The brake fluid is essential for the functioning of the brakes and should be changed regularly. It absorbs water, e.g. from air. Steam bubbles can form at high temperatures and impair the braking function when too much moisture is in the fluid. The absorbed water increases corrosion in the system and lowers the boiling point of the brake fluid.
It is divided into the classes DOT 3, 4, 5.0 and 5.1. Higher grades are more temperature resistant and less hydroscopic. The different classes should not be mixed. The manufacturer's recommendation must be observed. With an analysis, you can examine e.g. the water content and the boiling point of the brake fluid. The results provide information on the need for changing the brake fluid. For your information: Brake fluids based on silicone oil according to DOT 5.0 are not analysed by OELCHECK.