clutch down near floor

1995 2.6litre 4WD Dual cab. The clutch still works but is down near the floor. The clutch actuating lever is only moving a small amount about 1/4 when the clutch is depressed. There is a lot of travel left in the lever. I have bled the system and changed the fluid. I was told this problem may be due to a return spring in the Master cylinder not moving the piston all the way back. Any suggestions greatly appreciated.
Chris :banghead: