep down. Fact is, if the piston seal is completely removed from a double-acting cylinder, the cylinder is completely filled with oil and the ports are plugged, the cylinder will hold its load indefinitely – unless the rod-seal [...]

A Strange Hydraulics Problem – But True!

A few months ago, I was involved – in a supervisory capacity – in the planned change out of components on a hydraulic machine. The design of the machine’s hydraulic power unit was the all-too-common, cheap and nasty, everything mounted on the tank lid variety. You know the ones – electric motors mounted vertically, with [...]

Hydraulic equipment reliability – begin with the end in mind – Part II

In a previous article, I wrote about the advantages of defining your maintenance and reliability objectives for a piece of hydraulic equipment before you even order it. In response to this article, I received the following from one of our members: “As an engineer for a heavy equipment manufacturer, I have to take exception with [...]

Hydraulic Equipment Reliability – Begin With The End In Mind

  During a recent Hydraulic Breakdown Prevention Blueprint seminar, one of the attendees, a maintenance manager for a large open-cut mining operation, mentioned that he was considering upgrading the filtration on their fleet of hydraulic mining shovels – to achieve a higher level of fluid cleanliness. There’s lots of documented evidence to suggest that increasing [...]

A Serious Consequence Of Over-Pressurizing Your Hydraulic System

  When a hydraulic system sees a spike in pressure it won’t necessarily blow up with a bang. But damage can occur in a number of ways. In fact, a single pressure spike of sufficient magnitude can render a piston pump or motor unserviceable. Here’s how: In axial and bent axis piston pump and motor [...]

Is This Problem Destroying Your Hydrostatic Transmission?

Rupert Murdoch, the boss of global media giant News Corporation was a neighbor of ours where I grew-up. Not that my family was particularly well off. It’s just that my father’s farm happened to be situated close to a group of “sheep stations” the media mogul owned. But compared to the 300,000 acres Mr Murdoch [...]

Anatomy Of A Hydraulic Maintenance Failure

Would you part with $50 to save $70,000? This is a ‘no-brainer’ for most of us. Well, here’s a story for you: I recently conducted failure analysis and a reliability audit on a 300 kilowatt hydrostatic transmission. The hydraulic system was running a synthetic ester, biodegradable hydraulic fluid. This $45/gallon hydraulic fluid had been destroyed [...]

How Well Do You Know Your Hydraulic Equipment?

  A recent client had a set of pumps worth fifty grand fail after achieving only half of their expected service life. And they wanted some answers. At the initial meeting the client opened proceedings with a brief history on the machine, an account of the events leading up to the failures and then pushed [...]

Storing Hydraulic Cylinders – Part 2

  In a previous blog post, I discussed the procedure I use when preparing hydraulic cylinders for storage. In response to this article, one of our members sent in this question: “One issue I feel you left out of the cylinder storage issue is the orientation question. How should a cylinder be orientated for short [...]

Storing Hydraulic Cylinders – Safely

A question I’ve been asked several times in recent months by equipment owners, is the procedure for storing spare hydraulic cylinders for an extended period. So here’s what I recommend:   Always store fully retracted. Store indoors in a clean, dry area. Smear the internal surfaces of eye/clevis bushes or bearings with grease – particularly [...]