A valve assembly for an implant has an inner shell, a self-sealing material disposed within the inner shell, and an insertion pathway extending through the self-sealing material. At least one gap is formed in the self-sealing material that intersects with the insertion pathway to define a proximal pathway section and a distal pathway section. A filling tube is passed through the valve assembly for filling the outer shell of the implant with a fluid. After the implant is filled, the filling tube is removed. As the filling tube is removed, if the self-sealing material within the distal section of the pathway is unable to self-seal before the fluid reaches its proximal end, the fluid is diverted into the gap. The time that elapses before the gap is completely filled by the fluid provides sufficient time for the self-sealing material within the proximal section of the pathway to self-seal.