Toro 99051SL Manuel D’Utilisation

Hydraulic Oil Filters

Toro Hydraulic Filters 

•  Filter Mounting Base 

–  Rigid Cast Base 

•  Filter Element Seal 

–  Positive Rubber seal 

–  Captive in the Filter Element 

•  Bypass Valve 

–  None for Hydraulic Filter 

–  Needs Complete Filtration 

•  Filter Element 

–  Steel Ends 

–  Glued on Ends 

–  Proper Micron Rating 

•  Spring (coil) 

–  Resists heat related 

Deformation 

“Will Fitter” Hydraulic Filters 

•  Filter Mounting Base 

•  Filter Element 

–  Stamped Steel 

–  Glued on Ends 

–  Can Flex

–  Uneven Gluing 

•  Filter Element Seal 

–  Proper Micron Rating ? 

–  Rubber seal 

•  Spring (Wafer) 

–  Non-Captive 

–  Susceptible to heat related 

–  Not a positive seal 

Deformation 

•  Bypass Valve 

–  Some have Bypass valves 

–  Allows unfiltered oil to

bypass

Micron Rating vs Beta Rating 

•  Rating of the Particle Size 

Stopped by the Filter 

–  Nominal rating 

•  Removes Approx. 80 % of 

particles larger than rating. 

–  Absolute 

•  Removes all particles larger then 

rating. 

–  Based on media hole size. Can 

vary widely 

–  Not Based on Actual Filter 

Performance 

•  Based on actual filter Efficiency. 

•  Rates the Filters Ability to 

Capture Various Size Particles. 

A typical quality hydraulic filter will have a rigid 
cast base. 

The filter seal will be a rubber seal, which is 
captive in the end of the filter. 

Most Toro hydraulic filters will not have a bypass. 
The bypass will allow unfiltered oil to flow past the 
filter and back into the reservoir. 

The filter element will have steel ends and it will be 
fully glued on the ends. 

The paper will also be the proper micron rating. 

And the spring will usually be a coil spring.  This 
type of spring resists heat deformation 

Some cheaper filters may have a stamped steel 
base.  This type of base can flex and leak. 

The filter element seal may be a non-captive seal. 
Under higher pressure situations this type of seal 
may leak. 

The filter may have a bypass valve.  This may be 
because this filter is used in several applications, 
some that require a bypass valve. 

The filter element may or may not be glued on the 
ends.  The gluing may be uneven. 

The micron rating of the filter element may not be 
correct. 

The filter may even be equipped with a wafer type 
spring.  This type spring can change tension 
greatly under different temperatures 

There are two ways to rate filters. 
Micron ratings and Beta ratings. 

With Micron ratings there are two sub ratings. 

A nominal rating captures approximately 80% of 
the particles larger then the rating. 

A filter with an absolute rating removes all the 
particles larger then the rating. 

Micron ratings are based on the hole size of the 
media.  It is not based on the actual filter 
performance. 

Beta Ratings are based ion the actual filter 
performance.