Originally Posted by
onehundred80
It is possible that fluid is leaking by the piston seal it will not necessarily leak out, it just gets behind the seal and gets made up when the piston returns to its original position and oil passes through the seal gap. The seal may do this off and on depending on the seal damage. Crap getting under the seal would do this. I'd guess you need a new cylinder assembly.
I assume there's not a good test to see if it's the master cylinder piston vs the slave cylinder at the clutch.
The only symptom that leads me to the slave cylinder is the fluid I found inside the dust cover when I went to bleed the clutch hydraulics. I didn't find any fluid at the master cylinder when I pulled the dash.