The master cylinder is the heart of any hydraulic system, and the hardest to troubleshoot. A pedal that can be slowly pushed to the floor indicates the master cylinder is worn. Fluid dripping off either the brake or clutch pedal is a sure sign that the respective master cylinder is leaking. Only one (single line) brake master and one clutch master are currently available, but they will fit any year Mini. Brake and clutch masters look similar, both these later models have plastic reservoirs, and they are NOT interchangeable because they're different internally. See GMC171/ORIG for metal can.