Aveley Garage & M.O.T. Centre

All About the Clutch: What Is It?

Raise your hand if you’ve ever driven a manual shift car. You’re probably familiar with the clutch by now. This third pedal that you have to press in order to change gears is essential to ensure road safety.


But if you’ve only driven cars with automatic transmissions, this car part may not be familiar to you. While you’re on the road, your car’s engine is always spinning. There has to be a way for the wheels to disengage for them to stop moving.


The clutch makes this possible – it disengages the wheels without killing the engine, acting almost as a brake. To learn more about this essential car part, continue reading this blog.


What Does It Do?

This mechanism functions by engaging and disengaging the car’s power transmission from the driving shaft to the driven shaft. It also connects the rotating shafts (there can be two or more under the car’s hood). For cars with a manual transmission, it is connected to both the shaft that turns the wheels and the shaft coming from the engine.


You don’t want the wheels continually spinning, even while the engine is going to spin constantly. One of the rotating shafts is the driving member, which is connected to the engine or power unit. The other shaft is called the driven member; it provides output for work.


The clutch connects both the driving and driven member so they can be engaged or disengaged, spinning at the same speed or at different speeds. These motions are rotary, but linear ones are possible.


How Does It Work?

At this point, you must be wondering what happens when the clutch pedal is pressed. A hydraulic piston or cable pushes on the release fork, in turn pressing the release bearing. This disengages the engine from the transmission against the middle of the diaphragm spring during gear shifts.


A series of pins near the outside of the spring gets to work while the middle of the diaphragm spring is being pushed in. This causes the spring to pull the pressure plate away from the clutch disc. The clutch is then released from the spinning engine.


The springs in the clutch plate help to isolate the transmission from the shock of the biteing point, which refers to the point when the clutch becomes engaged. This mechanism works well, but it has a few drawbacks. We’ll look at these problems later. Let’s first have a look at how the clutch is designed.


Clutch Design

It’s been designed so that the connection between the wheels and the motor can be broken in order for the car to come to a stop without the entire engine shut off. The clutch is made up of two main parts: a clutch plate and the flywheel.


As mentioned, there are springs in place. They are responsible for keeping pressure on a plate that pushes up against the clutch plate and also for pushing the clutch plate up against the flywheel. Car clutches come in different types, such as:

  • Centrifugal clutches;
  • Cone clutches;
  • Friction clutches;
  • Multiple plate clutches; and
  • Wet versus dry systems.


Most clutches rely on frictional forces to operate. They connect one moving member to another one that is moving at a different speed (or not at all) to get it moving at the same speed. That way, there is no slippage.


These clutches are made with certain materials that help create friction. These include ceramic, compound organic resin, copper wire, and composite paper. Ceramic materials are mostly used in racing or heavy-duty hauling situations, but they can increase wear and tear on the pressure plate and flywheel.


Common Clutch Problems

Car clutches from the 1950s to the 1970s could last between 80,467 and 113,000 kilometres. Now, you could count on getting 128,747 kilometres from your car’s clutch if you use it gently and maintain it well. Most clutches can start to break down at 56,000 kilometres if not cared for.


The friction material on their disc wears out. This material is similar to the material on the shoes of a drum brake or the pads of a disc brake. After a while, it wears away, and the clutch will start to slip, unable to transmit any power from the engine to the wheels.


Apart from the friction material wearing out and the clutch slipping, another common problem is sticking. The clutch will continue to turn the input shaft if it won’t release properly. This can either cause grinding or prevent the car from going into gear.


For Clutch Repairs and Replacements

Do you suspect your car’s clutch slipping or sticking? Turn to Aveley Garage and MOT Centre for clutch repairs and replacements! When you hand your car over to us, our experienced mechanics will inspect every essential car part, especially the drivetrain. Let our team repair this important part of your car so you can stay safe on the road.


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