1995 Corolla 1.8 brake problems (master cylinder, booster, slave)

[danpass]

Hey everyone:

Over the past week there have three or four instances where, at a stoplight, the pedal will sink to the floor. Didn't think much of it.

On the way home today the brake pedal went right to the floor and with enough pressure locks up right front wheel but doesn't really do anything to actually stop the car. (5spd manual transmission)

Master cylinder reservoir shows full, the small one closer to the fender shows full [clutch cylinder?](both pretty dark). Clutch works fine.

So ... where do I start? Pads/Shoes or just break out the new master cylinder from the auto parts store?

Will change fluid (or should I simply start with that?)


thanks,
dan