When you press on the brake pedal, there is nothing there until it almost hits the floor, and then they are incredibly weak. Could it be that the master cylinder is bad, or maybe that a line is bleeding through? I am getting ready to buy this vehicle and i was just curious as to what was wrong with it. Thanks, Robert

 

Hear any noise like a vacuum leak?

 

could be a possibility, maybe that is why the when you rev it up, it takes a long time for the rpm to come back down

 

I would think it is the brake booster if you can hear a vacuum leak.
You can get a new master cyl/brake booster for under $150.
See any fluid on the ground? I know that the brakeline that runs along the frame for the rear brakes is bad about rusting out.

 

I couldnt hear any vacuum leak, and i didnt see any fluid either, but the guy said that it was out of fluid and he filled it up, so maybe they just need bleed. When the vehicle is off, the brakes pump up a little bit but not much at all. I dont think that it would even be enough to stop it.

 

The fluid just doesn't disappear in a sealed system. It had to go somewhere.
Check the drivers side frame rail at about the start of the bed and see if it is wet. Thats the only brake problem I have had on the truck I have now.

 

you see, thats the thing, i pumped the hell out of the brakes and the fluid level never changed

 

If you are real worried about it spend $20 on some speed bleeders and bleed the brakes before you buy it. I have done crazier things that that when looking at cars. Wait till you have a guy sitting beside you when you rev it up in 5th gear and dump the clutch. He will get a strange and kind of mad look on his face.