Looks like by the picture you broke the head off one rivet and maybe the other four are loose. Looks like you could have bent the face of the drums at the rivets. You must use a  a puller that threads  into the stud holes, That way the pulling pressure is in the center of the drum. My puller pulls on all the studs at the same time.

No, I don't mean the pin for centering the wheel, if you look at the photo, you will see the tabs that go around the center of the drum.  These tabs are what broke.

Hope this explains it better, a mechanic I ain't, but I try:)
Bob

Bob, I don?t have my car on hand, but I remember only one long pin. Others ware short as on Yours. If so, You have only one broken - in 1 o?clock position. Look, if the others aren?t enough to center the wheel.
Good luck! Go

I had to remove the passenger side brake drum to replace the wheel cylinder, when I went to reinstall it yesterday, I noticed that most of the center tabs  were broken.  I must have done it when pounding on the drum puller to remove the drum.

Luckly I have spare rear drums.

What did I do wrong if anything?

Has anyone ever had this happen to them?

Thanks in advance,
Bob