I went through this last year. I even had Ryan at Gateway call Big Dog about them, and they were $14 each. They call it a rotor button kit, meaning that you geta button,washer,and e clip. Take your rotor buttons out and see if they are grooved where they ride on the rotor.
I bet that if you try and cup the spring washers some they will tighen up. I did this and it worked fine, and it savewd me $140. I used 2 sockets to do this.
use a socket that is just smaller than the outside diameter of the washer, and a socket slightly larger than the inside of the washer and hit the center just a little to cup the washer.