Ok, last week my brakes started feeling a little light, then the light came on and the pedal went pretty much freely to the floor. Scared the crap out of me. I then filled it, pumped them up and the light went off and they worked fine. Today, it happened again. Was able to put a bunch of fluid in again today and breaks were weak. I looked everywhere for a leak and we couldn't find one. I'm thinking I should look at the rear brake cylinders. What are your thoughts and experiences?