On Brake Fluid rating, what is meant by dry and wet boiling point? >And why would you know which one pertains to your application >at any given time?
Terry, Brake fluid is hydroscopic (absorbs water). When fresh from the can, it can be considered “dry” with the higher boiling point. That’s why racers and people doing driver’s schools change the brake fluid just before events. Over time, brake fluid absorbs water lowering its boiling point to the “wet” level. For street cars, wet boiling point numbers are more important than dry because the fluid stays in for quite a while (one to two years). After a few months, with exposure to humid air, the brake fluid performance is probably closer to the wet than dry point. … Brake fluid needs to be changed for two reasons, maintenance and performance (it takes about a quart to flush the system). Maintenance – changing old brake fluid removes water from the brake system. Brake fluid is hydroscopic, it absorbs water. Old brake fluid must be flushed out or water absorbed by the fluid eventually causes internal rust on the disk calipers and pistons. Performance – changing old brake fluid helps hi
