To fix hydraulic clutches, first identify the exact problem, such as the clutch pedal traveling to the floor with little or no resistance, the pedal feeling soft when depressed and the clutch slipping. There also may be noises coming from the area around the clutch.
If you are using very little force when pushing the clutch pedal, check the clutch master cylinder and the clutch slave cylinder for leakage. Replace any leaking cylinder. Next, check whether the hose from the brake fluid reservoir to the clutch master cylinder is leaking. Also, check for leakage in the fittings at the clutch master cylinder and the line to the clutch slave cylinder.
If there is a soft feel to the clutch pedal when you depress it, there is air in the system. Check the brake fluid level and refill if necessary. If the clutch slips, the clutch disk may be worn out or contaminated. If the disk is in proper condition, disassemble clutch and the check if the flywheel or the pressure plate is warped.
If there are noises coming from the clutch area, check whether the release bearing or the pilot bearing is damaged. If the bearings are in good condition, check whether there is a broken spring in the pressure plate. The noise may also be as a result of a broken spring in the clutch disk.