What does a clutch do? Everything you need to know

Almost all mechanical devices are equipped with a clutch. You may be surprised to know that your manual transmission has more than one clutch. The same is true with automatic transmissions. Mechanical devices like kid yo-yos have a clutch, chain saws are equipped with a centrifugal clutch, and cordless drills have a clutch.

You might be asking ‘what does a clutch do’ or what is a clutch? This article has provided sufficient information regarding your questions. It’ll also outline causes of worn clutches you should watch out for and how to mitigate clutch problems. Sit back and have a 5minutes read.

What Is A Clutch, And How Does It Work?

what is the clutch in a car

In manual transmissions, the clutch is responsible for engaging and disengaging the driveshaft from the transmission. It requires the driver to take extra action by depressing the clutch pedal to shift to higher, lower, and reverse gears. The clutch is what makes the engaging and disengaging of gears possible.

Now, you might be wondering, ‘what is a clutch pedal?’ It is the third pedal on manual cars. It is the first pedal located on the driver’s seat floor next to the brake pedal. It takes command from the driver to the clutch system to engage or disengage the clutch, which disconnects power from the engine to the transmission when depressed.

The clutch consists of the flywheel, clutch disc, throwout bearing, and driven plate. The clutch disc is designed with diaphragm springs.

The clutch disc is mounted on the flywheel at the rear end of the crankshaft between the engine and transmission. The pressure plate exerts pressure or applies pressure on the driven plates. The process of exerting or applying pressure is accomplished by coil springs on older vehicles, which on newer cars, is achieved by diaphragm springs.

The diaphragm springs are designed to run on a splined shaft. It is found between the pressure plate and the flywheel. The work of a throwout bearing is to unhitch the spring load either by a hydraulic or cable control to disengage the engine from the transmission.

Now that we’ve outlined the components of a clutch system and their functions, in general, how does a clutch work?

Whenever you step on the clutch pedal, the system pushes the release fork through a cable or hydraulic piston from the down clutch kit. The clutch fork then pushes the clutch moon (also known as release bearing) against the clutch pressure plate.

Several diaphragm springs pull the clutch disc as the pressure plate moves backward from the drive plate and eliminate the friction between the flywheel and the driven plate. This leads to disruption of rational power transmitted from the engine to the transmission via the help of a flywheel.

Once the transmission is disconnected from the engine, you can easily and smoothly shift gears to different gear ranges.

When the clutch is fully engaged, and you release the clutch pedal, the pressure plate releases rational force on the driven plate. Since the pressure plate is directly mounted on the flywheel, which on the other hand, is mounted on the rear end of the crankshaft, the driven plate rotates under it to transfer the rational power to the transmission.

What Are The Signs Of A Worn Clutch?

clutch problems and solutions

Several symptoms will pop up to notify the driver of a car clutch problem. Let’s look at the detailed list of symptoms of a worn clutch.

Soft clutch pedal: Clutch pedal requires a certain degree of force on your foot to depress it regardless of the manual transmission model you own.

If the clutch pedal becomes incredibly soft when depressed, it indicates an issue with the clutch system. This issue can arise from low clutch fluid, up or down clutch kit failure, or a problem from the pressure plate. Whenever the clutch pedal becomes soft than usual, you may need to diagnose the clutch assembly to figure out the cause of the problem.

Hard gear shifting: A well-functioning clutch and transmission will smoothly shift into higher and lower gears. Since the primary function of a clutch is to release the rational force that is transmitted from the engine to the transmission, so you can shaft to different gear ranges. If the clutch fails to perform this function, you will experience hard gear shifting.

This happens to all transmissions when the clutch goes bad. So, if your gear has become extremely difficult to shift to different gear ranges lately, you need to inspect the clutch.

Stiff clutch pedal: A stiff clutch pedal indicates a problem with the pressure plate. It can also mean issues with the clutch hydraulic system, like a defective clutch master cylinder. Hence, it is advisable to diagnose your vehicle before jumping to conclusions.

Noise when depressing the clutch pedal: If you hear a strange noise when depressing the clutch pedal or changing gears, it is likely a sign of a bad throwout bearing, drive plate, or pressure plate.

The throwout bearing is responsible for pushing the pressure plate to engage and disengage the clutch. Like every other clutch component, this bearing can fail and cause issues. It is usually replaced with a clutch. Whenever your car starts emitting strange noise when depressing the clutch pedal or changing gears, contact your mechanic or dealership to track down the culprit and fix it ASAP.

Slipping clutch: If you experience clutch slipping when accelerating the car, diagnose the clutch system. A bad or failing clutch typically slips, especially when carrying a heavy load or climbing hills. In such situations, there’s a likelihood that some drivers will keep depressing the accelerator pedal to gain traction, this will only cause the engine speed to increase, but the vehicle won’t move as fast as it should.

