It is probably your slave cylinder or your master cylinder.Before I tore into it to replace the slave cylinder, I would do a through inspection of the master cylinder. If it turns out to be your master cylinder, it well be a heck of a lot cheaper and easier to fix then the slave cylinder. I would first inspect the rod that is connected to your clutch pedal and goes through the firewall into your master cylinder. It's possible that the seal on the end of the master cylinder has gone bad.createing the problem.