no brake pressure? S14 base

[InzaneSR20]

well i just got my pads on, i took the one rear piston out of the housing to remove some rust on it. I also opened the bleeder valve. I put it back together, but now i dont have any brake pressure. So my dad and me start to bleed the brakes, and where out there for like 10mins and still nothing. Anybody got any ideas?

[navysnail]

is it out of fluid, as in did you remember to keep filling it up and bleed all calipers