Check for a stuck concentric slave cylinder.

Replace the concentric slave cylinder. Refer to Clutch Concentric Actuator Cylinder Replacement .

Check for improper return of clutch oil.

Perform the air bleeding. Refer to Hydraulic Clutch Bleeding .

Check for a worn clutch disc or oil contamination.

Replace the necessary clutch components. Refer to Clutch Assembly Replacement .

Check for a warped pressure plate.

Replace the necessary clutch components.