Brake fluid on firewall

Ok so I bought my 73 dart 4 door a week ago. Good bones, but needs some love. Anyways, when I first drove her, the brake pedal was a little spongy, but nothing too major. When I checked the master, the fluid looked like it may never have been changed. after I bled the system the brakes got worse, and are now non existent. I've now bled it twice, and never saw any obvious leaks, and stopped getting bubbles in the bleed, but then while working on some wiring under the dash I noticed a bit of brake fluid on the cabin side of the firewall under the brake pushrod.
So at this point I'm pretty sure it's my master cylinder, but I thought I'd check in and see if anyone had anything else I should check.