Clutch release bearing

 I. Definition and function of clutch release bearing

Clutch release bearing, also known as clutch release bearing or clutch thrust bearing, is an important part of automobile clutch system, mainly located in the clutch housing or flywheel housing. Its main role is to support the clutch disc, reduce the friction between the wear and ensure the normal operation of the clutch.

1. To achieve clutch disengagement:

   - When the driver depresses the clutch pedal, the release bearing is pushed forward through a series of mechanical connections (e.g., the release fork), and this action compresses the release lever so that the pressure between the pressure plate and the flywheel is reduced, permitting the clutch disc to separate from the flywheel. This process allows the engine to be temporarily disconnected from the driveline, providing conditions for shifting gears or starting.

2. Maintaining smooth engagement and disengagement:

   - The release bearing ensures a smooth transition between engagement and disengagement of the clutch, avoiding the shock and damage that can be caused by a hard connection and ensuring smooth gear changes.

3. Reduced wear:

   - When the clutch is not operated, the release bearing maintains a certain clearance from the release lever by means of a return spring, reducing unnecessary wear.

4. Acts as a medium for power interruptions:

   - When the vehicle starts or shifts gears, the release bearing ensures that the engine power is not directly transmitted to the wheels, so that the shifting operation can be carried out smoothly without causing impact between gears.

 Second, the clutch release bearing working principle

The working principle of the clutch release bearing is to make use of the return spring to keep the convex shoulder of the release bearing in contact with the release fork all the time, and at the same time, it can also be retreated to the last position to keep a certain distance from the end (about 3~4mm), so as to play the role of the clutch combining smoothly.

1. Clutch pedal action:

   - When the driver depresses the clutch pedal, the clutch release fork is pushed through a series of linkage mechanisms.

2. Push the release bearing:

   - The clutch release fork pushes the release bearing so that its front end pushes against the pressure plate.

3. Pressure disc action:

   - The release bearing pushes the pressure plate to release the pressure on the clutch disc, which separates from the flywheel and cuts off the power transmission.

4. Power transmission resumes:

   - When the clutch pedal is gradually lifted, the thrust of the release bearing decreases, the pressure disc presses the clutch disc again under the action of the spring, and power transmission is restored.

 Third, the clutch release bearing damage causes

Damage to the clutch release bearing may be caused by a variety of factors, mainly including the following points:

1. High operating temperature:

   - As a result of bad driving habits (such as turning or slowing down when the clutch is half-pressed for a long time), or the vehicle free travel adjustment is too large, making the clutch separation incomplete, in a half-engagement, half-disengagement state. This state will cause sliding friction between the friction disc and the flywheel, generating a lot of heat transfer to the release bearing, after the bearing is heated to a certain temperature, the grease melts or dilutes and flows, so that the temperature of the release bearing is further increased, and the release bearing is eventually burned out.

2. Lack of grease:

   - The clutch release bearing needs grease to lubricate. If the lubrication of the release bearing is neglected in the actual work, and no grease is added during the installation, it will lead to the lack of oil in the clutch release bearing, which will aggravate the abrasion and increase the temperature, and eventually damage the release bearing.

3. Improper free stroke:

   - If the clearance between the clutch release bearing and the release lever is not suitable (generally 2.5mm), the free travel on the clutch pedal should be 30~40mm. too small free travel or no free travel at all will make the release lever and the release bearing in a constant engagement state, increase the wear and temperature of the bearings, and reduce their service life.

4. Other factors:

   - Uneven adjustment of the release lever, deformation of the release fork, poor return spring of the release bearing, etc. will also have an effect on the damage of the release bearing. All these factors will cause the clutch to work against the release bearing, so that it is always in working condition and the temperature gets higher and higher, thus damaging the release bearing.

5. Prolonged semi-coupling:

   - Frequent operation in semi-coupling (e.g. in traffic jams) will cause the release bearing to remain in working condition for long periods of time, generating high temperatures and excessive wear.

6. Foreign matter entering:

   - Dust, moisture, etc. into the bearing inside, can cause corrosion and wear.

7. Improper operation:

   - Frequent and rough operation of the clutch, such as rapid acceleration and braking, can also increase the burden on the release bearing.

8. Poor quality:

   - The quality of the bearing itself, such as poor material or manufacturing defects, will also shorten its service life.

