No brake pedal pressure, even with car off.

[BoostnBenz]

As the title states I'm having problems building up any pressure with my brakes. When I got the car a month and a half ago I didn't notice this problem at all, last time I ran it I noticed it didn't feel right. But now it is awful, it almost can't hold the car back at idle. Before I try to fix any other problem I'd like to have this working correctly. At first I thought it was just something on my front rotors, but I just packed the bearings and went out of my way to make sure the rotors were oil free when I put it back together.

Here is what I know so far. Car only stops after pedal goes down a few inches, from that point it cannot be moved further. However, it will stop the car like that. When I MASH the brakes the rear tires sound like they lock up, but the fronts don't seem to be putting any effort into stopping. There is approx 19" of vacuum at idle. Like I said in the title, even with the car off the brake pedal doesn't harden up. If I pump the pedal enough I will sometimes get a little bit of pressure, but it just fades away in an instant. The rotors are now clean metal on all 4. I've never changed the brake fluid in it, knowing the last guy he probably didn't either. So I assume it has been about 3-4years since it has been changed. Is it possible the fluid has froze? Or is it likely an internal seal has quit working and it needs to be replaced?

Thanks,
Jeff M.