A very basic way of explaining clutch operation from the driver’s perspective is: You press your clutch pedal, select a gear, release the clutch pedal and accelerate smoothly.
The clutch allows the engine power to be applied gradually, enabling you to pull away smoothly from a standing start and it interrupts the power train to avoid grinding gears while in motion.
Engaging the clutch (releasing your foot from the pedal) allows the power from the engine to be transferred to the gearbox and to drive the wheels. Disengaging the clutch (putting your foot down on the pedal) breaks this chain by stopping the power transfer, thereby allowing the engine to keep running without power being sent to drive the wheels.
The flywheel is bolted to the crankshaft of the engine, it also works with the starter motor to turn the engine over when you turn the keys at start-up. The flywheel also provides balancing for the engine, helping to dampen the vibrations caused by the engine firing. For the purpose of the clutch, it provides a smooth machined friction surface that the
The clutch plate is a steel disc, covered in friction material that goes between he flywheel and the pressure plate. A hub sits in the centre of the clutch plate and when the clutch is engaged the disc is squeezed. This stops the power from the engine reaching the gearbox, allowing you to change gears.
The pressure plate is effectively a clamp, spring loaded, that is bolted to the flywheel. Its heavy release springs flex when the clutch is engaged as it and the throw out bearing move towards the flywheel – effectively lifting the clutch plate from the flywheel. As the clutch pedal is released the pressure plate releases the clutch plate and power to the transmission is restored.
HOW DO I SPOT THE WARNING SIGNS THAT MY CLUTCH IS IN NEED OF REPLACEMENT?
If you notice the gears grinding when you change gear, this is a bad sign and one of the more obvious ones. Also if you have to press the clutch pedal all the way to the floor or if the biting point is particularly high your clutch may also need attention.
If the clutch pedal moves easily, but the car will not go into gear then get it checked immediately. Equally if the clutch slips out of gear without fully engaging, get it checked out – it could be that the linkage is out of alignment or it could be a worn clutch plate. Your clutch should not generally make noise, if it does start making noise when you change gear this could be down to an overheated clutch – this is often called clutch chatter. The clutch overheats when it slips, this can be noticed most on incline starts, or it can be caused if oil
is getting to the clutch plate.
WHAT SHOULD I DO IF I HAVE ANY OF THESE SYMPTOMS?
If you notice any change in your clutch biting position, or the amount of work you have to do with the clutch pedal to change gear get your car checked right away.
A failing clutch, whether down to hydraulics, gear linkage or the plates themselves can cause your vehicle to breakdown while driving. As with most major motoring ailments, catching them early and addressing them will save you a lot of money not to mention a lot of time from saving the inconvenience of breaking down – which let’s face it, always happens when you need it to least!