Hydraulic Fluid Information

Hydraulic fluids are a large group of liquids made of many kinds of chemicals.
Some of the most commonly used fluids are synthetic lubricants, petroleum oils, oil-water emulsions, and water-glycol mixtures. The main characteristics of hydraulic fluid are proper viscosity, high viscosity index, anti-wear protection, if applicable, proper oxidation, proper pour point, rust inhibition, good demulsibility, foaming resistance, and compatibility with seal materials. Anti-wear oils are used in compact, high-pressure, and capacity pumps that require extra lubrication protection. They are used in auto transmissions, power steering and brakes. They are used in forklift trucks, power steering and brakes. They are used in Tractors, bulldozers, aircraft and industrial machinery.
Some common types of hydraulic fluids are mineral oil, organophosphate ester, polyalphaolefin, castor oil, silicone, glycol esters and ethers.

Hydraulic fluids can contain a wide range of chemical compounds; oils, butanol, esters (e.g. phthalates, like DEHP, and adipates, like bis (2-ethylhexyl) adipate), polyalkylene glycols (PAG), phosphate esters (e.g. tributylphosphate), silicones, alkylated aromatic hydrocarbons, polyalphaolefins (PAO) (e.g. polyisobutenes), corrosion inhibitors, etc.
Farm tractors and marine dredging may benefit from using biodegradable hydraulic fluids based upon varieties of vegetable oil since they are environmentally sensitive, and when there is the risk of an oil spill from a ruptured line. These oils are available in their designated military specifications. Hydraulic systems will work efficiently if the specific hydraulic fluid has low compressibility.
Brake fluid is a type of hydraulic fluid with a high boiling point and low freezing point.
Some hydraulic fluids have an oily smell and others have no smell. Some are flammable and some are not.