Spongy Brakes

[killer_mike]

Hey guys, i bled my brakes, got all the air out [as far as i can tell] but when the booster kicks in the brakes turn out spongy; i have a disk/drum set up, the booster i think is a 8-9 inch GM, the hoses are new, the entire brake lines are new along with the fittings, all its tight, no leaks.
I have a K10 67, long bed. But this is not any help because my truck dont come with disk on the front. Everything is pretty much custom.

But i dunno why the brakes are spongy, im thinking the booster might be messed up, or theres a possibility theres air in the lines.

Thanks.