Steering "Wander" at highway speeds

[Jzbochat]

I have a 1972 f100 2wd. I have replaced the old gear box with a rebuild, original Ford gearbox. I have also replaced the drag link, tie rod ends, kingpins, I-Beam bushings, radius arm bushings, both front coil springs, as well as all four shocks, yet I still "float" at highway speeds. I am constantly fighting to stay in my own lane! I am looking into getting a rear sway bar off a dentside to help with body roll, and maybe even a steering stabilizer? I am also going to swap the 3.25 posi to a 3.50 Trac Loc to get both tires to do their job properly. I've tried everything to make this truck stable but nothing seems to keep it "planted" to the road. At this point I'm almost tempted to just put a straight axle in the place of the Twin I-Beam. Any suggestions? Thanks

[CH3NO2]

Check your toe mesurement. It should be toed out 1/16 to an 1/8 of an inch. 0 toe or toed in and it will wander like hell.

[t-waits]

Cant remember what its called but there is a rubber like washer that connects the steering column to the steering box. If it is worn it too will cause wandering. You can see it by standing outside the truck looking under the hood at the box while moving the steering wheel, if worn you will see the slack pretty easily.

[390FE1972]

The part mentioned above is the steering coupler or rag joint, it is usually one of the first things you want to check if you are having steering issues.

Regards!

[markguiver]

Check the rag joint (rubber doughnut thingy ) and have an alignment done at a shop that knows what these old trucks need. If you've only had this truck a short while, and are expecting it to drive/handle like the newer trucks, it probably never will. One of the handling issues is due to the twin I beam suspension design. While driving at highway speeds, the suspension loads and unloads at every bump and dip in the road surface. As the suspension unloads the I beams move up at the pivot point causing the outer edge at the tire to drop, pulling the inside of the tire toward the center of the truck. This causes a slight pull (wander) to the right or left. A proper alignment can eliminate most of the symptoms, and will give you a good ride. If you were to lift the front of the truck and put jackstands under the frame and allow the front suspension to droop you will see that the bottom of the tire is angled in and the top is angled out. The I beams swing on a fixed arc and the tires follow that arc too. The twin I beams are not as forgiving as A arms, but they're a lot tougher. Simple right?
Mark.

[Ohiotinkerer]

Every piece in the front of my '68 except the power steering box has been replaced at almost the same time and on my 1500 mile round trip i took to Tennessee and I still had times - especially on the interstate - where it would decide it didn't like the lane it was in. It was worse before I did an entire rebuild and I did change back to a stock size tire on the front - 31/10.5 to a 235/75-15 - which helped after the rebuild but it's unfortunately something that is common to the twin I beam of that era......I've owned later model F series and Rangers that didn't do it and don't understand what the difference is.......

And DEFINITELY get a sway bar......after a couple of sharp on ramps mine will be getting them front and rear......forgot how much roll the old bumps had that didn't get built with them.......

[Jzbochat]

Thanks for the input guys! I will definitely be getting a Rear sway bar and I’ll have my front end aligned. I’ve noticed one of my front tires is turned quite significantly while the other remains straight!

[Ohiotinkerer]

If you're looking to buy new sway bars Addco makes them for both front and rear........the front is Addco 113 and the rear is Addco 340.......both of them are 1" diameter. .....

[Modified_66_F100]

probably the same issues - digging deeper

Background - I have `66 F100 2WD with all new/rebuilt suspension. I'm running 73'ish disk brake spindles, power steering box and pitman.
I have had four steering boxes and three different style of pumps, the I-beams twisted and arc'ed to get proper caster and camber. Running stock hight with Monroe Monro-Matic shocks and 6-cyl springs due to all alum V8. No sway bar. My goal is stock appearing and comfortable ride. I have way too much power limited by scary wander at most all speeds. I have driven old cars and trucks and have well tuned reflexes to cover for the bump and roll steer "designed into" the stock geometry.

I've got to improve this and feel I'm getting closer.

Current Plan - The box has springs in it that flex as you turn to send more fluid pressure to boost one side of the piston more than the other. I believe these are much too weak causing over boost. I have tried reducing the pressure by shimming the pump regulator and used an external regulator but that only reduces the total boost available when parking (full spring deflection). If I can find, or make, stiffer springs then it they will send less or no oil during cruise.

I am also, reluctantly, considering stiffing the ride with heavier shocks, a steering dampener and/or swaybar, but this won't fix the crazy light steering feel.
To reduce bump and root steer I am considering a completely different tie rod system common in the off road world or designing a modern long travel double A-Arm system but that will have to wait for money and time. I don't want a car suspension; my house is off road.

Please correct me if I am wrong or off base as fixing this is so much more important than my pride.

[Modified_66_F100]

probably the same issues - digging deeper

Background - I have `66 F100 2WD with all new/rebuilt suspension. I'm running 73'ish disk brake spindles, power steering box and pitman.
I have had four steering boxes and three different style of pumps, the I-beams twisted and arc'ed to get proper caster and camber. Running stock hight with Monroe Monro-Matic shocks and 6-cyl springs due to all alum V8. No sway bar. My goal is stock appearing and comfortable ride. I have way too much power limited by scary wander at most all speeds. I have driven old cars and trucks and have well tuned reflexes to cover for the bump and roll steer "designed into" the stock geometry.

I've got to improve this and feel I'm getting closer.

Current Plan - The box has springs in it that flex as you turn to send more fluid pressure to boost one side of the piston more than the other. I believe these are much too weak causing over boost. I have tried reducing the pressure by shimming the pump regulator and used an external regulator but that only reduces the total boost available when parking (full spring deflection). If I can find, or make, stiffer springs then it they will send less or no oil during cruise.

I am also, reluctantly, considering stiffing the ride with heavier shocks, a steering dampener and/or swaybar, but this won't fix the crazy light steering feel.
To reduce bump and root steer I am considering a completely different tie rod system common in the off road world or designing a modern long travel double A-Arm system but that will have to wait for money and time. I don't want a car suspension; my house is off road.

Please correct me if I am wrong or off base as fixing this is so much more important than my pride.

[Modified_66_F100]

It turns out many shops actually don't have the tools to cold bend the forged I-Beams, as needed to set the caster. I am considering making a set of the arms that hook over the beams and connect to the hydraulic ram. I've paid for three alignments from shops claiming to have the tool and a forth to find I got shined on and have very little caster - still.