How to Test the Water Content in Brake Fluid?
2 Answers
You can use a brake fluid test pen to check. More relevant information is as follows: 1. Brake fluid test pens are divided into conductivity test type and boiling point test type. The conductivity test type evaluates the quality of brake fluid by detecting its water content. 2. The specific working principle is to test the conductivity of the brake fluid. The test results are displayed through the built-in light-emitting diode (indicator light) of the testing instrument. 3. The standard is: water content below 0.5% indicates normal brake fluid; water content between 0.5% and 2.5%, the brake fluid can be replaced or not; water content above 2.5%, the brake fluid must be replaced. However, the test pen has a built-in fixed initial value and cannot be calibrated. Different manufacturers' test pens have different built-in initial values. Different brands of brake fluid have different formulations. If the brake fluid contains a large amount of metal additives, the test may sometimes show a red light, resulting in errors. It is recommended to use the boiling point test type of brake fluid together during testing. This will greatly improve the accuracy of brake fluid measurement.
As a seasoned driver with twenty years of experience, let me share how to test the water content in brake fluid. A simple and practical tool is a brake fluid tester, which is commonly available at repair shops. Insert the probe into the brake fluid reservoir, press the test button, and the LED light will display different colors based on the water content: green indicates normal (less than 1%), yellow serves as a warning (1%-3%), and red means immediate replacement is needed (over 3%). When performing the test yourself, remember two key points: testing when the car is cold yields more accurate results, and always wipe the probe clean before inserting it. The brake fluid reservoir cap can also absorb moisture if left unopened for long periods, especially during the rainy season in southern regions, so it's advisable to test every six months.
