I have recently been experiencing a strange symptom on my 2000 Legacy Brighton with 5 speed Manual.
After I have been driving for a while I notice that when I depress the clutch there is definite lack of pressure or tension on the clutch for about half the distance - then the pressure is "normal". I am able to shift to the next gear up or down. When I release the clutch the pressure is normal for about half the distance - the pressure decreases.
I have checked the fluid reservoir and it is between the max and fill marks.
I believe that with the hydraulic there is no adjustment. I have owned other cars with hydraulic clutches and never experienced this before.