1995 W900L power steering

Good morning everyone,
Ok here is our issue. We had a driver in our truck who said the front end needed to be greased. Well once my old man got in the truck and drove it he was able to tell that it wasn't a lack of grease issue but that it was a steering issue. So he and our mechanic checked the U-joints, they are fine. The gear box was replaced not that long ago. They decided to replace the power steering pump since it was the original. Well after replacing and bleeding the lines there is still a "bubble" that it will fit my hubby when trying to turn and the steering wheel will not turn back on its own. Any thoughts?? We are at a loss and are working the phones with the people we have bought the parts from.
Thanks!

 

Thanks Qualitytruck. The kingpin and bearing have already been checked. As soon as he gets home we are checking the gear box (great for the holiday weekend! lol). I appreciate the feedback.

 

We have bled the lines, several times to double check that. It just hits a point, even driving down the road, where it sort of sticks for a minute and then it will go. It doesn't do it at the same position every time. He should be home tomorrow and the gear is next on the list (although that was replaced fairly recently). The u-joints, king pin, bearings are all good so replaced the steering pump and that didn't do it.....ugh

 

Thank you. I will let him know about that! Your description is exactly what it is doing!!! I really do not want to have to put a new gear box on it at this moment in time!! Everytime I talk to him he likes to say "All the other truck drivers have power steering" I am beyond tired of hearing that one! lol