Hydraulic throwout bearing clearance is the clearance between the hydraulic release bearing (or hydraulic throwout bearing) and the clutch fork. Proper clearance of the Hydraulic Throwout Bearing is critical for proper clutch operation. The Hydraulic Throwout Bearing requires an air gap for initial installation, typically 1/8 inch to 1/4 inch, approximately 3 to 4 millimeters . This clearance disappears when the clutch system is drained because the bearing will contact the clutch fingers when the system is filled with fluid, but will not exert pressure on them .

To adjust the hydraulic release bearing clearance, specialized tools can be used to accurately measure and modify the clearance. For example, some tools have a scale with each line equal to 0.100 inches, and the clearance should be read from the edge of the O-ring, not the center. If the clearance is found to be too large, it can be reduced by adding shims.

In addition, the total allowable clearance for hydraulic release bearings is typically between 0.100 inch and 0.150 inch. If the bearing assembly is too short, it will be necessary to tighten the bearing assembly until the proper clearance is achieved. This design allows the hydraulic release bearing to be self-adjusting within a range to accommodate the specific needs of different vehicles.

If the hydraulic release bearing clearance is too small, the bearing will continue to wear the fingers of the pressure plate, and in extreme cases, if pressure is continually applied to the fingers, the clutch may not be fully released, resulting in continued clutch slippage and accelerated wear . On the other hand, if the clearance is too large, the hydraulic release bearing may extend excessively during the pedal stroke, which can damage the bearing seal and may lead to hydraulic fluid leakage .

During installation, care should also be taken not to use hammers or other hard objects to directly strike the bearing or related parts, as this may damage the bearing or cause deformation of the mating surfaces . The control of mounting strength is also very critical to avoid excessive force or wrong mounting direction that may cause tilting or damage to the bearing.

After mounting, it is necessary to check the rotational flexibility of the bearings to ensure that the bearings rotate smoothly and there is no blockage. If the bearing is not flexible or has abnormal sound, the cause should be identified and dealt with in a timely manner.

Preparation of hydraulic release bearings, inspection of mating surfaces, preparation of mounting tools, proper use of hydraulic tools, avoidance of tapping, control of mounting strength, attention to bearing clearance and preload, as well as post-mounting inspection and maintenance are all key steps to ensure the quality and service life of the bearings.

In summary, proper installation and clearance adjustment of hydraulic release bearings is critical to ensure proper operation and extended service life of the clutch system and requires precise adjustment and maintenance in accordance with the manufacturer's recommendations.