Clutch release bearing and its noise problem analysis

 I. Definition of clutch release bearing

Clutch release bearing, also known as Clutch throw out bearing, is a key component in the automotive clutch system. Its main function is to push the clutch pressure plate when the driver depresses the clutch pedal, so that the clutch disc separates from the flywheel, thus cutting off the power transmission between the engine and the gearbox. This process makes shifting smoother and reduces the feeling of impact when shifting.

 Second, the causes of clutch release bearing noise

There may be various reasons for clutch release bearing noise, the following are some common reasons:

1. Bearing wear:

   - Cause: Prolonged use and frequent clutch operation will lead to wear of the clutch release bearing, which in turn generates noise.

   - Symptom: A rubbing or clicking sound may be heard during operation.

2. Lack of lubrication:

   - CAUSE: The clutch release bearing requires proper lubrication to reduce friction and wear. If there is a lack of lubrication, the bearing will make a noise.

   - Symptom: A sharp rubbing or whistling sound may be heard during operation.

3. Foreign matter enters the clutch release bearing:

   - Cause: Dust and impurities enter inside the bearing, which can cause irregular rolling and generate noise.

   - Symptom: Irregular clicking or whistling sound may be heard during operation.

4. Improper free travel of clutch pedal:

   - CAUSE: If the free travel is too small, the release bearing may continually contact the pressure plate, causing excessive wear and noise.

   - Symptom: Clutch pedal operation feels abnormal, accompanied by noise.

5. Abnormal clearance between the inner and outer circle of the bearing and the journal or bore:

   - CAUSE: When the fit clearance between the inner and outer circle of the bearing and the journal or bore is too large or too small, it may cause noise when the bearing is running.

   - Symptom: Vibration sound or irregular noise may be heard during operation.

6. There are pockmarks or ablation marks on the bearing balls and inner and outer seat rings:

   - Cause: These damages can cause the bearing to run unevenly, resulting in abnormal noise.

   - Symptom: Irregular rubbing or clicking noises may be heard during operation.

7. Clutch release bearing is improperly installed:

   - CAUSE: Improper installation or inaccurate location may also cause the bearing to vibrate and make noise during operation.

   - Symptom: Vibration or irregular noise may be heard during operation.

8. Wear on other parts of the clutch system:

   - CAUSE: Wear of parts such as the clutch pressure plate and clutch disc may also cause bearing noise.

   - Symptom: Irregular rubbing or clicking noise may be heard during operation.

 Methods to deal with clutch release bearing noise

For the noise problem produced by the clutch release bearing, the following treatment methods can be taken:

1. Check the lubrication condition:

   - Methods: first check the lubrication of the bearing, if you find that the grease is dry or insufficient, you can add an appropriate amount of special grease.

   - Effect: It helps to reduce the friction and wear, thus reducing the noise.

2. Adjust the freewheeling stroke:

   - Method: Ensure that the clutch pedal has the correct amount of free travel to avoid constant bearing stress.

   - Effect: Reduces excessive wear on the bearing and reduces noise.

3. Replace the clutch release bearing:

   - Method: If the clutch release bearing is already badly worn, the most direct solution is to replace the release bearing with a new one.

   - Effect: Restore the normal working condition of the bearing and eliminate noise.

4. Cleaning and inspection:

   - Method: Clean the bearing and its related parts and check whether there is any foreign matter or damage.

   - Effect: Ensure that the inside of the bearing is clean, running smoothly and reducing noise.

5. Inspection of related parts:

   - Method: Sometimes the noise may be caused by problems with other parts (e.g. pressure plate, clutch disc), which need to be checked together.

   - Effect: Ensure the normal operation of the whole clutch system and reduce the noise.

6. Adjust the fit clearance:

   - Method: If the noise is caused by an abnormal fit clearance between the inner and outer circle of the bearing and the journal or bore, the fit clearance needs to be adjusted to an appropriate range.

   - Effect: Ensure smooth running of the bearing and reduce the noise.

Summary

The clutch release bearing is a key component in the clutch system, and its normal operation is vital to ensure smooth clutch disengagement and power cut-off. However, due to various reasons (e.g. wear, lack of lubrication, intrusion of foreign matter, abnormal fit clearance, etc.), the clutch release bearing may generate noise. These problems can be dealt with by adding grease, inspecting and replacing the bearing, adjusting the fit gap or replacing the relevant parts. During treatment, make sure to follow the vehicle manufacturer's guidelines and recommendations and operate under the guidance of a service professional. Through proper maintenance and treatment methods, the service life of the clutch release bearing can be extended and the inconvenience and safety risks caused by noise problems can be reduced.