Need help with manual transmission parts and reason not working

I have a 1998 Ford Explorer, Sport Edition, 4.0L 4x4, Manual Transmission.



We replaced the clutch about a year ago. Everything has worked well until about a month ago when the clutch began engaging very low. We replaced the clutch master and then the slave cylinder seemed to not work so we replaced it even though we had just replaced it a year ago with the clutch.



After replacing the slave cylinder the the clutch began to work again but was engaging very low to the floor again which was the problem to begin with. We replaced the clutch master again thinking the parts we received were possibly defective and now the clutch will not disengage at all again.



We have tried a couple combinations to bleed the system and have no air in the system and we are not loosing any fluid.



Please help!! Any thoughts would be greatly appreciated! Winter will come soon and I need my 4 x 4!!

Any unusual noise coming from the clutch? Is the bell-housing up tight against the engine block? The next suspect is the clutch arm, the part the throwout bearing is attached to…They can crack and bend… The slave cylinder is mounted inside the bellhousing, right? Is there any way to observe its operation or is the housing completely closed?

No unusual noise from the clutch, yes the bell-housing is tight against the engine block. The slave cylinder is mounted inside the transmission and there is a viewing window. It appears there is no movement by the slave cylinder which would mean that the slave cylinder is not working. This is a brand new part that has now been replaced twice within one year and there is something strange happening when we replace parts. Chain of events is outlined in the original post, it’s confusing!