I have recently done two of them.
Don't try to remove the whole flipping mechanism. You want to remove only the seal.
Sometimes they just pull off a little ball on the end of the little flipping bucket. Sometimes they are screwed on.
On the first one, I had to carve the seal away from little ball with a sharp jack knife. Be careful because you are working nearly blind. It helps to examine it closely first so you know what you are feeling. The second one I was able to just pull off. If it screws off a stud, you may have to get a pair of pliers to unscrew the little nut after you cut the seal off.
On mine, the new on just pressed onto the little ball end.