I have a 2004 350z that I just finished swapping the motor on to a new one with 65k miles. Went to bleed the clutch and noticed it was dropping to the floor so naturally I replaced the slave cylinder but it still drops into the floor and won’t bleed any fluid from the bleeder screw, pumping it also doesn’t seem to change how easy it is to press in (barely push with one finger and instantly drops). Does anyone have any ideas of what to check for? The clutch and flywheel were both replaced with new aftermarket ones during the swap. (Master cylinder was not touched)

 

Found it! Just had to gravity bleed the system a bit and bleed it for about a half hour but clutch feels good now.