Ok so i decided to replace my brake master today . So i pulled my old one off and took it down to my local autozone and swapped it in as a core and got a new one. I get it home and go to install it and notice it looks different. It looks like the old one had some sort of spacer on it. So i look online and found this picture
So I then think my old master cylinder still has it on it. wtf can I do? please someone help me out please. I feel like such an idiot right now.