What Causes a Clutch to Fail to Disengage?

[McDawson]

There are several reasons why a car clutch may not disengage completely: 1. Excessive free travel of the clutch pedal reduces the distance the release bearing pushes the release lever forward, consequently shortening the travel of the pressure plate backward, preventing the clutch from fully disengaging. 2. In a dual-plate clutch, if the adjustment screw is too close to the intermediate drive plate, it limits the rearward movement of the intermediate drive plate, causing incomplete separation from the front friction disc. Conversely, if the adjustment screw is too far from the intermediate drive plate, excessive rearward movement may cause the intermediate drive plate to collide with the rear friction disc, also resulting in incomplete disengagement. 3. Significant differences in length or stiffness of the front pressure plate springs, damaged springs, uneven spring hole depths, warping of the inner or outer clutch disc assemblies, or loose rivets can cause the radial and axial runout of the clutch assembly to exceed specifications, leading to intermittent contact. 4. Improper adjustment of the gap between the hydraulic cylinder piston and the push rod in a hydraulically operated clutch.