Geberit 816.418.00.1 Replacement Flush Valve Base Sealing Washer - Clear

Geberit flush valve won't seal properly and is constantly passing water into the toilet pan but there is no sign of an inlet valve failure, it could very well be that the base sealing washer need to be changed. Overtime as the flush valve is opened and closed, small imperfections tend to occur in the surface of the rubber washer causing the washer to be warped and not providing an adequate seal.