What makes it go
Learn about the clutch system
Did you ever wonder how the clutch works? Let me explain it to you.
The components of the clutch consist of:
- Clutch disk
- Pressure plate
- Throw out bearing
- Clutch cable
- Master cylinder
- Slave cylinder
- Clutch pedal
The CLUTCH DISK is a metal disk covered on both sides by a fiber, usually asbestos. The center of the clutch disk has a spline gear that is in constant contact with the TRANSMISSION mainshaft.
The PRESSURE PLATE is a metal spring attached to the FLYWHEEL. It exerts pressure on the clutch disk whenever the CLUTCH PEDAL is released.
The flywheel is a heavy metal disk attached to the crankshaft of the engine. The flywheel is usually heavy to allow the smooth running of an engine. The heavier the flywheel, the more torque the engine produces from a stop. The lighter a flywheel, the faster the engine revs up.
The THROW OUT BEARING is a roller bearing that makes contact with the pressure plate through the CLUTCH LINKAGE when the clutch pedal is depressed, releasing the clutch disk to spin free.
There are two types of clutch activation mechanisms:
One consists of a CLUTCH CABLE attached between the clutch pedal and the clutch linkage on the transmission. When the pedal is depressed, the cable pulls the linkage, pushing the pressure plate with the throw out bearing, releasing the pressure on the clutch disk. Periodic clutch adjustment is necessary for long life.
The other type is HYDRAULIC. The pedal is attached to a MASTER CYLINDER that in turn is attached to a SLAVE CYLINDER. The master cylinder pressurizes brake fluid to the slave cylinder. The slave cylinder is attached to the transmission next to the clutch linkage. When the pedal is pushed down, the slave cylinder pushes the pressure plate with the throw out bearing, releasing the pressure on the clutch disk. This disengages the transmission allowing smooth shifts.
When driving, the clutch allows smooth starts from a stop. It also allows smooth shifting from one gear up or down to the next.
Clutches last between 50,000 and 100,000 miles, depending on the kind usually of driving you do. City driving usually wears out the clutch faster than freeway driving. Resting your left foot on the clutch pedal wears the clutch prematurely, also.