BRAKE FLUID
Hydraulic braking systems rely on the master cylinder to create hydraulic
pressure by pumping brake fluid through the system under high pressure when
the brake pedal is applied. Brake fluid is hydroscopic in nature (meaning it
absorbs water). Thus, when a hydraulic brake system is left open to
environmental conditions, the brake fluid absorbs moisture, which finds its way
to the lowest point of the system (usually the brake calipers or wheel cylinders,
as well as the steel lines). This water causes oxidation (rust) that eats away from
the inside out, compromising system components and disabling the braking
system. Evaluate three characteristics when examining brake fluid: color,
consistency, and smell.