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Hydraulic Filters

Today, there are a lot of hydraulic filter suppliers currently manufacturing or selling filters for turf mowing equipment. First, let's look at the filter system failures themselves. It's believed that over 75% of all hydraulic system failures are a direct result of contamination. And if the oil is contaminated to the point that it needs to be replaced early, that too will add to unnecessary operating costs. Cost from lost production and replacing failed components can be avoided by properly maintaining the equipment and keeping the hydraulic oil clean.

Contamination in the oil can inhibit the four main functions of oil:

  • The oil is what actually transmits the energy (work) through the system.
  • The oil has to lubricate the system.
  • The heat in the hydraulic system is carried away and dissipated by the oil.
  • The oil will seal the small clearances in the hydraulic system.

Contamination, be it water, dirt or metal, will limit the oils ability to perform these functions.

The worst oil filter leak is an internal leak. An internal leak occurs when oil bypasses the filter element seal and flows throughout the system without passing through the filter element. Because no oil drips from the filter, the operator does not know there is a problem until it's too late. You may disagree and say that an external leak is worse since dripping oil can damage grass.

Remember when you buy cheaper filters the only way will-fit manufacturers can cut costs is through the cost of materials - not labor. (About 90-95% of the cost of a filter is in the material.) It only stands to reason that cheaper filter components don't work as well as the higher quality filter components found in Toro hydraulic filters. The bottom line: The only way to build a cheaper filter is to use cheaper materials.

One of the biggest issues in filters - especially in low-micron filters - is that there will be a fair amount of system back-pressure. The more back pressure there is, the more stress there is either internally within the filter or between the filter and the mounting base itself.

Nobody knows better than Toro engineers the exact level of cleanliness that needs to be specified for Toro hydraulic components and parts.

Will-fit filters are generally designed to fit several different machines. Toro only specifies the appropriate filter for the machine.

Here are the key points about Genuine Hydraulic Filters:

  • Cast Base  Most Toro hydraulic filters feature a rigid cast base while will-fit filters may use a stamped steel design that can flex. Flexing can lead to filter leakage and contamination.
  • Captive Rubber Seal  Most Toro filters include a captive rubber seal in the end of the filter. Will-fit filters can be made with a non-captive rubber seal. Under higher-pressure situations this type of seal may weaken and leak.
  • Bypass Valve  Most Toro hydraulic filters will not have a bypass since the bypass will allow unfiltered oil to flow past the filter and back into the reservoir. Some will-fit filters may have a bypass valve so the filter can be used in several applications including some that require a bypass valve.
  • Glued Ends  The Toro filter element includes steel ends and will be fully glued on the ends. Will-fit filters may or may not be glued on the ends or the gluing may be uneven which could result in filter failure.
  • Specifications  Toro specifies filters based on what is the best size for this system to maintain the life of the machine. Will-fit specifications specify filters based on what additional applications can this filter be used for to save customers money. Will-fitters want the filter to be "close enough." Toro wants it to be right.
  • Coil Spring  Toro hydraulic filters will usually include a coil spring which resists heat deformation. Will-fit filters may be equipped with a wafer type spring, which can greatly change tension under different temperatures.
  • Micron Rating  Toro filters use the exact micron rating for the application while will-fit filters may not have the correct micron rating. Proper hydraulic filter sizes are based on Toro engineers' specifications. Each filter is designed to accommodate the expected oil temperature, surges and the system back pressure. Toro filter sizes are specified to trap 100% of the rated particles. Will-fit filters are usually specified to trap just 80% of the particles.
  • Micron Rating versus Beta Rating  There are two ways to rate filters: Micron ratings and Beta ratings. Micron ratings are based on the hole size of the media; they are not based on the actual filter performance. Beta ratings are based on the actual filter performance.
  • Sub Micron Ratings  With Micron ratings there are two sub ratings - nominal and absolute. A nominal rating captures approximately 80% of the particles larger than the rating. A filter with an absolute rating removes all the particles larger than the rating.
  • Beta Rating   The Beta rating will consist of two numbers. The first number is the filtration ratio and the second number is the particle size (in microns).
    An example of a typical Beta rating is:
    2/2 Equals 50% of the 2 micron particles
    20/3 Equals 95% of the 3 micron particles
    75/5 Equals 98.6% of the 5-micron particles.
    It's important to know these equations when comparing Toro filters with similar will-fit filters that generally don't have as high of performance ratings.
  • Particulate Contamination
    Common particles and their micron size
    Particle Micron Inches
    Table Salt 100 micron .0039 inch
    Human Hair 70 micron .0027 inch
    Blood Cells 25 micron .00158
    Talcum Powder 10 micron .00039 inch
    Bacteria 2 micron .000078 inch

    Why is filtering so critical? To give an example, some of the clearances in the hydraulic system of Toro units can be as tight as .0004 to .0009. Contamination in the oil can adversely affect the performance and reliability of the hydraulic components and this will affect the overall performance of your Toro product.