If you have a wedge, this is often a leak point as well and one I always forget to suggest. The base is screwed through the wedge and should be secure to the roof so all the other interior components are removable. There is an 11/16" nut way up the inside shaft near the roof that must be loosened and removed to remove the entire antenna assembly if that's what you are looking to do. This requires a special tool to access or can be made with a deep socket 11/16" and something to fee it up there. If you are sure that's where the leak is coming from you might just be as well off waiting for a few dry days and scraping and resealing all around the base, the wedge and the roof.