The classic symptom of wear in the clutch release bearing is clutch squeal, noticeable when the clutch pedal is pressed, and before then a whirring sound may be heard with the clutch pedal down. The thrust bearing only functions with the clutch pedal engaged and even without clutch slip, using the thrust bearing as a footrest will cause unnecessary wear, so it's best to avoid this habit. To remove the thrust bearing, the gearbox has to be removed and this is possible by removing the release fork in which the thrust bearing is housed; in the case of M45 gearboxes, it is held by a spring clip. To check the bearing, lay it on a bench and rotate the bearing under slight pressure, it should turn smoothly without binding or play. If there are any questions about its condition it should be replaced completely because the assembly is not breakable to make way for a new bearing. When getting a replacement, it's important to specify the type of clutch as thrust bearings are different for different types. The installation process follows the reverse of removal and the clutch lever free travel should be adjusted accordingly.