The pneumatic clutch press specifies plus or minus 10 degrees near the top dead center as the default top dead center. Because the braking angle of the friction clutch has a certain degree of error, it is impossible to stop at 0 degrees accurately every time, so the top dead center angle range is specified. If the slider stops outside this range, it will display "Overtravel". When overtravel occurs, the slider can stop to the top dead center again by inching function. If it happens frequently, it is necessary to adjust the gap between the clutch and the cam that stops braking.