Brake fluid now is available in 3 types, these are DOT3, DOT4 and DOT5. Both DOT3 and DOT4 are glycol-based braking fluid, and DOT5 is a silicon-based fluid. The primary difference is that DOT3 and DOT4 absorb water, while DOT5 does not.
One of the more important aspects of brake fluid is its boiling point. Hydraulic systems heavily rely on incompressible fluid to transmit the force. These liquids are generally incompressible while gases are actually compressible.
If the brake fluid begins to boil (becoming gas), it will then lose the majority of its capability to transmit any force. This could completely or partially disengage your brakes. To worsen matters, the time you are most likely to boil your brake fluid is during excessive braking, such a driving downhill -- definately not the best time for your brakes to fail!
DOT3, DOT4 and DOT5
As DOT5 fluid does not absorb water. This means that the boiling point will remain quite stable, but this also means that any water that does interact with your brake system will often form pure water pockets, which could actually cause brake corrosion.
Two other very important things about brake fluid to note: DOT3 and DOT4 brake fluids eat paint, so avoid spilling either of these on your car. Also, no different types of brake fluid should ever be mixed. They can react negatively with each other and corrode your braking system.
At CAM Auto we stock 2 of the market leading brake fluid products from Ferodo and AP Racing:
Ferodo dot 5.1 brake fluid
AP Racing brake fluid
Available to buy online now at CAM Auto. Please contact us for more information