Whether your industry is transportation, construction, marine, manufacturing, or any other field that depends on hydraulics, you know that hydraulic contamination is a major issue. The more you know about fluid contamination – including types, sources, and prevention – the better position you are in to keep your hydraulic equipment running efficiently and to save money on repair costs.

Different Types of Hydraulic Contamination

The definition of hydraulic contamination is quite simple: it is foreign matter that is found in hydraulic fluid. Sometimes contamination is easy to spot, like when it consists of particles of rust or slivers of metal. More often than not it cannot be seen by the naked eye. Regardless of whether it is visible or not, contamination can severely damage hydraulic systems and components.

Experts have different ways of classifying types of hydraulic contamination, and one of the easiest involves this simple question: Is the contamination abrasive? Abrasive contamination involves particles, such as a few grains of core sand left over from casting, small flakes of rust that fell into the system during routine servicing, or weld spatter that was introduced before the equipment ever left the manufacturer.

Non-abrasive contaminants are just as damaging as abrasive contaminants. They can include particles, such as the remnants of shredded elastomeric seals from a pump, or chemicals, such as the byproducts resulting from the oxidation of the oil or the result of reactions involving additives. While not abrasive, these contaminants can still have an extremely negative impact on the hydraulic performance of motors and pumps.

Recognizing the Sources of Fluid Contamination

There are many sources of hydraulic contamination, and oftentimes it starts during manufacturing of the hydraulic fluid. Fluid manufacturing companies often have little control over how the fluid is processed and handled before it makes its way to the customer. This opens the possibility that even brand new fluid can be contaminated. Before adding fluid to any hydraulic system, machine, or components (including reservoirs, pumps, valves and motors), it should be carefully filtered through a fluid servicing cart/unit. Be aware that contamination can also occur when fluid is added to the hydraulic system or being transferred.

Even new equipment and components can be contaminated. Whether it’s a new valve or hydraulic motor (or any other system components found in between), contamination may already be built in, either during manufacturing or during assembly. Slivers of Teflon sealing tape, smears of grease, tiny particles of weld spatter, or a thread from a rag can be found in brand new hydraulic systems and components.

Some contamination will develop during normal operation, and this often includes the non-abrasive chemical contamination discussed earlier. Chemical reactions can occur as the hydraulic fluid ages or is exposed to higher temperatures than it was originally designed to handle. In addition, physical damage to hydraulic components, such as the rotating group in a hydraulic motor or failed bearings in a hydraulic pump, can generate the abrasive type of contamination that is lethal to hydraulic systems.

Testing for Hydraulic Fluid Contamination the Smart Way

For hydraulic equipment to remain healthy, it should be regularly tested for contamination according to the manufacturer’s recommendation. In addition, contamination checks should be run whenever contamination is suspected, or when the system has been operating at unusually high temperatures. A thorough contamination check involves taking more than one sample of the hydraulic fluid:

• First, take a sample in accordance with manufacturer recommendations from the fluid reservoir.
• Next, take samples at other locations besides the fluid reservoir. This allows you to track down the source of the contamination so that it can be addressed.
• Failure to address the cause of the hydraulic fluid contamination only delays the inevitable breakdown and increases the cost of repairs, whether it’s a simple hydraulic motor at a food processing plant or a complex hydraulic system used in manufacturing.

Preventing Hydraulic Contamination

The first step in preventing hydraulic contamination is filtering. All fluid should be filtered through a fluid service cart or unit before it is introduced to a hydraulic machine or any hydraulic components. The next major line of defense against hydraulic contamination is filters. Filters should be checked, cleaned, and replaced per manufacturer guidelines. Cheap, low-quality filters should never be used – always use the filters recommended by the manufacturer. Filters should be left inside their packaging until immediately before installation and handled carefully in a clean environment to reduce the chance of contamination.

When hydraulic fluid is to be flushed, take samples before draining the original fluid and after installing the new fluid. Also, remember that both filters and fluids may need to be changed more often based on the results of fluid analysis and testing.

Hydraulic contamination can also occur during routine servicing or repairs. The chances for contamination can be minimized by using common sense and working in a clean environment. Workbenches, tools, and any servicing equipment should always be kept clean. Only lint-free cloths should be used.

Anytime hydraulic fittings or lines are going to be disconnected, clean the immediate area with a dry solvent. Use dust caps on the ends of couplings when they are not in use. Always clean the couplings and ends of hydraulic hoses before installing them. In fact, all components should be cleaned in an approved dry solvent, dried (with a lint-free cloth, as needed), and then lubricated before assembly takes place.

Let MAC Hydraulics Keep Your Hydraulic Systems Up and Running

MAC Hydraulics can relieve your hydraulic contamination concerns by bringing our state-of-the-art mobile equipment to your facility to perform maintenance and repairs. From simple tasks like hose replacement or preventative maintenance to more complex tasks such as hydraulic system troubleshooting, we can handle your hydraulic equipment needs in a timely fashion, minimize your costly downtime, and provide you with high quality service that is unmatched by our competitors. Contact us today for more information.