Properties of brake fluid
1) Boiling point: Boiling point of fluid must be high because due to continue operation of brakes, generates the heat inside the drum, which increases the temperature of fluid in the wheel cylinder and lastly generates the vapour, which decreases the effectiveness of brakes. Therefore the boiling point should be high i.e. 25000 C to 30000 C.
2) Viscosity: Viscosity of brake fluid should be such that the fluid should not lose its fluidity in any atmospheric condition. i.e., too cold or too hot temperature.
Therefore, it is necessary that the viscosity of brake fluid should change adequately with the change in temperature to maintain its fluidity.
3) Lubrication properties: The brake fluid should provide proper lubrication to the pistons in the master cylinder, wheel cylinder. Otherwise these components wear out quickly.
4) Effect on rubber: A number of rubber seals are used in the hydraulic braking system, therefore the brake fluid should not have any effect on these seals. Otherwise it leads to leakage of fluid, loss of pressure in lines.
5) Corrosive action: The brake fluid should not corrode the metal components with which it comes into contact.
6) Storage stability: Brake fluid should have sufficient stability at least 3 years.
During this period the fluid should not be spoiled.