[radiod]

Losing pressure on the pedal means you're either losing pressure elsewhere in the system or it simply can't build the pressure. As stated already, check the obvious places for leaks, any connection points, etc. I've seen some clutch cylinders leak IN to the car where the pedal goes through before as well, so check there. If you can't find any leaks, make sure the system is bled because any air in the system will cause all sorts of weird stuff depending on where it's trapped, the fluid temp, etc.