I am having an odd problem with my brake master cylinder. I am loosing fluid, and it appears to be leaking out the top of the reservoir where the lid sits. I can tell, because when I run the car, the outside cylinder gets wet with fluid, starting from the top down. What could be causing this? I am hesitant to replace the MC because I don't know if maybe the vacuum booster is leaking and causing the fluid to leak out of the reservoir? The brakes work just fine. The MC had been replaced about 5 years ago, but the car hasn't been driving much since.