When does the pressure plate assembly rotate in a hydraulic clutch system?

When does the pressure plate assembly rotate in a hydraulic clutch system?

• A. The pedal is pressed
• B. The vehicle is in gear
• C. The pedal is released
• D. The engine is off

Answer: (C)

In a hydraulic clutch, the pressure plate is bolted to the flywheel, so it rotates with the engine whenever the crankshaft is turning. The hydraulic release system uses a throw-out bearing to push on the diaphragm springs and disengage the clutch. When you release the pedal, the springs clamp the clutch disc back against the flywheel, and the pressure plate and flywheel rotate together to transmit engine power to the transmission. When the pedal is pressed, the throw-out action releases the pressure, separating the disc from the flywheel so torque is not transferred. If the engine is off, nothing is rotating, so rotation only occurs when the pedal is released and the engine is running.

In a hydraulic clutch, the pressure plate is bolted to the flywheel, so it rotates with the engine whenever the crankshaft is turning. The hydraulic release system uses a throw-out bearing to push on the diaphragm springs and disengage the clutch. When you release the pedal, the springs clamp the clutch disc back against the flywheel, and the pressure plate and flywheel rotate together to transmit engine power to the transmission. When the pedal is pressed, the throw-out action releases the pressure, separating the disc from the flywheel so torque is not transferred. If the engine is off, nothing is rotating, so rotation only occurs when the pedal is released and the engine is running.