Abstract: A shaft seal assembly for establishing a liquid-tight seal between a steering knuckle and an axle shaft is provided. The shaft seal assembly includes an outer case and a first elastomeric member attached to one another. The elastomeric member has a castellated feature including a plurality of projections extending in a radially outward direction and separated from one another by a plurality of grooves. When the shaft seal assembly is installed in the steering knuckle, a cavity is presented between the steering knuckle and the first elastomeric member. Together, the grooves and cavity allow air to flow from a hub on one side of the seal assembly to a vacuum port in the steering knuckle. The cavity extends circumferentially around the seal assembly, and thus, air flow from the hub to the vacuum port is not dependent upon the orientation of the seal assembly relative to the steering knuckle.

Abstract: A shaft seal assembly for establishing a liquid-tight seal between a steering knuckle and an axle shaft is provided. The shaft seal assembly includes an outer case and a first elastomeric member attached to one another. The elastomeric member has a castellated feature including a plurality of projections extending in a radially outward direction and separated from one another by a plurality of grooves. When the shaft seal assembly is installed in the steering knuckle, a cavity is presented between the steering knuckle and the first elastomeric member. Together, the grooves and cavity allow air to flow from a hub on one side of the seal assembly to a vacuum port in the steering knuckle. The cavity extends circumferentially around the seal assembly, and thus, air flow from the hub to the vacuum port is not dependent upon the orientation of the seal assembly relative to the steering knuckle.