Hydraulic fluid for a bobcat

Hydraulic fluid for a bobcat: Selecting the right hydraulic fluid for your skid steer, track loader, mini excavator or other compact equipment is quite easy – just follow the manufacturer’s recommendations.

You will find recommendations in your equipment owner’s manual. John Deere, for example, fills its 36G mini excavator with Super EX 46HN extended life zinc-free hydraulic oil and warns against mixing brands.

“Oil manufacturers design their oils to meet certain specifications and requirements,” the John Deere manual says. “Mixing different oils can degrade lubricant and machine performance.”


That doesn’t mean you can’t use a manufacturer’s brand equivalent oil in your machine. But keep in mind that while different brands of oil are similar, they may not contain the precise additives needed for optimal performance.

John Deere also includes a table listing recommended oil viscosities based on air temperature. A premium anti-wear (AW) 46 oil, for example, has a temperature range of 14 to 104 degrees F, while Deere’s Super EX 46HN has a temperature range of -4 to 104 degrees F. For low-temperature operation , Deere recommends their zinc-free Daphne Super Hydra A 32 (-22 to 86 degrees F) or an equivalent AW 32 premium oil.

Viscosity and temperature range are important factors to consider when choosing a hydraulic fluid. Overheated oil forms varnish, causing valves and other components to stick, resulting in poor equipment performance.

When it comes to biodegradable oils, John Deere recommends using only Exxon Mobil EAL Envirosyn 46H synthetic ester oil and suggests contacting your John Deere dealer for routine oil analysis to meet warranty requirements. The company advises emptying and refilling the oil in the mini-excavator’s hydraulic tank every 2,000 hours. And be sure to properly dispose of all used oil and filters.

Bobcat recommends using its own brand all-season hydraulic/hydrostatic fluid. The oil is designed to provide optimum flow in sub-zero temperatures, while maintaining stability during periods of high-temperature use. The company says its oil cannot be duplicated by commercially available fluids. Bobcat also offers a synthetic hydraulic/hydrostatic fluid for improved cycle times, increased work performance and smoother operation, as well as an environmentally friendly, biodegradable hydraulic oil with anti-wear additives and corrosion protection for equipment built after 2004.


So what exactly is hydraulic fluid?

Its main purpose is to transfer energy over distance. The other job of hydraulic fluid is to protect against wear, rust, and corrosion, as well as cool and clean internal components.

Most hydraulic fluids are formulated from molecularly reformulated synthetic or hydrocarbon base oils. Some environmentally friendly biodegradable hydraulic fluids may be plant-based, while fire-resistant hydraulic fluids may even be water-based.

Due to small tolerances in equipment components, it is important to keep the hydraulic fluid clean.

“Dirt is the real enemy. Microscopic dirt will also wear it down,” says Bruce Coleman, co-owner of Coleman Equipment, a dealer for Case and Kubota equipment, based in Kansas and Missouri. “Keep the system as clean as possible, especially if you are using hydraulic couplers. At least clean the damn stuff before you plug anything in so you don’t ingest a certain amount of gunk into your system.”

Chris Barker, technical services manager for Royal Purple, maker of commercial-grade synthetic lubricants, says it’s always best to follow OEM recommendations when selecting a hydraulic fluid.

“First, make sure if you’re replacing a fluid you’re using the same type,” he says. “Next, you need to look at the viscosity grades that are recommended.”


Most industrial fluids use the ISO viscosity grade scale instead of the more common SAE grades: 20, 30, 40, 5W-30, 10W-40.

“In the past, most hydraulic fluids were SAE 20, but they had a very wide range of viscosity possibilities,” says Barker. “ISO viscosity grades reduced that. The most common hydraulic oil viscosity grade in the ISO category is 32, 46 and 68. And they all fall within the SAE 20” range.

One way to ensure that the hydraulic oil you are using is working properly is to perform an oil analysis.

“A proper oil analysis program will show you the wear metals that are generated, the contaminants that get into the oil, as well as the changes that happen to the oil,” he says. “For that to be significant, it has to be a trend so you can see what happens over time. An oil analysis of a particular gearbox doesn’t tell you much.”

An oil analysis can cost $15-$20 per sample at a consumer lab or $25-$30 at a commercial lab. While both can do an adequate job, Barker recommends using a commercial lab due to the accuracy and detailed information provided.


