Preventative maintenance essential for hydraulic systems

One of the major causes of hydraulic failure is contamination in the hydraulic system.

Some estimates hold that 75% of failures can be traced back to contaminated or aging hydraulic fluid, while others claim that 80% are due to contamination alone. However, you can minimize contaminants from infiltrating your system.

There are preventative steps you can implement in your existing preventive maintenance for hydraulic systems plan to minimize the impact of air and water, as well as steps you can take to mitigate existing damage.

The first level of defence against contamination involves filtering all hydraulic fluid before it is added to your system. As mentioned earlier, even new hydraulic fluid will contain some level of contamination, and more modern hydraulic system components can be damaged by this contamination even though it may seem insignificant. Filtering fresh hydraulic fluid is a must.

The second level of defence against hydraulic contamination is regularly checking and replacing the hydraulic filters in your system. Waiting until the manufacturer’s recommended date for replacing them may be too late – the filter may have become clogged which eventually causes the fluid to bypass it. On the other hand, replacing them too soon is a waste of money that could be used elsewhere.

Another important aspect of dealing with filters is making sure that the filters installed are the proper ones (e.g., the correct micron rating and type) and that they are high quality components. Cheap filters may seem attractive for saving money, but in the long run they will cost much more. Keep in mind that when a cheap filter fails, it can do serious and expensive damage to the hydraulic system. Although not normally considered part of the filtering on a hydraulic system, the installation and checking of desiccant breathers is also a good preventative measure. OEM breather caps and dust caps can allow moisture to enter the system, whereas a desiccant breather has multiple layers of desiccant material to absorb moisture before it makes its way into the system. In addition, these breathers are much better at preventing fine dust from infiltrating the system. The third level of defence against hydraulic system contamination is the practice of cleanliness during maintenance and repairs. The system should not be opened up to the atmosphere except when necessary, and it should not be left open without good reason. This prevents ingression of moisture and air, as well as dust. If the exterior of the system is dirty, it should be cleaned at least in the immediate area of where the repairs are to be made. When hydraulic hoses are disconnected, both the hose and the port should be plugged immediately. Repairs and disassembly should always be performed in a clean workspace, and only lint-free cloths should be used.

The fourth level of defence against contamination is to address any leaks as soon as they are detected. If hydraulic fluid is able to make its way out of the system, then contaminants can also get inside the system. This is especially true when leaks can be traced back to failed seals and brackets or a leaking bearing.

Preventive maintenance for hydraulic systems is critical for hydraulic equipment, whether it is an industrial system running in an enclosed plant or an integral part of a powerful hydraulic excavator. One of the major factors behind the failure of hydraulic systems is contamination. If contamination has already become a problem, there are definite steps that can be taken to mitigate the damage. Preventive measures, including the correct use of filters and hydraulic fluid analysis, should be a part of every comprehensive hydraulic maintenance plan.