Now that I (excuse me, I mean we, and you know who you are, and if you don't know, it'* Danthurs) got it started, the brakes seem to be a little stubborn from sitting for a year and a half. Way low on fluid, you can see where the fluid leaked out. It leaked out between the master cylinder and the vacuum booster. You can see the big stain mark down the front of the booster. I had this problem not too long ago and replaced the master cylinder, so it'* fairly new. The problem is that I have basically no pedal, you have to pump them a couple of times, now I realize it needs to be bled, but even after bleeding the next day it'* mushy again. Also after you pump it and it begins to stop the driver front brake caliper locks up to stop the wheel. Where should I start, New Vac Booster?, new caliper or rebuild the one there? flush lines? please let me know you ideas. Thanks 2ringer6

Replace the drivers side. I suspect a bad piston and that'* letting air in the system. Also, a total change of the brake fluid. I'm sure I did a write up on changing the master cylinder. Here it is.

https://www.gmforum.com/t279220/

What do I do about the leak between the master cylinder and the vacuum booster?

You need to determin where it'* leaking. After you remove the master cylinder you can then see if you can rebuild it, or have to replace it.

I replaced the master cylinder not long ago, do they start leaking again so quickly. Could it be the booster?

Is it brake fluid that'* leaking? You will need to inspect the master to see if you can find the leak.