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I want to put power steering on my '54 GMC 1-ton. I've debated how to approach it, and recenlty was looking at the parts used in the common 1/2-ton kit that uses a 70's to 80's pickup steering box.

Those kits include pieces to mount the box, a steering arm and a drag link. They require a steering box and pitman arm from donor vehicles.

I was thinking about copying the approach, but making my own parts. As I looked at a 1-ton beside a 1/2-ton I realized the bolt location for the steering arm looks the same on both the 1/2-ton and the 1-ton. I don't have a 3/4-ton so I can't compare one of those.

After staring a while I did some measuring and decided within the limits of what I can measure the bolt diameter and bolt centers are the same. These are the upper bolts that attach the backing plate to the spindle. It looks to me like the steering arm from the 1/2-ton kit will just bolt up on the 1-ton.

If that is the case then the steering box needs to be mounted to the 1-ton frame in the right location far enough forward that the drag link is the right length, and with the box centered to ensure the wheels point straight ahead at the right point.

So does this make sense? Think it will work? Have I missed something in my thinking?

The truck I want to modify is a '54 GMC 1-ton dually. However I plan to use a frame from under a '55 1st GMC 1-ton single wheel truck. I'll either swap the hubs or complete front axle. The 1/2-ton I measured is a '53 GMC. The 1-ton I measued is a '49 Chevy. To my knowledge none of the things that should matter are different between Chevy and GMC or year to year in the series.

Anyone know different? One concern I have is that most my assumptions are based on 1/2-ton trucks. My 1-tons may not be as similiar as I think.

One more thing worth noting. I am trying to maintain the 1-ton load rating. Simply swapping to a 1/2-ton axle does not support my purpose. And part of the idea here is to go straight-axle instead of IFS.

Thanks for any feedback or ideas!

Well Steve,
I did a P/S conversion on my 4400. I did it back before there were kits so everything I did was done with donor parts and home fabrication. I replaced the steering column too, which was the main reason for the upgrade, a V-8 install. Anyway, the way I saw it was, you need a mid 70's 4X4 steering box so the pitman sticks out perpendicular to the frame like the steering arm on the L/F spindle does. I made a connecting rod from the pitman to the spindle using the 48 parts on one side and the 4X4 parts on the other with a tierod adjustment collar in between. To connect to the column I just made a collapsable shaft from some truck with a wobble joint on each end. Borgenson can set you up now days,
Good luck with the build, it shouldn't be all that hard. Just a lot of trial and error stuff,
Scott

Steve,

I don't understand why the fore-aft location of the steering box is critical. With the steering box mounted in the most convenient place and centered (turn to turn) and the front wheels centered, the simple task is to make a drag link that reaches from steering arm to pitman arm.

Does this make sense?

Stuart

Stuart,
Yes, it makes sense and would work,

But to reduce bump steer you want the pitman arm to be near one or the other spring hangers.
Then the drag link swings approximately the same arc as the axle and 1/2 the spring do when going over a bump, and the steering stays reasonably constant and does not send you off in an unplanned direction.

Grigg

Steve I started in the direction you are talking even got as far as mounting the box (a mid 80s 4X4 box) http://rides.webshots.com/photo/2418906350096773078KeHMYq the problem I ran into may or may not affect your build, with the 10.00X22.5s on my truck I ran into clearance problems in a right hand turn the tire would hit the box, draglink, and pitman arm. I know this setup woks great for the smaller trucks in fact it was from a tech article in Classic Truck if you have a Saginaw box that bolts to the outside frame rail try bolting it as far forward as you can and with the front tires off the ground check for clearance if you have the room to turn right you have it made if not you may think about a scout box like Grigg and I have used.
If you wish you can have the box that didn’t work for me and I will see if I can find the tech article for ya.

Grant I'll be over!

Bump steer problems are ones I want to avoid. There is a drag link provided in the kit I've looked at. I'm imagining its length will put the box pretty close to the right place.

I'm getting myself ready to mock this up soon.

I've chosen a specific frame for this project, in part because the cab its under will never be repaired, while the frame is still quite straight, and otherwise perfect for my purpose. I'm swapping the rear axle anyway, and will swap the axle or hubs at the front as I do the disk conversion.

The finished truck as I see it today will have power steering, power disk brakes, a carburated 454 and a Turbo 475. The T 475 has a tailshaft emergency brake, which I like for this kind of project.

I'm still debating a 14-bolt rear with 3.73 gears against a Dana 80 with 4.11 gears. The Dana is a couple inches narrower, and closer measurement wise to the original rear. Its also stouter and will give more grunt. The 14-bolt probably means further on each gallon of gas.

This one is supposed to become my primary trailer puller.

steve, have you looked into using a toyota 4x4 power steering box from a pre 85' truck. they are the ones with a straight axle.they are easy to mount with simple Z shaped bracket.

I was just looking at one of those today, as some one stopped by with a Toyota truck and straight front axle.
My first thoughts are that it is about like the IH Scout box, but not quite as big or strong looking.
It also has the pitman arm pointing rearward and the Scout is forward, so the Toyota box would be mounted farther forward and then could interfere with tires.

My 48 2 ton with 9R22.5 tires and Scout box has plenty of room for the left front tire in a right turn.

Grigg