As CEO of Berendsen Fluid Power, James Leach knows more than a thing or two about hydraulic equipment. In this blog, he explains why preventative maintenance is so important – and how it can save your business time and money.

If you operate hydraulic equipment, the old saying ‘prevention is better than cure’ holds true. The leading cause of failure in hydraulic systems is contamination of the hydraulic fluid. Fact is, if you’re letting three months pass without doing any preventative maintenance (and in some situations, even less!), you’re likely to be at risk. Here’s why...

Let’s say you operate a baling press to bail scrap metal. Due to contaminated hydraulic fluid, oil starts pouring out of the cylinder gland, eventually causing the cylinder to fail. The result? An expensive repair operation to replace the cylinder, while also having to shut down the press and scrap metal piling up.

That may sound like an extreme example, but it’s more common than you’d think. Berendsen engineers are often called out to companies to fix problems with hydraulic equipment, only to find 5-10 cm of dirt in the bottom of the tank, or the tank full of water.

But the good news for maintenance managers is that there are simple steps you can take to prevent these issues. This not only helps guard your equipment from the risk of catastrophic failure, but it can also save your business time and money. In fact, around 80% of failures can be eliminated just by maintaining a clean system.

What causes contamination in hydraulic fluid?

1. Dirt – microscopic particles, either from external sources or generated within the system, become work-hardened over time, and eventually become trapped in the fine tolerances between moving parts, causing catastrophic failure.
2. Water – because systems are open to atmosphere, water vapour enters the tank and condenses into liquid water. Over time the water accumulates in the tank causing corrosion, another source of contamination.
3. Oil oxidation - this undesirable chemical reaction happens over time in all hydraulic fluid and can lead to a lacquering effect that can cause problems.

What are the essential checks to prevent contamination and other causes of failure?

There are three main preventative maintenance checks you should follow:

1. Check your oil 

Monitoring the condition of the oil in your hydraulic system is essential. You should aim to meet the oil cleanliness level stipulated in the manufacturer’s guide. This can be done by drawing a sample of the fluid and getting it tested to determine the cleanliness level and chemical balance of the fluid. However, for extra efficiency, you could consider installing an online contamination monitor to continuously measure the number and size of the contaminating particles in your system. Whenever contamination levels rise above a stipulated level, a signal is fed to a computer in the control room that will raise an alarm or automatically commence an offline filtration cycle.

2. Check your filter elements and change them out frequently

All hydraulic systems generate some type of contamination. Filters can strain out the contaminants to a microscopic level, however to work effectively they need to be checked regularly and changed out when they are clogged with dirt. Fitting them with a monitoring mechanism, a clogging indicator, is the ideal solution.

3. Check your hoses

Hydraulic hoses are made with synthetic rubber and reinforced with coiled steel. Although designed to be exceptionally heavy-duty, they don’t last forever due to the pressure at which they operate and the environment. You should check them regularly for signs of deterioration and change them after the recommended number of cycles. This ensures safety as well as reliability.

In addition, Berendsen can carry out more complicated preventative maintenance checks for you. This can include checking the pump/motor efficiency (important for avoiding damaging temperature fluctuations), checking pump couplings, system settings, and checking and re-charging accumulators.

How often should I carry out preventative maintenance?

How frequently you schedule preventative maintenance checks depends on a number of factors, including the number of hours the equipment is used each day, the working pressure in the system, the type of fluid used, the cleanliness target recommended by the manufacturer and how critical the system is to your operation.

For example, a system with an ISO4406 cleanliness target of 17/15/12 or lower, operating for eight hours a day at a pressure of less than 2000 psi (140 bar) should be checked every four months.

But a system with an ISO4406 cleanliness target of 18/16/13 or higher, operating for over eight hours a day at a pressure of more than 3000 psi (210 bar) should be checked every two months.

The manufacturer’s guide to your equipment will let you know how often you should be testing your system. In Berendsen’s experience, however, we know that it is easy to overlook these checks.

But failing to follow a regular preventative maintenance schedule runs the risk of catastrophic failure, at a considerable cost to your business – and at Berendsen, we’d hate to see that to happen to you.