Inspect for a burned or a glazed facing caused by oil on the facing.

Correct the leak at its source and install a new clutch disc.

Inspect for worn splines on the input shaft.

Replace the worn input shaft.

Inspect for a warped pressure plate or a warped flywheel.

Replace the warped pressure plate or the warped flywheel.

Inspect for a burned or smeared resin on the flywheel or the pressure plate.

Sand off the burned or smeared resin if it is superficial. Replace any burned or heat-checked parts.

Hydraulic clutch actuator cylinder damaged or worn

Replace the release cylinder.