Guys, I'm loosing my mind, perhaps someone out there can tell me what the heck is going on.
My steering box upper seal on my 1964 Thunderbird has been leaking for years and I finally decided to fix it. I took out the box (no fun) and had it rebuilt by a family owned company in Detroit that has been rebuild these boxes since the 50's.
I picked it up and installed it. Almost instantly the engine was started, the top seal blew out throwing steering fluid all over the engine bay - NOT GOOD. I of course called the re-builder the next day and he said that he had never heard of such a thing but he would take another look at and see what happened. I personally was there when he replaced the seal and pressure tested the box to over 1,000 lbs. (almost twice what the pump puts out)with no leaks whatsoever.
I take the box home and again install it. The engine starts and I run it for about a minute or so and the box is perfect - no leaks. In order to bleed the system I began to move the steering wheel back and forth. As I do this, I heard a noise coming from the steering pump. Assuming the pump reserve was now dry I added fluid to the reservoir to bleed the system. As I add fluid the noise is VERY loud and the top seal again blows sending fluid once again all over!! NOT HAPPY!
What the hell is going on here? It can't be the box because it was tested and it should not be the pump because I never had trouble with it in the past. Sounds to me like the pump or box or line is constricted or blocked in some way. Where do I start???? Did I screw something up? I need help indeed, thanks for all replies.

Assuming you have the hoses connected correctly it sounds like the pressure regulating/relief valve in the pump is not doing it's job. A gauge in the pressure side hose will tell the tale....Bob

Bob, yep, that's what I was thinking.................looks like I'd better yank the pump.