OK, so I've heard mention several times of a "known clutch slave problem" which seems to appear on a number of different models across the board in at least the late '90s and early '00s. In fact, when I had my '01 996 in for it's 6000 mile service, the shop noted that my slave cylinder had never been warrantied or serviced, so they simply replaced it for free under some technical service bulletin even though I had experienced no problems of which I was aware. This weekend I was working on a buddy's 1999 Monster 750 who is having clutch issues for a second or third time. The clutch lines clearly are getting air into them somehow. Even after running an entire bottle of DOT 4 through it, I still can't get it entirely free from air bubbles (and yes, I'm successfully bleeding it without introducing any more air from either end). While actuation is back to functional after my servicing, it bothers me that I can't get it completely bled. Plus, it obviously has an underlying cause that hasn't been addressed simply by bleeding since it comes back after a while. So, my question is, what are the symptoms of a "typical bad clutch slave"? What is this known problem? My buddy is not the kind to spend money on upgrades (although there are obviously many aftermarket clutch slave options specifically because so many had problems), so what are the odds and would it be worth trying to get the dealer to replace his under whatever TSB/Warranty they did mine under? Any other components sound like they might be the culprit? Gracias, amigos.