if you have a clogged line you would have a hard time turning the steering wheel because there wouldn't be fluid ps fluid flowing through your gear box. when you replaced your gear box and lines did you drain all the old fluid out of the ps pump and resivoir and fill with new fluid? if the old fluid is dirty and contaminated it can cause seals to go out pretty quickly.

 

Ok so I tore it all apart and installed a new seal kit. I then flushed the ps pump, reservoir, and lines for the 2nd time. Hooked it all back up with some fresh ps fluid and so far so good. Not sure what was causing the problem. It could have been dirty fluid or maybe just another faulty steering box.

 

hopefully that works for you. i'm guessing your old fluid was dirty. i've had dirty fluid destroy seals in less than 20 miles.