What does a brake fluid tester measure?

A brake fluid tester is specifically designed to assess the condition of brake fluid by measuring two critical factors: moisture content and fluid boiling point.

Moisture content is important because brake fluid is hygroscopic, which means it can absorb moisture from the air over time. As moisture levels increase, the performance of the brake fluid can deteriorate, leading to reduced effectiveness in braking. Excess moisture can also lower the fluid's boiling point, which is significant because brake fluid needs to withstand high temperatures generated during braking without vaporizing. If the boiling point is too low due to moisture contamination, it can lead to brake fade, where the brakes become less effective under heavy use.

By measuring both moisture content and the fluid's boiling point, a brake fluid tester can provide valuable insights into whether the brake fluid is still safe and effective for use. Maintaining the appropriate levels of moisture and boiling point is crucial for ensuring the safety and reliability of a vehicle's braking system.