Hold on...
My experience shows that when you pop the PS cap with the truck on you'll get exactly what you stated, especially once air is introduced into the system with a leak. There's quite a bit of pressure in the return line. Now that you replaced the hoses do you still have a puddle of PS fluid after it sits? The only place you could be losing fluid from the PS pump is on the main seal to the engine block, and I find that hard to believe as it's protected by a metal lip on all sides. If you no longer have a puddle, yet still don't have power steering, you more than likely only need to buy a rebuild kit for $10 IIRC and replace the inner seals. If you still have a puddle, try and track down the leak, maybe on the cooler as Rick suggested.