I've got an '87 GMC Jimmy that had a leak in the input shaft on the steering box. I pulled the piece with the input shaft seals off, and replaced the seals, but I somehow managed to destroy the threads on it before getting it back in. I got another one from the junk yard, replaced the seals, put it in, and got everything put back together. Well, I finally finished dealing with the other issues I was having with it, and got it started for the first time in a month today. I was rather pissed to discover my steering box is now completely non-functional.

It is more than just a little screwy. If I turn the wheel to the right, the steering box kicks in, and yanks it further to the right. To the left, and nothing happens. And in either situation, the tires don't budge. I obviously screwed something up pretty badly, but I'm not sure what. I will say, I've got more than an 1/8th turn of slop in the wheel, but it was like that before. The good news is it doesn't leak at all anymore, but that's fairly pointless if the box isn't working.

Does anybody have any idea what I screwed up, or how to fix it. I can probably get another from the junk yard if absolutely necessary, but a new one is out of the budget right now, and another from the junk yard would probably need the same seals replaced, likely landing me in the same spot.

 

At the bottom of the torshion bar there is a rotary valve that uncovers pressure ports in the case. The rotary valve is not synced with the ports and thus no assist in one direction and high assist in the other. I use tapered pins and a home made jig to reassemble.

 

I decided given the age of the box, the discovery that it is also leaking quite badly from the pitman shaft, and the slop in the steering that its just time to replace the thing. I should be able to use any other Saginaw 800, yes?

 

Yup 800 will fit some have 4 mounting ears some 3. Three main ratios 12.7 ; 14.0; & varyable 16,14.
Pitman arms come in 2wd 4wd and police. There are two types of fittings, I think, there is flair and O ring and are easily interchanged. A lot of slop that guys try to adjust out is pitman SHAFT slop not sector gear play. Dont worry!

 

I've got an 800 with 4 screw holes. Is the smaller ratio quicker turning? I'd like to try to get a tight ratio steering box if I can find one. I'm going to keep the pitman arm I have now as I read that its best to keep as much of the original steering as possible to keep everything aligned properly. My pitman arm is flair I think, it has a clamping bolt? The slop is also definitely in the box. With the box out now, I can turn the input shaft nearly a quarter of a turn with no affect on the output shaft. Not good.

 

The lower the number the faster the steering. Also affected is lock to lock. A 12.7 : 1 box is about two and half turns LtoL. Tubing fittings are either flair or O ring. The pitman to sector shaft is about a seven degree taper.

 

I managed to find a box out of an 88 GMC Suburban that looked basically brand new, no signs of leaking fluid at all. It was one of only a small handful of boxes that I found that were identical to mine. Most of them use a big nut on the shaft to hold the pitman arm on. Mine uses a notched shaft with a bolt through the pitman arm to hold it on. I was hoping to find a box out of a newer GM truck that would work, but I guess all the new GM trucks have the boxes on the inside of the frame, where mine is on the outside. The new box I got seems to be in good order though, very clean, and on top of that, it has next to no slop at all, which is good. I'm sure its a 14.0:1 box, but I'll check tomorrow.