(1) Rule out slippage when combining. Readjust the pedal's free travel; Replace the pressure spring; Clean the oil on the surface of the clutch friction plate; Replace the friction plate. 

(2) To eliminate the vibration failure when combining. Replace clutch shaft or sleeve; Tighten the loose bolts; Clean the grease on the friction plate; Readjust the clutch separation lever to a uniform state. 

(3) Remove the phenomenon of incomplete clutch separation. Re-adjust the free travel of pedal too large; Readjust the clutch release lever.