What should be the primary concern when adding brake fluid?

When adding brake fluid, the primary concern should be the potential for contamination. Brake fluid is a hydraulic fluid that plays a crucial role in the braking system, and it is highly sensitive to contamination from moisture, dirt, or other fluids. Any contaminants introduced into the brake fluid can compromise the performance of the braking system, leading to issues such as corrosion within brake components, air bubbles in the hydraulic system, or a decrease in the boiling point of the fluid.

Maintaining the purity of brake fluid is essential to ensure reliable brake performance and safety. Contaminated brake fluid can also lead to brake system failure or diminished braking efficiency, which poses significant risks on the road. Therefore, it's vital to use the correct type of fluid specified by the vehicle manufacturer and to avoid introducing any foreign substances during the fluid addition process.