Quote Originally Posted by 00tec View Post
Wait, you work on cars?

I would tap that retainer ring a little flatter, then press it on the pad. Maybe use a small socket as a punch around that center to press the retainer down (and in)
This. Take the plate off, flatten the retainer, and then put it back on using a socket just larger than the post.

You might even be able to just flatten the retainer while it is already over the post using a socket.