Abstract
In case that a motor vehicle accident was caused by vapor lock of brake fluid, its boiling point should be measured. However the brake fluid collected from the car is in an extremely small quantity, it is not possible to measure the equilibrium reflux boiling point (ERBP) as defined by the Japanese Industrial Standard. Consequently it becomes difficult to investigate the cause of the accident. Measuring the boiling point of small amount of the brake fluid, the measurements of relative dielectric constant (RDC) is used. Because the boiling point of the brake fluid chiefly made up of glycol ether falls sharply by absorbing moisture, the measurements of water content by RDC is applied. Results are as follows: ERBP can be measuredeven when the collected brake fluid is about 1/10 of the quantity needed in the traditional method. Accuracy of this method is more precise.
