19/07/2017 3:35pm
Because it lowers the boiling point, increases compressibility and increases corrosion. Modern brake systems are designed to help reduce the amount of heat that transfers from the pads and discs to the calipers and brake fluid, but it can only ever reduce it. Fundamentally, brakes work with friction and friction creates heat. If you introduce enough heat then eventually the fluid will boil. This creates air bubbles and air bubbles are compressible. This means that when you pull the brake lever, instead of transmitting the pressure to the pistons, the pressure compresses the bubbles instead and the pistons move very little or not at all. So, you pull the lever, nothing happens and you arrive at the corner with full speed and no brakes what so ever. Been there, done that, don’t want to do it again! The other problem is corrosion. The water allows the internal components to corrode and this creates an inefficient system which leads to component replacement or a seriously impaired system.