'92 Buick Lesabre Limited - brake fluid leak issue

[ComputerProgrammer]

Hey guys, I'm new to the forums and couldn't find a set of rules for posting. I'm not sure if this forum is more for fixing or working on cars. I've been having trouble with my Buick's brakes and wondering if anyone knows about it...

I currently have no brake fluid in my car because it keeps leaking out (leaks while actively being used). The leak is between the power brake booster and the brake master cylinder... Is there any type of gasket I can get to better fill the gap between the two pieces of metal? Is there some way to tell which of the two pieces is creating the leak to narrow down which to purchase?

If anyone has any idea, please let me know!

[maxwedge]

The rear seal in the master cylinder is bad, you need a new master, and a complete brake bleed.