1996 Holden Jackaroo Clutch

While driving I noticed my clutch pedal going soft so pumped it 5-6 times until I felt pressure again but the clutch only worked 2-3 times more until it went soft again and has not worked since. The reservoir at the master cylinder was empty so filled it and just have to bleed it now, but I do not think that will solve the problem as the clutch was working perfectly and went soft too sudden for it to be a small leak somewhere. Are there seals that can break in the cylinders or would it be a larger problem inside the clutch?