Sticking brake pedal

I'm going to start with, I have tried everything. After I finished replacing my brake pads I noticed my pedal went down to the floor, bled the system a few times and noticed it still happened. Looked in a few spots, and determined the brake booster went out. Got it, replaced it, bled it and problem not fixed. Determined that the master cylinder went out because where MC meets the Booster, there was an air leak WHILE IT HAS A GASKET. Took the gasket off and still problems. Finally I bled the system so much I went through 2 bottles of brake fluid, never got passed the min fill line.
The brakes were fine after the MC replacement BUT the damm pedal was sticking the first 1/4 inch and then the brakes worked fine. Took out the MC greased the rod AND the inside of the booster still problem persists.

Things I have done to try and fix the problem
• replaced MC
• replaced Booster
• replaced brake pads and both Front Calipers
• replaced vacuum lines
• realistically bled about 40 times, no air in the system whatsoever.
• bench bled the MC before installation
• Adjusted the brake pedal to manual Specs
• Greased the hell out of the brake pedal components.

This is a long post and any help you have will be greatly appreciated. I have looked high and low and cannot find help for this. I am out of options please help.