Is a 2 yearly brake fluid change still necessary?
In these days of advancing technology, is it still necessary to change brake fluid every 2 years. I recall in the 1960's that the brake fluid was hydroscopic (absorbed water) and it would boil at a lower temperature and hence the 2 year change interval. Is that still true in today's world of high technology and synthetic fluids?
While the two-year brake fluid replacement guideline remains the recommended interval, a test of the brake fluid quality is a more reliable indicator of its condition and whether it is in need of replacement. The majority of modern brake fluid types remain hydroscopic, and so their performance can be affected by the absorption of water, both in terms of the braking performance and also the effects of corrosion on braking components. DOT 5 fluid is hydrophobic due to its silicone make-up and therefore avoids issues with water absorption, but due to its composition it is not compatible with ABS systems. While the composition of more conventional brake fluids has been subtly refined over the years, it is designed to be compatible with a wide range of vehicles and like most vehicle fluids it is good practice to check and replace them where appropriate.
Answered by David Ross on
