Power steering leak...

2002 F250 7.3L Auto

Simple question....

Engine off, turn the wheel from one side to the other, should the truck puke out steering fluid? I've never seen this before...

Yeah,normal.

How can this be normal?

The steering fluid reservior usually has a large area above the full mark to handle the reverse flow from turning the wheel with the engine off. If it has too much fluid, or the reservior was not designed correctly, it will come out the vent hole in the top of the cap. When turning with the engine off, the fluid goes the route of least resistance. Since the pump is not moving, the fluid doesn't want to go past it to loop back through the system, so it goes to the reservior. Too much fluid or too little capacity, and you get a bubbling up mess.

If you have a large enough capacity (I'm not familiar with whether that year has a problem) and aren't over filled, then there could also be a different problem in the system. Have you noticed anything when driving? Turning with the engine on and stopped but in gear, dragging down the rpm's in one direction and the power steering pump whining? You could have pump problems, hose/line kinked or clogged, power steering cylinder valve issues.

Just to keep it simple when the engine is stopped the pump isn't turning. So all the fluid in the return line is being forced back to the pump when you manually turn the wheels. Theres nowhere for that fluid to go after it takes up whatever space is left in the reservoir but out the vent hole in the cap.

This has happened to me when the resevior is overfilled just slightly.

This has happened to me when the resevior is overfilled just slightly.

Has nothing to do with over filling. Every 7.3 SD I have ever seen will puke it with the engine off. My 97 would not, it was a vacuum brake booster. The SD trucks use a hydrobooster, they run off the power steering. I am guessing the extra fluid capacity overwhelms the system. As said already, all the returning fluid will take the path of least resistance, that is just how hydraulics, electric anything works. The easiest path if the engine is off is to overfill the resevoir and run out the vent....