Steering Boxes

Croatan_Kid

Croatan_Kid

How's your hammer hangin'?
Joined
Nov 4, 2007
Location
New Bern
It's time to replace the steering box, pump, and lines on my 99 Silverado 1500. I've got the famous "weak right turn" thing going on and it has only gotten worse since the SAS. What I've been looking at is replacing the steering box with one from a 2500/2500HD. The reasoning behind this is the design of the box itself. The 2500 box is much easier to use with hydro assist, which I will probably do in the near future.

Now then...I can verify that the sector shafts are the same (diameter) because the pitman arms are the same part numbers. I can also see that the inputs on the boxes are the same as well since they use the same steering shaft part numbers. The only thing I don't know for SURE is if the 3-bolt pattern where the boxes bolt through the frame is interchangeable.

Atsco 7588 for the 1500
Atsco 7587 for the 2500

Rock Auto has good pictures :D They appear to be identical and I think it's worth a shot! I realize that they may be different ratios or one may be fixed ratio vs. variable ratio. Shouldn't be a problem though.


If anybody else has some input on the situation, I'm all ears!
 
they have different ratios 12.7:1 in 4wd vs 14:1 in 2wd for '05 boxes '07 2500 hd has 24:1 all the '99 models ive found are 14:1
 
So....other than the small variance in ratios, they should interchange? The 2500 boxes look just about like an old Chevy Saginaw box, just has the mounting locations on the opposite side of the box since it's inside the frame. My goal is ease of adding hydro assist. The 1500 box looks like it'd be a royal pain to find out where to drill and tap.
 
Tappedsteeringbox002.jpg

572264d1295663520-tapping-borgeson-box-etc-borgeson-tapped-side.jpg

572262d1295664712-tapping-borgeson-box-etc-borgeson-tapped-1-npk.jpg
 
My intent is to go to the 2500 box, I'll post a pic of a 1500 box to show where the front part around the input shaft bolts on. Makes it difficult to drill and tap. I don't have a 2500 box to rebuild, unfortunately.

What year was that box from?
 
The first pic is a 99 silverado, 2 and 3 are a late 90s dodge that is basically the same as a 2500HD with different mounting holes
 
So what would you suggest?
 
On my 98 Z-71, it has variable speed sensing steering [or whatever]. Couple years back, it started "growling" when making low speed turns. Seemed like it was more 1 way, but I don't recall, left or right. There are 2 sensors, & the 1 under the dash being the easiest, & cheapest, was changed. Seemed to solve that problem. Then maybe a year ago, mostly when towing, [weight transfer?] running highway speeds, sometimes I get a sudden oversteer, or to much pump pressure, on a slight left curve. I've gotten used to it & expect it, so not much of a problem. Supposedly, it's the other sensor!:shaking:
 
I don't think mine has that. The 6.0 that I swapped in had a pressure switch on the back of the PS pump though. My truck is a work truck package. No carpet, manual windows and locks, etc.
 
Going to be drilling/tapping my new steering box soon. Planning to do it like the pictures. I found the threads they came from and read as much as I could. Seems just as easy as the older Saginaw boxes.

Not I just need to decide what assist ram to use with my setup. I have an Agri Supply 2x8 on my K30, but it seems a little slow. Any suggestions?
 
Well, now with a new steerong box, pump, and pressure line....I'm a little baffled. I have no bubbles, fluid doesn't foam, but sitting still, I have no steering. The pump doesn't make any noise, but the whole system gets pretty damn toasty.

Ideas? I'm guessing there must still be air in it, but I can't get it out. I've had it off the ground and probably turned the wheel back and forth 100 times.
 
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