September 8, 2009 

'Inside Hydraulics' Newsletter

1. Now is the time
2. A testing problem
3. Read hydraulic schematics - like an expert
4. Content for your web site or e-zine
5. Help us spread the word
6. Tell us what you think


Now is the time

Now 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.

For example, back in 2005 when I borrowed big to buy my current home, I didn't feel at all comfortable 'sticking my neck out'. At that time crude oil was around 60 dollars a barrel and some economists were predicting it could break 100 dollars within a year or two - and oil prices at this level would have a crippling effect on the economy.

This prediction turned out to be right - and wrong. As I recall, at the height of the boom, crude oil got to around 137 dollars a barrel, but it wasn't the oil price which nobbled the economy.

Obviously, we all know this now with the benefit of hindsight. But at the time, I can remember thinking that it wasn't a good time to be taking on a lot of debt. As it turned out, with the benefit of hindsight, it was actually a very good time. But like I said, it definitely didn't look that way at the time.

And the reason I went ahead and did it anyway had nothing to do with some sort of midas touch on my part. It was because we had literally grown out of our current home. In other words, doing nothing was not an option.

Yes, 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 owners are guilty of this. Consider this from one of our members who works for a large corporation and a major hydraulic equipment user:

"Brendan, having read a lot of your information I can see the benefit to the company. Unfortunately we are down-sizing including my staff and right now I can't afford the time to look into our hydraulic systems more closely, nor can I delegate the responsibility to a member of my staff."

If you're someone who understands the economic benefits of getting your hydraulic equipment running lean and mean, this is ironic. But not really surprising in the context of this discussion. Because the short translation is: "I can see the benefits, but now is not a good time."

Trouble is, when things are booming and production is king, the story is slightly different, but the short translation is exactly the same: "I can see the benefits, but now is not a good time."

In a way, you can't argue. Because there is never a good time. When things are busy you're too busy, and when things are slow you don't have the resources. This results in permanent inaction.

Which is why NOW is the time to sort out your hydraulic equipment. Because there's never a 'good' time. And doing nothing is not a sensible option.

The Nice Things People Say ...

"The knowledge I've gained from this information has been so valuable it has earned me a raise!" Find out more ...

Jack Bergstrom
Heavy Equipment Mechanic
Sharpe Equipment

2.   A testing problem

An automotive assembly plant installed a simple two speed circuit to advance a hydraulic cylinder at high speed and then switch to slow speed for pressing. See circuit diagram below.

However, shifting the two position solenoid valve (2) to slow pressing is causing a jolt which allows unwanted movement of the stamping. This is causing the steel stampings to be out of alignment with the bored hole in the casting.

The maintenance technician knows from experience that rapid shifting of directional control valves can cause shock. So he replaces the existing valve with a 'slow shift' version - which has a 500 millisecond shifting speed. This change only makes the problem worse.

2 speed hydraulic circuit

So the technician re-installs the original valve and installs a pressure gauge (1) connected between the rod-end port of the cylinder and the 'two-speed' solenoid valve.

He is surprised to see that pressure on the rod-end of the cylinder increases from 360 PSI to 4000 PSI when the two speed solenoid valve is energized.

The hydraulic cylinder has a 5" piston diameter and 3.5" rod diameter. The setting of the variable pump's pressure compensator is 2000 PSI.

Do you know what is causing the jolt when the cylinder changes speed and how to eliminate it? To understand this problem - and its solution, watch this video.

"This book has the potential to save many organizations lots of money. It should be on the bookshelf of every engineer, supervisor, planner and technician who deals with hydraulic equipment... it's worth its weight in gold." Find out more

Alexander (Sandy) Dunn
Plant Maintenance Resource Center

3.   Read hydraulic schematics - like an expert

A schematic diagram is a 'road map' of the hydraulic system. The ability to read and interpret one can save a lot of time and effort when troubleshooting hydraulic problems. How to Read Hydraulic Schematics was developed by JI Case to teach their technicians how to read and understand hydraulic circuit diagrams. Find out more

4. Content for your web site or e-zine

Need some fresh content for your web site or e-zine? You now have permission to reprint these 'Inside Hydraulics' articles on your web site or in your e-zine, provided:

1. Each article is printed in its full form with no changes.

2. You send an e-mail to to advise us where you'll be publishing them.

3. You include the following acknowledgement at the end of each article:
About the Author: Brendan Casey has more than 20 years experience in the maintenance, repair and overhaul of mobile and industrial hydraulic equipment. For more information on reducing the operating cost and increasing the uptime of your hydraulic equipment, visit his web site:

5. Help us spread the word

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6. Tell us what you think

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