What can a technician use to assess the quality of brake fluid?

A brake fluid tester is specifically designed to measure the moisture content in brake fluid, which is crucial for assessing its quality and performance. Brake fluid is hygroscopic, meaning it can absorb moisture from the air over time. This moisture can lower the boiling point of the brake fluid, leading to brake fade and decreased braking efficiency, which can endanger vehicle safety. Using a brake fluid tester allows a technician to determine if the fluid has absorbed too much water and whether it needs to be replaced, ensuring the braking system functions optimally.

While other methods could provide some insights into the brake fluid's condition, they don't directly measure the critical parameters that affect its performance as accurately as a brake fluid tester does. For example, using a metal stick to feel for viscosity would not yield reliable data, as viscosity can be affected by many factors and is not a standard measure for assessing fluid quality. Similarly, a thermometer used to measure temperature wouldn’t directly indicate the fluid's degradation or performance and would only provide environmental information. A color chart might help identify some degradation or contamination in the fluid based on appearance, but it's not a definitive measure of moisture content or other chemical properties that affect braking capability.