I've got a Saginaw PS box, 800 I think they call it, and a Saginaw P pump. I rebuilt the box, didn't touch the pump. When I put it on, I went through the bleed process, but never saw any bubbles in the reservoir, the fluid level didn't go up and down, and everything seemed to be working smoothly. I had filled the box with fluid as much as I could before I closed it up, and filled the reservoir with fluid then let the truck set for a week while I worked out other issues. I figured maybe the PS fluid had time to work its way down to the box and maybe this is why there didn't appear to be any air in the system. I had to make my own fluid lines and since I had never tried brazing before, the first time I set the front wheels on the ground I didn't make it out of my driveway and one of the lines busted. So I took it to someone who new what they were doing to get it fixed and reinstalled it.

Now here's my problem. I drove the truck about a mile to the neighbor's house and when I was leaving, the wheel jerked suddenly to the left and I couldn't get it to turn right at all. I checked the fluid and it was a little low, so I topped it off. I couldn't honestly say whether or not it had puked any out. I got it home and put it back up on the jackstands. All the lines looked to be intact and I didn't see any leaks. With the truck running, I could turn the steering wheel to the left, but I could not turn it to the right. Then I realized that I can't even turn the steering wheel to the right with the truck turned off. But I can turn the front wheel easily all the way to the right by hand. What I mean is, by actually pushing on the front tire and wheel, not with the steering wheel. When I do this, the fluid level in the reservoir come way up. (The first time it overflowed a little.) So I thought maybe there's a big air bubble in the system, so I started turning it slowly all the way to the left, then shutting the truck off, turning it to the right with the wheel, starting the truck and repeating. After a while, I found the I could get to turn part of the way to the right after getting it all the way to the left, and then it would stop and I would have to shut the truck off and start over. Then I tried just turning it left from all right to center, and then back to right again. This was working so I kept at it, going a little more past center each time. But I was starting to notice that it seemed to be pulling a little to the right now, and at one point it jerked out of my hands and turned all the way to right lock and then spun back to left lock.

Kind of creepy. What the hell is going on? I've Googled my fingers off, but I can't find anything like this. Sure would like some help on this.

Thanks.

 

I agree, that is odd. Sounds like it could have something to do with the steering gears valving. The sector shaft also needs to be properly adjusted as well, to properly mesh with the worm gear. If they are too tight you could release some shavings into the box that could potentially be causing the problems. All this is just an educated guess though.

Why did you rebuild the box? Was it leaking? Or did it have some other symptom?

 

It was leaking as detailed here, then I ended up getting a donor box at the junkyard and putting the guts of my old box into it.

I took a video of what it's doing. Should be able to get that up tomorrow.

 

I made a video so you could see what the truck is doing. I'm still new to editing YouTube videos, so I got my "rights" and "lefts" mixed up a couple of time and haven't got any captions in there yet to correct it. But you can still see what's going on. I was kind of concerned about the check valve on the donor box and I was thinking maybe it was stuck open. But whenever I Google it all I can get back is info for the fluid control valve on the pump. It's number 49 and 50 in this exploded view:



Anyway, so here's the video: