How often should the clutch plate be replaced? In fact, there's no fixed replacement time for clutch plates. As long as the wear is within the allowable range, there's no need to replace them.
If the vehicle starts slipping, can start in low gears but experiences stalling and engine lag in high gears where increasing the engine speed doesn't increase the vehicle speed, or can be started in high gears by pulling the handbrake, stepping on the clutch pedal, and slowly releasing the clutch pedal, and the engine stalls, then the clutch plate does not need to be replaced. If the engine speed hardly changes after releasing the clutch pedal, it means the clutch plates are excessively worn and need to be replaced.
Once we understand the principle of the clutch, we'll have a more intuitive understanding of the lifespan of the clutch plates, knowing why and how. Let's take a look at the physical components of the clutch: flywheel (driving plate), friction plate (clutch plate), and pressure plate, which are the main components of the clutch plate car.
The flywheel is connected to the engine crankshaft and is also responsible for storing energy and starting the engine. It can be understood as the output part of the engine power. The clutch plates are between the flywheel and the pressure plate. Behind the clutch plates is the pressure plate. The pressure plate is fixed to the flywheel with a row of screws and rotates at the same speed as the flywheel. The pressure plate has a pre-tightening spring which presses the clutch plates on the flywheel. The frictional force causes the clutch plates and the flywheel to rotate at the same speed. In the middle of the clutch plate, there's a spline bore. The gearbox's input shaft is inserted into the spline bore of the clutch plate, and the gearbox's power is provided by the clutch plates.
When the clutch pedal is fully depressed, the release bearing pushes the release lever, which applies pressure to the pressure plate. The pressure plate overcomes the pressure of the spring and rebounds. At this time, the pressure on the clutch plate disappears, and the frictional force between the clutch plate and the flywheel is reduced. Therefore, the clutch plate stops rotating, and the power of the engine cannot be transmitted to the gearbox. When the clutch pedal is partially depressed, the pressure plate doesn't fully rebound, and the pressure on the clutch plate naturally decreases. The frictional force between the clutch plate and the flywheel decreases, and the clutch plate will slip. The engine power can only be transmitted to a part of the clutch plate because of the slip, the rotational speed of the clutch plate decreases, which creates a semi-detached state during start-up. In other words, the clutch plates and the flywheel generate friction to reduce the input speed of the gearbox, controlling the startup speed to prevent engine stalling.
The clutch plates are also called friction plates because the transmission of power through the clutch plates in the working process is achieved by friction. Scrapped clutch plates not only cause the disappearance of the friction materials but also wear out the rivets, leaving only a piece of sheet metal. Without friction materials, the frictional force naturally decreases, and the clutch plates may slip, making it impossible to transmit power to the gearbox, leading to an inability to drive, which is one of the signs of severe wear.
Often wear will result in higher repair costs because the clutch plate becomes sheet metal, causing wear on the pressure plate and flywheel that come into direct contact. Therefore, when signs of slipping clutch plates are observed, it's necessary to replace the clutch plates promptly to avoid increasing cost.
In addition, it's essential to develop reasonable driving habits in everyday driving, and try not to adjust speed by constantly combining the clutch and separation (except for cycling). When the vehicle is stuck in a trap, timely rescue is needed instead of freeing it by stepping on the gas pedal with a semi-detached clutch. High-speed rotation can quickly damage the clutch plate. Of course, when lifting the gearbox, check the three-piece clutch assembly. If the clutch plates are worn, replace them promptly to avoid future problems.