Maintenance best practice: looking after your hydraulic filters

Like any piece of equipment, filters perform best when they are in a system that is well maintained and looked after.

Including hydraulic filters as part of your scheduled preventative maintenance plan can prolong the life of the machine and filter, maintain peak performance, prevent unscheduled downtime and protect operators. Not only will a maintenance programme help look after your machine or power-pack, but it can also mean issues are spotted early before they cause major, and costlier, problems.

Which filters can be cleaned?

There are three main types of media used to make hydraulic filter. Paper or Cellulose, which is 50% efficient; glass fibre, which is 99.9% efficient; and wire mesh.

How to clean a wire mesh filter

Due to the nature of the media used to make the filter, only wire mesh filters can be cleaned. To do this, submerge the wire mesh in a bath filled with mild detergent and warm water. Rinse the filter with clean water and gently scrub the filter with soft nylon brushes. Keeping the filter submerged in the detergent can help remove more stubborn contaminants.  

Regular maintenance is the key

It is crucial in a modern engineering facility that you have a detailed schedule of planned preventative maintenance. This should establish an appropriate frequency for changing filters. However, should a filter become wet, if there is visible microbial growth, or if it collapses or becomes damaged to the point that the hydraulic fluid is bypassing the element unfiltered, or worse not passing through the media at all,it should be changed regardless.

In metalworking, good filtration can prolong the life of cutting fluid. Ensuring that sump is regularly cleaned using the appropriate detergents can also help prolong the life of a filter as it reduces the possibility of it becoming blocked with tramp oil and other undesirable by-products of the cutting process.

Many production facilities use a clogging or bypass indicator on machinery. They measure the pressure in the machine and are designed to give a visual indication of when a filter needs to be cleaned or changed. When the pressure reaches a certain point, the indicator will change from green to red, if it is not electronic, to show that that fluid is no longer being filtered and is bypassing the filter. Without action being taken, all manner of waste products can enter the system and potentially cause it to break down.

When it comes to changing filters, we recommend making the job as easy as possible. If possible, place labels on the housing units with information such as the element number and filter type, the date last changed, and the pressure drop. This information can make a maintenance engineer’s job far easier.

At FilterFinder, we advise changing filters every six months. However, that does depend on the filter, what is being filtered, and how dirty the system is. The important thing is to have a consistent, planned maintenance regime in place, and make sure machine filters form part of that regime.


When it’s time to change your hydraulic filters, FilterFinder makes finding the right replacement filter easy. Simply type the element/filter number that you will find on the housing or end-cap into the search bar on our website and you will find the filter you need.