2000 ford taurus powersteering issues

i have a 2000 ford Taurus 3.0L. this is the issue the powersteering went so i changed the pump. i also changed the rack then put a brand new pump in. and it is still giving issues. the fluid foams and when i turn engine off it blows the cap off and fluid backs up. i have no idea why this is happening. only thing i can think of is that a line is pluged. could someone please help with ideas.

Thank you. did u bleed the air out of the power steering system after replacing the rack and pump? i have been trying it says in the book to turn wheel side to side. how long must this be done. the way to do it is to support the car on jackstands with both front wheels off the ground. take the cap off the resevoir and start the engine. while its idling, turn the steering wheel back and forth slowly, allmost but not quite to the stops on the left and right. keep doing this until the bubbles and foaming disappear in the resevoir and the fluid looks clear. u may have to add fluid as u go to keep the resevoir full. it goes faster if u got a helper, one to watch the resevoir and add fluid as needed and the other to turn the wheels.

if u replaced both the rack and pump its likely there could be a lot of air in there, so this may take awhile. youll know your making progress once the foaming starts looking better. turning the wheels slowly is the key here.

its a little late for this now, but if i replaced both the rack and pump i would of replaced the hoses at the same time, just to prevent leaks later on. it aint likely that a hose is plugged, we dont usualy see this with p/s hoses. Thanks connie i guess i will just have to keep trying this one more question i have is as soon as the engine starts the pump sucks all the fluid in so i dont know what level it will be at. sounds like theres lots of air in there. and u wont be able to bleed it til u can keep fluid in the resevoir.

start the engine and add fluid as it idles, til the resevoir is full. then do the bleeding operation like i described.