What does it do?
Brake fluid is hydraulic fluid that is used in braking systems in vehicles. When the driver presses down on the brake-pedal, this applies pressure in the brake fluid lines which leads to the brake calipers closing and the brake-pads biting down on the disc rotors.
Which brake-fluid do I use?
The type of brake-fluid you use will be dependent on the vehicle you drive. Different vehicles use different types of brake-fluid, in saying this – brake fluids can be broken down into different categories based on their characteristics such as boiling points, composition and viscosity:
Is polyethylene glycol-based with a dry boiling point of 205°C and wet boiling point of 140°C.
Is polyglycol ether-based with a dry boiling point of 230°C and wet boiling point of 155°C.
Is silicone based with a dry boiling point of 260°C and wet boiling point of 180°C.
Is polyethylene glycol-based with a dry boiling point of 260°C and wet boiling point of 180°C. This is the non-silicone variant of DOT 5.
Dry boiling point – Temperature at which the brake fluid boils without moisture
Wet boiling point – Temperature at which the brake fluid boils with moisture
It is important that you use the right brake-fluid for your vehicle (you can usually find this information in your cars owner manual), using the incorrect brake-fluid type can lead to damaging the braking-system.
What does the abbreviation DOT mean?
DOT stands for the US Department of Transportation. DOT classifies each type of brake-fluid under the set standards of organizations such as the SAE (Society of Automotive Engineers) or local government equivalent. These set requirements enable standardization for brake-fluids so you can purchase brake-fluid for your vehicle anywhere in the world regardless of location or manufacturer origin and it will work.
How often should I change my brake-fluids?
Look up what is recommended by your vehicle manufacturer, but usually it is a good idea to change to new brake-fluids at the same time when you are replacing your brake-pads and disc rotors. When replacing brake-fluid it has to be bleed out completely and then topped up with new brake-fluid, this is to ensure optimal performance as brake-fluid will break down over time thus leading to a loss in performance. Also when changing fluids to is essential to not let any air into the components such as the brake lines as it will also greatly reduce brake performance.