If you’ve ever seen a clutch assembly drawing, you’ll notice that your vehicle’s clutch assembly has many different parts. Each of these vital parts has a role to play whenever you engage the clutch to shift gears. Today, we’ll take a look at the clutch assembly’s different parts and what each part does when it’s time for you to shift gears.
Automotive Clutch Assembly Parts
Your vehicle’s clutch assembly is a link that connects the engine and the transmission. It’s connected to two rotating shafts. The input shaft connects to the engine. The output shaft attaches to the rest of the transmission system and is driven by the engine to provide torque to the vehicle’s wheels. The vehicle’s clutch allows you to interrupt torque transmission while shifting gears.
Your vehicle’s clutch is always either engaged, slipping or disengaged. When the clutch is engaged, the shafts rotate at the same speed and are locked together. When the clutch is slipping, the shafts are moving at different speeds while locked together. A disengaged clutch has the shafts rotating at different speeds and not locked together.
These three clutch states are possible thanks to these key parts:
Pilot Bushing or Bearing
The pilot bushing or bearing allows the transmission’s input shaft and the engine’s crankshaft to rotate at different speeds when the clutch is disengaged. This part is located in the center of either the flywheel or the crankshaft flange, and it can be either a bearing or a bushing. Pilot bearings are ball, needle, or roller bearings packed in grease, while pilot bushings are lubrication-infused brass.
Flywheel
The clutch assembly’s flywheel permanently attaches to the engine’s crankshaft, and it rotates when the engine crankshaft rotates. Its movement depends entirely on the engine. Almost all other parts in the clutch assembly rotate at the flywheel’s speed. The only exception is the clutch disc and the transmission input shaft, which serves as the clutch’s output shaft. The flywheel’s teeth, which run along its edge, interact with a small, round gear called a pinion when the vehicle starts. The starter motor uses the flywheel to kickstart the engine using battery power before the engine starts powering itself using fuel.
Clutch Disc
The clutch engages or disengages by applying pressure to the clutch disc, which connects to the transmission input shaft. The clutch disc sits between the flywheel and the pressure plate. When the clutch is engaged and your foot is off the clutch pedal, the pressure plate holds the clutch disc against the flywheel, causing the clutch disc to rotate at the same speed as the flywheel and the engine. When you press your vehicle’s clutch pedal, the clutch disengages by pulling the pressure plate away from the clutch disc.
Pressure Plate
As we’ve mentioned, the pressure plate rotates at the same speed as the flywheel and the engine crankshaft. It sits bolted onto the flywheel and clamps the clutch disc down when the clutch is engaged. The pressure plate has a diaphragm spring at its center that releases the pressure on the clutch disc whenever you press the clutch pedal to disengage the clutch.
Release or Throwout Bearing
The clutch release or throwout bearing pushes against the pressure plate’s center diaphragm spring when you press the clutch pedal. This pressure forces the pressure plate away from the clutch disc, which in turn disengages the clutch.
How To Measure Clutch Assembly Replacements
If you’re looking to purchase a clutch disc replacement or other clutch assembly parts, it’s best to double-check that they fit your vehicle’s exact year, make, and model. You can also take the measurements yourself, just to make sure that you’re getting correctly sized parts.
To start, you can measure the clutch disc diameter by measuring across the clutch disc’s face. Take the pressure plate’s diameter by measuring from its backside. Finally, measure the clutch’s bolt pattern by measuring the distance between its bolt holes.
These measurements are helpful for double-checking the proper parts sizes and for working on older vehicles that might not have readily available and labeled parts. Now that you know the basics behind the clutch assembly parts and their functions, you’re better prepared to deal with any clutch assembly issues that might crop up.
Keep Reading: Related Posts
Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.
