Hydraulic equipment : Learn from rookie mistakes


After working in the hydraulics industry for over 20 years, I’ve been fortunate enough to learn from the omissions and mistakes made by hydraulic users while dealing with the maintenance of their equipment. This article’s purpose is to hopefully give you the benefit of my experience to help you avoid the most common mistakes.

#1 Oil changing

I’ve observed people changing their hydraulic oil for many different reasons. Speaking from my own experience, there are only two conditions that can guarantee a correct hydraulic oil change.

  1. The oil level has become depleted, or the oil has degraded.
  2. Unless you can tell the actual condition of the oil, changing it for any other reason than the two mentioned above is just a waste of time and money. Removing oil that doesn’t need to be changed is simply not cost-effective. The only method I know to determine if oil needs to be changed is to perform a thorough oil analysis.

#2 Filter changes

This issue is similar to the one described above, too many operators often change their filters based on a schedule. Resulting the fact that filter change is made often too late or too early. If you change your filter too early, you are just wasting a filter. A change made too late can cause a buildup of particles in the oil; these could reduce the machine’s life service, as well as damaging its overall functioning and integrity. Filters should only be changed before the bypass valve opens and the filter itself meets its dirt holding capacity.
If you manage to do this, you’ll have to either use a crude device called the clogging indicator or a more effective method is to monitor the pressure drop of the filter regularly.

#3 Letting the equipment run too hot

Down the years, I began to get frustrated observing different operators and owners of equipment letting their hydraulic systems overheat. This is a surefire way to destroy the hoses, seals, components, and the oil itself.
So the question you’re asking is ‘how long should I let my hydraulic system run’ right ? This will largely depend on the viscosity of the oil and also the components of your hydraulic system itself.
But when oil temperature gets too hot, it’s no longer able to provide adequate lubrication because it’s viscosity has fallen. This is why the types of components installed in your system are so consequential, for example, a vane pump would require a much higher level of minimum viscosity than that of a piston pump. Putting it in simple words, you should keep the operating temperature of your oil below 82 degrees Celsius at all times.

#4 Choosing the wrong oil type

The oil you choose to use is vitally important because it directly affects the service life and performance of a machine. It’s viscosity is the major determining factor between the minimum and maximum oil temperatures levels upon which your machine’s hydraulic system operates safely.
Too many operators are entirely unaware of the fact that choosing an oil with a viscosity that is too high, or too low for the climate you’re working in, determines whether your machine has an adequate lubrication, both the coldest and hottest days of the year.
Your problems don’t end here. If the operating oil viscosity is lower or higher than ideally foreseen for your equipment, it could result in a loss of fluid friction or internal leakage. Choosing an oil with an incorrect density can cause premature failure of some of the significant components as well as an increase in the consumption of diesel or electricity. Both things a machine owner wants to avoid.

#5 Getting the filter locations wrong

Thinking that any filter is a good filter for your equipment couldn’t be further from the truth. Owners and operators are choosing filter locations that often do more harm than good and end up destroying what the filter is designed to protect. The two places where filters have no business and serve no clear purpose are on the drain line from piston motors and pumps, and the pump inlet.
There’s no need to have a filter at the pump inlet; when drawing oil from a designated reservoir there should be nothing in there that needs to be strained. Your primary concern should be to prolong your machine’s life span rather than to protect nuts and bolts unnecessarily. It’s far more beneficial to ensure that the oil is entirely and correctly filling all the pumping chambers. Hydraulic pumps are not designed to produce suction; research has shown that reducing or restricting their oil intake can reduce the machine’s service life up to 56%.
Installing a filter on a drain line causes a different set of issues. But the results will be the same causing a drastic reduction in service life on even catastrophic failures in the worst case scenarios.

#6 Hydraulic components are not self-lubricating or self-priming

It’s safe to assume that you wouldn’t knowingly start an engine whose crankcase has no oil. But you’d be amazed to see how often expensive hydraulic components are put to the same avoidable strain.
If you don’t follow a specific set of steps during equipment startup, you can seriously damage your hydraulic components. They probably will continue working for some time, but the constant wear and tear will eventually lead to premature failure.
This problem can be easily resolved, learn what you need to do and keep doing it.

#7 No basic understanding of hydraulics

The biggest issue I have observed looking back in the last decade is that people have no knowledge about how hydraulic equipment works, outside of the most basic maintenance practices. This leads eventually to a lot of time and money being wasted. Luckily all the information you will ever need is freely available online. There are no longer any excuses to avoid making the most fundamental mistakes and wasting valuable time and money. Contact us here.

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