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What is wrong with my car's clutch?
Brought to you courtesy of Tramcar Transmissions
Clutch Basics 101
1) What is a clutch? A clutch is a coupling between the engine and the transmission, which allows the driver to gradually transfer the power from the engine to the transmission. In addition, the use of a clutch allows you to leave the transmission in gear and bring the vehicle to a stop. If the clutch was not disengaged the engine would die when the driver brought the vehicle to a stop.
2) How does a clutch work? A disc normally referred to as a clutch disc is sandwiched between a spring-loaded plate called a pressure plate and a flywheel. The disc has spines in the center that link to the input shaft of the transmission. When the engine is started, the flywheel and pressure plate rotate in relation to the rpms of the engine. When the clutch is engaged, it is driven by both the flywheel and the pressure plate and revolves at the same speed as the two driving components. It in turn drives the input shaft of the transmission, which ultimately turns the drive shaft or axle to propel the car. When the clutch pedal is depressed (clutch disengaged) the pressure plate retracts away from the disc no longer driving the clutch disc. Although the engine is running and the flywheel and pressure plate spinning, the disc is no longer sandwiched between the two and no longer rotates, which allow you to shift gears or bring the vehicle to a stop.
3) What happens when the clutch slips? This is the major complaint of a faulty clutch. When a clutch slips the clutch disc no longer revolves at the same speed as the flywheel and pressure plate and as a result cannot turn the input shaft of the transmission as fast as the engine. The problem is most often associated with a worn out or burned clutch disc. The disc has a fibrous material bonded to it's surface, this material is similar to the lining on brakes. As this material wears down or begins to burn, it no longer as the ability to "bite" and hold firm between the flywheel and pressure plate. When that happens the clutch will slip which is where the term, "Clutch Slipping" originated.
Major parts of a clutch system
Flywheel - This component is used to start the engine and drive the clutch disc. When a clutch disc slips it usually damages the mating surface of the flywheel.
Pilot bearing - Pilot bearing - supports the input shaft of the transmission and is pressed into the rear of the crankshaft of the engine.
Clutch disc - The driving force of the input shaft of the trans. This component is the item that actually slips when the engine races but the vehicle doesn't move.
Pressure Plate - The clamping force of the clutch, and the mechanism to release the clutch disc. When a pressure plate doesn't release it makes it extremely difficult to shift gears.
Throw-out or release bearing -The bearing that applies pressure to the fingers or springs of the pressure plate to release the disc. The bearing retainer will support most bearings.
Bearing retainer -This component supports the throw out bearing and retains the front bearing of the transmission. The inner portion of the retainer usually has a seal that seals the input shaft of the transmission.
Clutch Fork - The fork operates the throw out bearing and is actuated hydraulically or mechanically. The fork will have an inside or outside pivot that must be inspected when servicing.
Clutch Cable - The cable is fastened to the clutch pedal and the other end to the clutch fork. This is a mechanical connection to the fork. The cable should operate smoothly with no binding or hard spots.
Hydraulic Master Cylinder - This is normally bolted to the firewall of the engine compartment and connected to the clutch pedal via a push rod. This component forces fluid down to a slave cylinder when the clutch pedal is pushed.
Hydraulic Slave Cylinder - Normally mounted to the bell housing of transmission when externally mounted and engages the clutch fork. When internally mounted it actuates the throw out bearing directly
Clutch Pedal with Linkage - This is the actual clutch pedal along with the pivot linkage required to smoothly operate the pedal. The pedal controls the releasing of the clutch assembly. Always check the pedal bore for uneven wear as this can cause the pedal to bind when applied.
Now that we have an understanding of the basic components we can answer the question at the top.
1) What do I need when I need a clutch? We have listed 11 major components of a clutch system. In order for a clutch to operate efficiently it requires these components to work as designed. Very seldom would all of these parts need to be replaced, but many times a combination of these parts is required to properly repair the clutch system. I do emphasize the word "system" because a clutch is a system and not one single item. So that is why a reputable repair shop will not be able to give you an accurate quote to repair your clutch until they know what components are required. And that certainly cannot be accomplished over the phone.
2) How do I know if I need a clutch? This more than likely is not a question that you can answer yourself, unless you're a qualified automotive technician. But some of the more common symptoms that suggest a clutch related problem would be; 1) The engine races (slips) when the transmission is in gear 2) The transmission makes a grinding noise when trying to select a gear, especially reverse 3) A noise when you depress the clutch pedal which goes away after you release the clutch pedal 4) The vehicle feels like it chatters as you release the clutch pedal. These symptoms all indicate that you have some type of clutch related problem, not necessarily a major problem, but a symptom that should be evaluated by a professional.
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I hope you have found this article informative and you received the information that you were looking for. If you still have questions or would like to get you vehicle checked out by a professional. Please Give Us A Call at (773) 792-1003.
Or email us with any questions Tramcar@sbcglobal.net