Service Bulletin

Hydraulic System Fluid Recommendations
Toro equipment is designed and tested with the most appropriate type of hydraulic fluid for
the specific application. The type of fluid selected is based on a variety of factors, such as:
1) Hydraulic component manufacturers recommendations
2) Toro testing and experience
3) The availability of the fluid type throughout the world
4) Product application demands
The system fluids most commonly used in hydraulic-driven equipment are petroleum-based
products. These fluids serve users well at a reasonable cost. These conventional
hydraulic fluids provide adequate lubrication, corrosion protection, and performance
characteristics for the various types of hydraulic components in mobile equipment -
cylinders, motors, pumps, etc. Another important factor is that seal materials have also
been developed and tested to be compatible with these same petroleum-based fluids.
The hydraulic fluid recommendations in each Toro equipment Operator’s Manual describes
appropriate lubricants for the model identified on the manual cover. Most Toro equipment
requires a high viscosity index/low pour point, anti-wear hydraulic fluid with a multi-grade
viscosity rating (ISO 46 M). A few select machines use Universal Tractor Hydraulic Fluid
(UTHF) which has different material specifications. Both of these types of fluids are
petroleum-based mineral oils. Specifications are listed later in this document.
Toro also recognizes that some customers have an interest in a biodegradable fluid for
environmental reasons and a shortened recovery timeframe in the event of a leak on the turf.
Toro has tested and now offers a vegetable-based Biodegradable All-Season Hydraulic Fluid
which can be used in many, but not all of our products. The Groundsmaster
®
580-D and
Reelmaster
®
4000 series mowers are examples of machines which cannot use a
biodegradable fluid due to the extreme heat and pressure associated with the application.
The testing completed to approve these biodegradable fluids involved a considerable
amount of lab and field testing to verify the suitability of this fluid for Toro equipment,
including all the system components and operating conditions that are encountered.
Biodegradable Fluids in general: Biodegradable fluids must pass certain tests to assure
they will not break down or otherwise cause harm within the product or natural environment
of the application. Some of the general fluids available for sale to customers have good
lubrication properties while others may not. Be aware that there are distinct advantages in
using the fluids The Toro Company has approved. It is possible for moisture, extreme
pressures, and heat created in the hydraulic system to affect unapproved fluids, resulting in
accelerated wear due to inadequate lubrication. Failure analysis of such damage has most
often revealed that “lack of lubricity” or “lack of lubrication” has been the mode of failure.
This type of failure requires “expert” diagnosis because it can easily be misconstrued as
other types of component failure/damage which in turn leads to improper conclusions as to
the actual root cause. Oil seals may also be incompatible with the additives used in some
fluids which may cause the seals to deteriorate and fail prematurely.
The Toro Company will not be responsible for the consequences of using unapproved
hydraulic fluids, or those that do not meet the biodegradable specifications identified in the
following standards. Charts such as this will be included in all future Operator’s Manuals.