When storing unused hydraulic fluid, make sure the package is intact and the closure or cap is secure, Barker says.

“Keep the temperature relatively constant. Don’t store it in direct sunlight and don’t let it rain,” he says. “The best case scenario is to keep it in a climate controlled environment. Large temperature swings can cause packaging to breathe, pushing hot air out and cold air in.”

Ambient air contains numerous pollutants; the most common is moisture.

“Dry oil is the best oil,” Barker says. “When you get water into the oil and get it into the equipment, you increase the risk of corrosion and degradation.”

Remember, the life of your machine is in the oil. Be sure to change it.

Choosing the right fluid for hydraulic systems


Hydraulic fluid is the most important component of a hydraulic system. Choosing the right hydraulic fluid is crucial to ensure the best system performance and efficiency. Each fluid has its specific characteristics in terms of viscosity, proper operating conditions, anti-wear properties, etc. In this article we offer valuable tips and tricks for selecting the right fluid for your hydraulic system.

Hydraulic fluid (HF) is a crucial element in any hydraulic system because it influences important performance parameters such as power transmission, lubrication, heat dissipation, debris transport, contamination and sludge formation.

To select the best hydraulic fluid you must take into account the operating conditions and the requirements of your system. In addition, you must take into account the applicable environmental and safety conditions and regulations.

How Hydraulic Oils Affect Your System Performance

The fluid and the components of a hydraulic system are one. Together they determine the efficiency and lifetime of the system. The critical elements of a hydraulic fluid are fluid type, viscosity, and quality.

A hydraulic system that works with a bad combination fluid suffers from:

  • decreased efficiency,
  • lack of lubrication,
  • reduced component life,
  • corrosion, sludge and varnish,
  • heat generation

In addition to fluid properties, the level of contamination is equally crucial to system performance and wear resistance of the pump and components.

The viscosity of hydraulic fluids is key

Although various fluid properties have an impact on different performance functions, the viscosity of the hydraulic fluid is a key element. Fluid viscosity affects hydraulic systems in several ways:

  • volumetric efficiency (= efficiency in relation to volume loss due to internal leakage),
  • mechanical efficiency (= efficiency in relation to mechanical loss due to internal friction),
  • (elasto)hydrodynamics and boundary lubrication,
  • cavitation,
  • heat dissipation,
  • air Release,
  • filterability,

The optimum operating range of a hydraulic system is highly dependent on the viscosity of the fluid.

If heThe viscosity of the hydraulic fluid is too low., the oil film will be too thin and will cause direct metal-to-metal contact, resulting inexcessive component wear. Low viscosity fluids also increase the risk of internal leakage creating alower volumetric efficiency of pumps and motors.

If hefluid viscosity is too high, the system will suffer from slow motion and areduction in mechanical efficiency. It generatesenergy losses Yunnecessary heat generation. Other negative effects of high fluid viscosity are cavitation, poor air release, and inadequate lubrication.

HF viscosity is influenced by ambient and operating temperatures and system design. High temperatures result in lower viscosity and vice versa. Choosing a hydraulic fluid with the correct viscosity is paramount to the overall efficiency of the hydraulic system. Fluid viscosity determines both mechanical efficiency and volumetric efficiency and sets the limits of the optimal operating range of a hydraulic system.

How to choose the right hydraulic fluid?

When it comes time to change or refill the hydraulic fluid in your system, it’s absolutely crucial that you make the right choice if you want to be able to trust your system and ensure it’s running efficiently. However, many people feel insecure about how to choose among all the hydraulic fluids for fear of unexpected downtime and breakdowns. We know that choosing the right fluid for your hydraulic system can seem quite complex, but it doesn’t have to be that difficult.


Start by seeing if you have any documentation showing the required hydraulic fluid specifications, and if you do, it makes the whole process much easier. If you don’t have that information, you should consider where and how the hydraulic fluid is used. For example, is it used indoors? Or are you exposed to outdoor temperature fluctuations? If you want to use an environmentally classified product, you must use a hydraulic fluid based on synthetic esters. Many companies would benefit from doing this, as today they often provide energy savings with a smaller environmental footprint, as well as better technical properties than conventional mineral oils.

If you find this post of hydraulic fluid for a bobcat helpful to you and you want to know more about car fluid knowledge, please check more on our website Auto Oil And Fluid. Thank you for your interest!



Rate this post