What is a throwout bearing?

A throwout bearing, also known as a clutch release bearing or clutch throwout bearing, is located in the clutch system of a vehicle. It is a key component in manual transmission vehicles. Specifically, it is located between the clutch pressure plate and the transmission, and here are the details of its location:

Where does a throwout bearing go?

Where does a throwout bearing go in the clutch assembly: The throwout bearing is located behind the clutch pressure plate and is designed to compress the diaphragm spring (or membrane spring) when the clutch pedal is depressed. This action allows the clutch disc to separate from the flywheel and engine, allowing for smooth shifting.

ACCESSORIES WITH THE TRANSMISSION: The throwout bearing is usually mounted on the throwout fork (or release fork) of the transmission. This fork is a mechanical linkage that brings the throwout bearing into or out of contact with the diaphragm spring.

Housing and Lubrication: The throwout bearing is housed in the flywheel cover, which is part of the clutch assembly. It is usually lubricated with grease to minimise friction and wear.

Function: When you depress the clutch pedal, the throwout bearing is pushed forward by the clutch linkage or hydraulic cylinder. Its main job is to make contact with the centre of the pressure plate, which keeps the clutch disc tight against the flywheel.

Throwout bearing operation.

- Engagement (clutch pedal released) : When the clutch pedal is released, the throwout bearing retracts and the spring force of the pressure plate pushes the clutch disc against the flywheel, connecting the engine to the transmission.

- Disengage (clutch pedal depressed): When the clutch pedal is depressed, the throwout bearing is pushed forward against the finger (or lever) of the pressure plate, releasing pressure on the clutch disc, thus disconnecting the engine from the transmission and allowing the driver to shift gears without grinding.

Action when the clutch pedal is depressed

- Initiates the disengagement process: when the driver depresses the clutch pedal, it starts a chain reaction that makes the pressure disc no longer press firmly between the flywheel and the slave disc.

- Eliminates the gap: firstly, it overcomes the free travel of the clutch pedal, i.e. it eliminates the initial gap between the release bearing and the pressure plate.

- Pushing the release mechanism: subsequently, the bearing pushes the release lever or acts directly on the pressure disc, separating it from the driven disc, permitting the engine to rotate without driving the vehicle and creating the conditions for shifting gears.

- Reduces wear: when the clutch is not depressed, the release bearing maintains a clearance between the release bearing and the pressure plate to avoid unnecessary wear, which is dependent on the free travel setting of the clutch pedal.

The throwout bearing is a critical component for smooth gear shifting and clutch operation. If it fails or makes unusual noises, it usually needs to be replaced as it is a wear item and usually beyond repair. When a throwout bearing is replaced, it is usually done as part of a clutch job that includes replacing the clutch disc, pressure plate, and sometimes the flywheel, depending on the condition and design of the vehicle's clutch system.

In summary, the throwout bearing is a key component in the clutch system, located between the clutch pressure plate and the transmission. It is attached to the throwout fork of the transmission and housed in the flywheel cover. Proper lubrication and maintenance of the throwout bearing is necessary to ensure smooth clutch operation and prevent premature wear.