When is a clutch slave cylinder not a clutch slave cylinder?

[XfireZ51]

I have the car up on jackstands getting ready for trip to BG in a few weeks. Changed trans fluid, changed spark plugs, looking at exhaust(see thread), and I thought I would pull clutch slave cylinder to do a look see on the plunger sealing. When I went to drain clutch fluid by opening bleeder valve, the barrel of the cylinder rotated. I was pretty sure that meant new slave cylinder. Ordered a DOM replacement from Advance Auto for $74 plus shipping. Hoping it gets here by Friday. In the meantime, =Jeff= took mine apart and although the plunger seal was on correctly, it was pretty loose in the housing and the ridges of the seal were non-existent. I may have found why my clutch engages near the bottom of the pedal stroke. Stay tuned.