So with some help from the board I successfully replaced the seals on the brake fluid reservoir, put the whole thing back together and went for a test drive. The pedal got a little soft then the brake failure light came home.

I removed the brake failure sensor, including the little piston and spring, cleaned it all up and put it back together. Didn't see any noticeable fluid where the sensor goes. Put it back in, brakes seem a lot better, no light on. The light does come on at ignition btw.

So what exactly has happened and should I be safe to drive? Originally, only one side of the reservoir had went empty, and I hope I have restored the balance between the brakes. I am not that familiar with all this and a little nervous, just looking for a logical explanation to what has happened. Thanks in advance.