I might have an idea? I just ran into a similar problem. The clutch started acting like it was worn on my 90 Toyota pickup, so I replaced it. It didn't look bad, a little worn but still very useable, the throw out bearing and the pilot bearing were a little dry, so I was glad for the replacement. It acted the same after the install, so I replaced the slave cylinder. Still the same problem, the clutch wouldn't release until I was pushing the pedal into the carpet padding. I replaced the master cylinder, same problem. At this point, I'm pulling my hair out, what little I have. I must have run three quarts of brake fluid through that little bleeder trying to get the clutch to work better. Finally I got under the dash and looked around. There was a 2 inch crack in the pedal hanger bracket, up in the left hand corner. I grabbed hold of the pedal to see where the flex that would cause the crack was happening, and saw that the bolt that goes straight up, above the clutch pedal was moving. It was still bolted in tight, but it was moving. That bolt goes into a little bridge bracket that is tack welded to the under side of the wiper transmission tray. If you remove your cowl screen and look down inside the left hand (drivers side) access hole, just below the left wiper pivot, you will probably see a tear in the metal where that bracket is/was tack welded on. I came up with a down and dirty fix, rather than pulling the dash apart to weld that back together, and my clutch problems have gone away.