Clutch slippage causes overheating to its components and leads to accelerated component wear and damages. In a worst-case scenario, a damaged clutch can prevent the vehicle from moving forward or backward. This, however, won’t happen suddenly. Before it gets to this state, it’ll display some signs to notify the driver of a problem in the system.

Higher clutch pedal: Usually, when the clutch pedal starts wearing out, the pedal will come up more than its standard height. On older vehicles that use clutch cables and rods, it will require a mechanic to adjust it whenever it goes high.

In contrast, new cars use a hydraulic clutch system. The hydraulic system automatically makes this adjustment. Therefore, you don’t have to contact your mechanic to perform any adjustment tasks.

Unfortunately, if the hydraulic system wears out to the extent the hydraulic system can’t adjust it anymore (which happens earlier than the manual adjustment), the clutch will require replacement.

Clutch pedal goes to the floor: Amidst other symptoms, the clutch pedal can stay on the floor as a sign of a defective clutch. This is usually caused by a bad throwout bearing, clutch pressure plates, or hydraulic systems.

Whenever this comes upon a vehicle, the first diagnosis should be on the hydraulic system before heading to the clutch.

Having discussed the symptoms and causes of clutch failures, let’s look at the frequently asked questions that you might be wondering about.

FAQs

Q: When should I press the clutch while driving?

This is a vague question. However, it all depends on the speed you’re traveling at and whether you’re driving downhill or uphill. These are when you need to depress your clutch;

  • When changing to different gear ranges
  • When slowing down
  • When braking on low gears
  • When shifting to 1st gear

Q: Can you drive a car without a clutch?

As explained earlier, the clutch engages and disengages the engine’s rational force from the transmission. Driving with defective and no clutch on a manual transmission can be tricky and lead to catastrophic damage to the transmission. However, you can run without a clutch in an emergency and for a short period.

Q: Is it bad to press the clutch?

The driver can smoothly engage and disengage the transmission by depressing the clutch pedal. This means pressing the clutch is not bad.

However, some habits or situations make pressing the clutch bad. The following are driving habits that can cause severe damages to your transmissions;

  • Depressing the clutch at a spotlight
  • Changing gears slowly. That is lingering when stepped on the clutch pedal
  • Depressing the clutch pedal while accelerating the engine to 4,000 to 5,000 RPM
  • Riding the clutch. This means partially stepping on the clutch while driving

Ensure you step only when shifting to different gear ranges. Do not ride the clutch while driving. Depressing the clutch pedal when you’re not supposed to, even for the shortest time, will cause accelerated component wear.

Q: Are clutches expensive to replace?

Several factors affect clutch replacement cost. These factors include vehicle make and models, whether it is a hydraulic clutch or not, the mechanic handling the job, your location, and whether it is a manual or automatic transmission.

In any case, the average amount of clutch replacement is between $1,100 to $1,200. The parts should be between $600 to $650, while the service fee estimation is $500 to $550. However, your location can cut down the cost to $750.

In some cars, you have to pay around $350 for the replacement parts. The replacement cost will be reduced if the mechanic will not change all the clutch components.

Q: What happens if you change gears with a clutch?

Changing gears without depressing the clutch will emanate car clutch problems. If you form this as a habit or you do it for a long time, it will cause catastrophic damages to your transmission.

Q: Can a clutch fail suddenly?

A clutch can fail either suddenly or gradually. Sudden clutch failures are usually caused by the failed hydraulic master cylinder, loose, bent, or broken clutch cables/rods. There might be a sudden fluid leak in the hydraulic system, or the disc surface may have accumulated dirt and debris.

Q: Should I press the clutch while turning?

Shift to lower gears and maintain that range throughout the turning. Always shift to lower gears when making a turn instead of depressing the clutch pedal. Aside from using engine braking, shifting to lower gears before making turns keeps you at a required RPM which guarantees a smooth return to high speed after the turning.

Q: How long should a clutch last?

It all depends on your driving habits and styles. Most clutches can travel over 60,000 miles before needing replacement, while some can last only 40,000 miles.  Others might wear off before 30,000 miles, which is abnormal.

If you use your baby ride for inter-state travel or cruising on the highways, the clutch will last much longer than another driver who’s doing city stop-and-go driving.

Final word

Having answered the question ‘what does a clutch do’ and explained clutch problems and solutions, and the signs of a bad, you have to watch out for the outlined clutch symptoms above and fix any problem before it causes damage to your transmission.

Regardless of how useful the clutch application is, only apply it when necessary.  Do not ride on the clutch for any reason except when driving on 1st gear.

If you want your clutch to meet or even exceed your lifespan expectation, follow our driving habits tips to and prevent premature component wears.

Osuagwu Solomon

Osuagwu Solomon is a seasoned automotive technician for the past 9 years, and a technical writer. He loves writing about auto professional repair guides, DIY repair guides, and buyer’s guide. After spending six years in the automotive workshop, he decided to impact his knowledge to people aside his domain, and he has achieved this by centering his Automotive writing skills on REPAIRS.

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