1972 Ford F100 4×4 Power Steering Upgrade

  • Upgraded 1972 Ford F100 Power steering

    Year: 1972

  • Make: Ford
  • Model: F100
  • Category: Steering and Suspension

Tools Needed

  • Wrenches
  • a drill and bit
  • some drilling oil

Parts Needed

  • 1979 F-150 4×4 steering box
  • 1981 F-150 4×2 steering box
  • 1979 F-150 4×4 steering box rebuild kit

How to Get it Done

I’ll start this post with a picture of my current steering box setup since I think it is the best overview picture you can probably find on the net due to having  the Front fenders removed.

I started with a tutorial found at Fordification.com which gets most of the way there, but the author did not complete the discussion so I am writing a complete How to Guide based on what I did with the help of Fordification.com

The Modification I chose was to use a 1979 F-150 steering box and swap the worm gear to a reverse thread for the purpose of mounting in the same location as the existing manual steering gear. Without this modification the truck would go right when you turn left.

Making Two Gears From One

The process of swapping the gears is actually quite easy. here are the steps.

Step 1

Remove the Pitman Arm on both units. This can usually be done with a hammer and a pitman arm puller. this is probably the most difficult step in the process. If you have a really hard time just pay a machine shop to remove it for you. Chances are it will cost 15 bucks or so.

while there is tension on the pitman arm from the puller hit the side of the pitman arm with the hammer on the axis. this should normally break it free.

Step 2

Remove the Sector Shaft from both units, you will be reusing the 1979 F-150 one.

To remove the sector shaft all that is necessary is to  remove the bolts connecting it to the gear and pull it out. Pay attention to the orientation as it is pulled.

Step 3

Once the Sector Shaft is removed you can unbolt the worm gear rack and slide the whole assembly out. Do this for both units.

Step 4

Put the Worm Gear rack from the 1981 steering gear into the 1979 steering case and bolt it in place. I thought it was very convenient how interchangeable these two parts were.

step 5

reinstall the 1979  Sector shaft into the 1979 steering gear once the worm gear assembly from the 81 has been installed.

Step 6

reinstall the pitman arm. I was replacing my drag link with a new setup due to a power assist gear so I just bought some new moog tie rod ends and fabricated a drag link. More on that later.

Congratulations Your done!

Installing the Gear on the Truck

As you can see from the picture above the new power steering gear went in place of the old manual gear. I was able to use one of the existing threaded bolt holes which lined the center of the sector shaft approximately where the old manual gear one used to be. All I had to do is drill a couple of holes, buy some hardware and cut a chunk out of the radiator support to make room for the larger gear.

Making a new Steering Shaft

The new power steering gear will be quite a bit larger than the existing manual steering gear. Unfortunately, This means you will have to make a new steering shaft as your old one will be much too long. fortunately, flaming river makes everything you need to do this. As a bonus they will be much more shiny. The price on the Flaming River products is also quite cheaper than the Borgenson stuff. For the Ford truck it will be necessary to obtain two 3/4″-36 spline  to 3/4″-DD  U-Joints and an 18″ Double-D shaft to be cut down to appropriate size. I have posted an article for  fabricating a steering shaft with these components here.

3/4"-36-spline and 3/4" DD U-joint from Flaming River Industries

3/4"-36-spline and 3/4" DD U-joint from Flaming River Industries

Stainless Steel DD 18" shaft from Flaming River Industries

Stainless Steel DD 18" shaft from Flaming River Industries

Taking Care of Details

A power steering bracket and pump will need to be purchased for your engine. In my case , I had a 1978 460 from a grand marquis that already included the power steering pump So I didn’t need to handle this. I know this is done frequently and the parts are more than likely available at your local part store.

You will most likely need to get a new Pitman arm or fabricate a new drag link with appropriate Tie Rod ends. You’ll probably have to do this anyway if you are looking to lift your truck.


This was one of the more challenging problems I had to deal with due to all of the things that need to be changed. Chances are this will take a couple of weekends to gather parts and fabricate necessary Items.