Brake fluid

Brake fluid is a type of hydraulic fluid used in hydraulic brake and hydraulic clutch applications in automobiles, motorcycles, light trucks, and some bicycles. It is used to transfer force into pressure, and to amplify braking force. It works because liquids are not appreciably compressible. Most brake fluids used today are glycol-ether based, but mineral oil (Citroën/Rolls-Royce LHM as well as Shimano and Magura bicycle brake fluid) and silicone-based (DOT 5) fluids are also available. The origins of modern braking systems date back to 1917, when Malcolm Lockheed patented a hydraulic actuated braking system. Initially, vegetable oil was used as a working fluid. But it did not meet the most basic requirements, and in the process of evolution, special brake fluids were created, which consist of a base and a package of additives (thickeners, anti-corrosion additives, colorants). Most brake fluids are manufactured to meet standards set by international, national, or local organizations or government agencies. The International Standards Organisation has published its standard ISO 4925, defining classes 3, 4, and 5, as well as class 5.1, class 6 and class 7 reflecting progressively higher performance for brake fluids. The Society of Automotive Engineers SAE has published standards J1703, J1704, and J1705, reflecting progressively higher performance for brake fluids.