December 10, 2003 

'Inside Hydraulics' Newsletter

1. Troubleshooting hydraulic failures
2. The value of the humble hydraulic symbol
3. Keep up to date with maintenance and reliability issues
4. Content for your web site or e-zine
5. Help us spread the word
6. Tell us what you think


Troubleshooting hydraulic failures

Interested in obtaining maximum service life from hydraulic components, saving money and reducing downtime? Brendan Casey, will be presenting a half day workshop on troubleshooting hydraulic failures at Lubrication Excellence 2004, to be held in Nashville TN, March 21-25.

By applying the knowledge gained in this workshop, mechanics, technicians and maintenance professionals will be able to make a measurable contribution towards extending component life, reducing downtime and cutting the operating cost of their organization's hydraulic equipment.

Attendees will learn:

  • How different types of hydraulic components are constructed;
  • What causes them to fail; and
  • How to prevent these failures from occurring.

Some of the questions that will be answered during the workshop include:

  • Which filters in a system can actually reduce hydraulic component life?
  • What type of hydraulic pump is most likely to suffer a catastrophic failure as a result of cavitation?
  • What is hydrostatic balance and why is it vital in maintaining full-film lubrication between critical parts of hydraulic components?

For more information, visit the LE2004 web site or call 800-597-5460 or 918-749-1400.

2.   The value of the humble hydraulic symbol

I am regularly involved in troubleshooting problems with hydraulic equipment. In these situations, there are two things I always do before reaching for my test gear. The first is to conduct a visual inspection of the hydraulic system, checking all the obvious things that could cause the problem in question (never overlook the obvious). The second is to ask for the schematic diagram for the hydraulic circuit.

What is a hydraulic schematic diagram?

A hydraulic schematic diagram is a line drawing composed of hydraulic symbols that indicate the types of components the circuit contains and how they are interconnected.

What makes a hydraulic schematic diagram valuable?

A schematic diagram is a 'road map' of the hydraulic system and to a technician skilled in reading and interpreting hydraulic symbols, is a valuable aid in identifying possible causes of a problem. This can save a lot of time and money in a troubleshooting situation.

If a schematic diagram is not available, the technician must trace the physical circuit and identify its components in order to isolate possible causes of the problem. This can be a time-consuming process, depending on the complexity of the system. Worse still, if the circuit contains a valve manifold, the manifold may have to be removed and dismantled - just to establish what it's supposed to do. Reason being, if the function of a component within a system is not known, it can be difficult to discount it as a possible cause of the problem. The humble hydraulic symbol eliminates the need to 'reverse engineer' the hydraulic circuit.

Where are all the hydraulic schematic diagrams?

As most hydraulic technicians know, there's usually a better than even chance that a schematic diagram will not be available for the machine they've been called in to troubleshoot. This is unlikely to bother the technician because it is the machine owner who pays for its absence.

Where do all the hydraulic schematic diagrams go? They get lost or misplaced, they don't get transferred to the new owner when a machine is bought secondhand and in some cases they may not be issued to the machine owner at all. Why? Because generally speaking, hydraulic equipment owners don't place a lot of value on them.

So if you're responsible for hydraulic equipment and you don't have schematic diagrams for your existing machines, try to obtain them - before you need them. And ensure that you are issued with schematic diagrams for any additional hydraulic machines you acquire. It will save you money in the long run.

"This book has the potential to save many organizations lots of m0ney. It should be on the bookshelf of every engineer, supervisor, planner and technician that deals with hydraulic equipment... it's worth its weight in gold." Find out more

Alexander (Sandy) Dunn
Plant Maintenance Resource Center

3.   Keep up to date with maintenance and reliability issues

If you're involved in the maintenance of hydraulic or any other type of rotating machinery, it's essential to keep up to date with maintenance and reliability issues. Machinery Lubrication magazine contains practical articles on lubricant selection and application, contamination control, filtration and condition-monitoring of hydraulics, engines, transmissions, gearboxes, compressors and other types of rotating machinery. To receive a complimentary subscription to this informative magazine (US and Canada only) go to:

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 let us know where you'll be publishing them.

3. You include the following credit at the end of each article:
About the Author: Brendan Casey has more than 16 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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