I am upgrading my truck from the original power assist steering to the late 70's integral power steering system. Need input from those who know... HIO Silver - you the man bud! Anyone else done this?

I need to install this gearbox with proper positioning and clearances. I have a pretty good idea as to where it is going but I really would appreciate all the extra eyes on this I can get so I dont miss something. Lets get started.

Here it is laying on the left frame rail (frame is leaning against a wall) in close approximation as to where it needs to be...



I am positioning this based on this template which I made from the donor truck (78/79 Bronco/F150). The biggest difference I am seeing on the outside of the frame is the donor truck didn't have the same curve as my 75 F100; hence the flat 3/16" plate I will be sandwiching between the gearbox and the frame. At first glance it appears I will need to bring the gearbox straight down by about 1/4" to clear the pitman arm from the frame. It still clears the top of the frame and the angle is almost exactly the same.









This looks closer than it is (1/4" of clearance) but with the plate installed the clearance will be even greater.



My measurements indicate I will need a minimum of 3/4" clearance above the end of the pitman arm for the tie rod end... I have 2" of clearance here so its good. It appears this will almost perfectly align the gearbox side of the tie rod with the center of the cross member... Is this appropriate?



Here is the plate I will be installing... Also this photo demonstrates the need for the plate... I don't want to install the gearbox on a curve.

 

After thoughts...

I probably should temp install the other frame mounts such as the engine perch, track bar mount, spring mount, etc... just to be sure I am accounting for everything possible. I imagine this may leave me trimming the inner fender at some point... This is fine. Hopefully it doesn't interfere with the engine or anything. I really have no way of clearancing that. The closest component would be the power steering pump. If it does I may have to go with a saginaw pump which would give more clearance so this wouldn't be catastrophic... Just prefer to not spend the extra dollars.

I am probably over thinking a potential issue with the geometry... Basically, how exact does the position of the gearbox need to be to ensure the steering all works properly? The more I think about it the more convinced I am that my primary concern should be with the clearances as any issues with the geometry can be adjusted out. Obviously I can't have binding on the rod ends or anything but I would have to go an excessively long way off (like 5 or more inches) before this happens.

My end game is to have the frame sand blasted and painted. I don't want to have to modify after new paint is applied. That said am I close enough here or should I do something like reinstall the front axles to get a good ops check out of it? Even with this I can't account for the weight of the rest of the truck so this might be a waste of time.

Hmmmm... Thinking marking would have been good to do before tearing down but this wasn't in the cards at that time. Hindsight...

I need to just stick it on there as its probably fine and just deal with any adjustments later on. Any thoughts on this?

 

I have a 75 4x4 and did exactly what you are doing. I drilled mine a little further towards the front of the vehicle. I think I used the oblong hole for the front bolt from the look of it, but I don't recall for sure. I think your location might hit the track bar bracket or will be right up against it because mine is pretty close. I didn't use a plate on mine and it is not causing any issues so far. There were no gaps with the way the gear actually sits against the frame. I drilled an access hole in the inside boxed section of the frame to get the nuts installed on the two rear bolts rather than risk crushing the boxed section with bolts going all the way through. The metal on the inside is pretty thin- too thin to take that much torque IMO. The forward bolt, I was able to get the nut on it through an existing hole in the cross member. All of the steering linkage went together perfectly and works great.


As for the inner fender, I don't have the rubber part on mine that covers the gap to the frame, so I was able to just bend the bottom edge upwards with a pair of vice grips to clear the gear.

 

I have a 75 F100 4x4 and did the same conversion. I used one of the original holes for the old gearbox. I believe the top one. So its mounted closer to the radiator. I had to notch out the radiator support a little and the grease zert would hit on the bottom of the frame. I just put a plug in the hole till I need to grease it. I suppose I could put one of those needle grease fitting in hole. I did mine in 2005 and its still working great. Going to try to put up a pic that I took today.

 

 

Didn't use the spacer piece on the top. Didn't have to cut the inner fender and I am running a 90's power steering pump. No clearance problems

 

My steering box was rebuilt so its steers the other way by benchworksteering in Arizona

 

Thanks... I was assuming you went with the 4x4x2 setup.

 

I am not sure what you mean by the 4X4X2 setup. I used the opposite steering gearbox and the manual drag link, all the other parts are stock.
I also have the borgenson steering shaft setup so it is adjustable.

 

dirtracer I don't see a track bar?

 

It's there in the stock location. My gearbox is mounted in the same location as the original one. Not way back like the other pics

 

4x4x2 - it's a term used to refer to the steering system you have. Your box was originally setup like mine (4x4) but they put a 4x2 reverse worm gear on it. Hence 4x4x2. Very common on the original Bronco.

 

4x4x2 how to:

https://www.ford-trucks.com/forums/1144182-steering-box-conversion-pics.html

 

I'm looking to do the same thing for my truck. I have a 1975 f100 4x4 with a 6 inch lift and 35s. I wanna take the front axle out of my 79 bronco bwcause it has disk brakes and the good power steering. If someone could tell me the challenges and more in depth about how to mount the steering box. That's my main concern is how to mount that. Any help would be appreciated.

 

Hey Nick. Welcome!
I haven't done it myself, but seems like it's pretty well laid out in the previous discussion here. Well, laid out other than it sounds like the three different trucks got three slightly different mounting schemes!
But that makes it sound like you're not locked into just one way of doing it "right" and nothing else will do. Seems there is some leeway.

The others said they did not use any additional plating, but did not say (I don't think) that they used anything behind the box to keep the mounting point on a flat plane. you don't want the gear box being held off under some parts of the box. Sitting flush against the frame would be desirable I do believe.
But in lieu of a full welded on plate, some solid spacers to fill any gaps would probably be acceptable. The plate was a good idea though. If you're going to be running your truck hard, reinforcing the frame in the area around a very powerful hydraulic system seems prudent.

Good luck. Hopefully the guys that did it already will chime in with their experiences. Especially those that did them awhile back and have had the chance to spend some time with it.

Paul