Hydraulic clutch problems

I have a '97 Nissan Pathfinder with a hydraulic clutch. Six months ago, the clutch lost all resistance and would fall to the floor and not return. I had the master and slave cylinders replaced and that took care of the problem.

Well, the problem returned. I have to pump the clutch 20-30 times before it is able to be used. There is no fluid missing from the system, but the pedal has no resistance and does not return to the engaged position. The mechanic replaced the slave cylinder and this helped but did not fix the problem.

Reading related topics/discussions didn’t help me except it seems that if the system loses hydraulic fluid, the problem is the slave cylinder. If it doesn’t lose fluid, it is the master cylinder. Is this true? Is there any other possibilities? Thanks.

Generally that is true. If no fluid is missing from the system, then you do not have a leak. If you have to pump to get the pressure up enough to shift, then you have a master cylinder problem. There may be a tear in the piston or a score in the cylinder, and fluid is leaking past internally, killing the pressure.

These system is simple enough. Return it, and have it fixed properly.