1979 no brakes, no fluid

[Miiller78]

I got into my 1979 T Bird and it fired up and I went to put it in gear and no brakes. I got out and checked the fluid levels and both reservoirs were empty and it looked like there was fluid in the lines yet. Y’all have any ideas of a cause for this?

 

[74 Harley]

Most likely your master cylinder is bad, your booster is probably full of brake fluid.