Spring is upon us and with it comes maintenance, especially for those of you in colder climates where your cars have been in hibernation for the last few months. Most Lotus/Ariel owners perform the required maintenance, but many overlook one very important service: the Brake Flush. This service is very important for modern vehicles with complicated ABS systems. The fluid sitting idle in the system likely holds moisture and contaminants and should be replenished. Why? The water will expand when it gets hot causing brake fade and poor feel/performance - especially on track.
You may be wondering how water/moisture enters the brake fluid. It's very simple: most automotive brake fluid with the exception of DOT 5 (which is a silicone based fluid) is hygroscopic. This means it has the tendency to attract and absorb moisture from the atmosphere.
So, how can you tell if your car needs a brake system flush? They make special test strips which can detect high levels of moisture present in the brake fluid, but I prefer the old-fashioned eyeball method, personally. Remove the brake master cylinder cap and visually inspect the condition of the fluid. Brake Fluid should be clear or with a slight yellowish-tint. Black or dark colored dirty fluid should be changed out. You can also test it with a refractometer or a fancy electronic tester.
My personal recommendation for street-driven cars a biennial flush (every 2 years) but if you are taking your car to the track frequently, adjust accordingly. Sector111 recommend at least once per year for a track oriented car. If you are racing, we suggest even more frequent flushes...we've been very happy with Motul RBF600.