 Judge whether the clutch release bearing needs to be replaced.

To judge whether the clutch release bearing needs to be replaced, the following methods and steps can be carried out:

1. Listen to the sound:

   - Start the engine: After the engine is started, press the clutch pedal lightly.

   - Sound judgement: When the free stroke just disappears, if there is a squeaking or rustling sound, and the sound persists when you continue to press the clutch pedal, this may indicate that the release bearing has been damaged and needs to be replaced. If the sound disappears, the release bearing may be fine.

2. Check the free travel:

   - Depress the clutch pedal: Fully depress the clutch pedal and observe the pedal travel.

   - Compare the free travel: If the free travel is too small or there is no free travel, this may indicate that the clearance between the release bearing and the release lever is not appropriate and needs to be adjusted or replaced.

3. Observe other related components:

   - Clutch disc and pressure plate: since the release bearing, clutch disc and pressure plate usually work together, if the release bearing is damaged, the clutch disc and pressure plate may also be worn out. Therefore, when checking the release bearing, you should also check the condition of the clutch disc and pressure plate.

   - Release lever and release fork: Deformation or damage to these parts may also affect the proper functioning of the release bearing. If these parts are found to be defective, they should be replaced or repaired promptly.

4. Professional inspection:

   - Troubleshooting: If you suspect that there is a problem with the clutch release bearing but cannot determine it by yourself, it is recommended that you go to a professional automotive repair shop for troubleshooting.

   - Professional advice: The service technician will use professional tools and equipment to check the condition of the clutch system and give professional advice on whether the release bearing needs to be replaced.

5. Replacement criteria:

   - Average service life: The average service life of a release bearing is usually more than 100,000 kilometres. If the vehicle has been driven for a long period of time and is experiencing the sounds mentioned above, free travel problems or damage to other related components, then it may be necessary to consider replacing the release bearing.

   - Preventive maintenance: Regular maintenance and inspection of the clutch system can identify and solve problems in time to avoid excessive wear and damage to the release bearing.

 V. Common signs of clutch release bearing failure

Damage to the clutch release bearing may result in poor clutch operation or complete failure. The following are some common signs to determine whether the clutch release bearing is damaged:

1. Abnormal noise:

   - If you hear a constant buzzing, hissing, or other unusual noise when you depress or release the clutch pedal, this could be a sign of a damaged or worn release bearing.

2. Clutch pedal feel:

   - If the feel of the clutch pedal becomes unusually heavy or loose, this may indicate a problem with the release bearing.

   - A noticeable vibration or a ‘stuck’ pedal feel when the pedal is depressed may also be a sign of a damaged release bearing. 3.

3. Incomplete clutch release:

   - If the vehicle is still difficult to shift when you fully depress the clutch pedal, or if you feel a clunking sound when shifting gears, it may be because the release bearing is not fully disengaging the clutch.

4. Clutch slip:

   - When accelerating or climbing a hill, if the engine speed rises but the vehicle speed does not increase, this may be a sign of a slipping clutch, and a damaged release bearing may be one of the causes.

5. Difficulty shifting gears:

   - If you notice that shifting becomes difficult, especially when starting from cold, this could be a sign of a damaged release bearing.

6. clutch spring fatigue:

   - Damage to the release bearing may lead to clutch spring fatigue, which in turn affects the normal operation of the clutch.

 VI. Further Confirmation Methods

In order to further confirm whether the clutch release bearing is damaged, the following inspections can be carried out:

1. Visual inspection:

   - If possible, remove the clutch cover for inspection to see if the release bearing shows visible signs of wear, damage or poor lubrication.

2. functional test:

   - After the clutch cover is removed, the release bearing can be manually operated to check for smooth rotation and abnormal noise.

3. Professional diagnosis:

   - If the above methods fail to identify the problem, the vehicle can be sent to a professional repair shop for inspection and diagnosis using professional tools and equipment.

Summary

The clutch release bearing is a key component in the automotive clutch system, and its normal operation is crucial to ensure the performance and life of the clutch. Therefore, drivers and maintenance personnel should regularly inspect and maintain the clutch release bearing to avoid the occurrence of the above mentioned damaging factors to ensure the safety and reliability of the vehicle. I hope this information is helpful to you!