Easy to follow step by step guide on how an automotive clutch assemblies work, though appearances may vary per application, the operation is the same in most vehicles.

A pedal assembly is used to operate the clutch by way of a primary cylinder to supply hydraulic pressure to a secondary cylinder. (Note: A cable is used on some older vehicles.)

Clutch Pedal
A clutch assembly is located at the rear of the engine and is bolted to the flywheel, which is connected to the crankshaft. Visit - How an Engine Works

Typical Automotive Clutch Assembly
The pressure plate is used as the actuator which releases and engages the clutch disc by holding pressure on the disc and the flywheel.

Pressure Plate Removed
A clutch disc is designed to be sandwiched between the flywheel and the pressure plate, this disc is fitted over an input shaft of the transmission. (Note: When a vehicle stopped and in gear, engine running, clutch pedal depressed, the flywheel and pressure plate rotate at engine speed, while the clutch disc is stopped).

Clutch Disc
An engine flywheel is connected to the crankshaft, and is designed to support the pressure plate that is attached using bolts.

Engine Flywheel Removed
Together these components make up the clutch assembly.

Clutch Assembly Cutaway
A throw out bearing and secondary cylinder is located on a transmission bearing retainer and is used to push against the fingers of the pressure plate to release and engage the disc, an input shaft rides inside the disc spline which transfers engine power to the transmission.

Throw Out Bearing - Input Shaft
The secondary cylinder and throw out bearing rides against the pressure plate fingers as the pressure plate spins on the flywheel. (Note: Optional designs include a clutch fork which is used with an external secondary cylinder or cable.)

Secondary Clutch Cylinder
A pilot bearing is used to support the input shaft of the transmission.

Pilot Bearing
Helpful Information

When a throw out bearing starts to fail it can make a chirping noise that is audible when the clutch pedal is depressed or released. A flywheel is different than a flex plate, which do basically the same job, a flex plate is used in automatic transmission vehicles and is thinner and lighter in weight. Most front wheel drive vehicles do not use a pilot bearing.

Common Problems

  • Clutch slip occurs when the clutch disc has worn out and replacement is required.
  • Clutch chatter, this occurs when the pressure plate has failed by not producing the amount of pressure to hold the disc correctly.
Article first published