When is a defective clutch release bearing usually heard?

A defective clutch release bearing is typically most noticeable when the clutch pedal is depressed to take up any freeplay. At this point, the bearing is under load and is actively engaged with the clutch assembly. If the bearing is worn or damaged, it may produce a noise, such as a squeaking or grinding sound, which can be an indication of its failure. This symptom manifests specifically when the bearing is trying to relieve the pressure on the clutch disc while allowing it to disengage from the engine.

When the clutch is not engaged or when the vehicle is idling in neutral, as is the case in some of the other scenarios, the bearing is not under the same operational stresses, resulting in reduced likelihood of noise. Similarly, in gear or while taking off, the vehicle's engine dynamics may mask any sounds from the clutch assembly. Thus, hearing a noise specifically while taking up freeplay is a key diagnostic indicator pointing to a failing release bearing.