IHUD, I do believe you are mistaken. The vacuum port is not located in the wheel bearing hub assembly, it is located in the assembly that supports the upper and lower ball joints. The wheel bearing assembly bolts to this support but it is not part of it. When you cut the wheel bearing assembly in half, you can see that the grease you would get by using the vacuum port would only go around the top of the bearing. Just because the vacuum port is located roughly where the middle of the wheel bearing is, the bearing is still sealed and grease cannot get into it. It is sealed 360 degrees in all directions.