Brake fluid composition

Brake fluids are composed of 3 mains components

SOLVENT 60 to 90%

Polyglycols have a high viscosity that is why it is necessary to dilute them with a product with low viscosity (polyglycol ethers).
Polyglycols ethers ensure the role of solvent in the fluid. They have to dissolve polyglycols and all other components in such a way to obtain a single-phased fluid to provide satisfactory lubrication under all temperatures.

LUBRICANT BASIS 5 to 30%

Polyglycols are used as lubricants in proportion of up to 30% in brake fluids.
They are obtained by reacting alkylene oxides (ethylene and propylene) with bifunctional components such as diols or water.

ADDITIVES 2 to 5%

Brake fluids usually contain up to 5% of additives.
Corrosion inhibitors are added to protect the brake system metals from corrosion and antioxidants are needed to reduce the oxidative decomposition of glycol ethers polyglycols and to retard the formation of acidic decomposition products and resins.
These two inhibitors' types are essential to ensure a long-term and satisfactory brake fluid service life.