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Hello everyone, How does a person check to find out if the steering geometry is correct on a pickup; I believe I’m having bumpsteer. Thx

What modifications have been made, if any? Bump steer is usually caused by lowering the vehicle, and/or installing a IFS system without doing some homework first. Assuming you still have a straight front axle, check to see if the drag link between the steering gear and the left front wheel is parallel to the ground. If it's not, the vehicle will dart side to side every time you hit a bump.
Jerry

One major cause of bump steer can be caused by the drag link not being parallel to the ground and frame.
A pic of a drag link thats way out of parallel, Pic

It looks like Tennessee has it.

Ed

Hello, The mods that I have made are; I installed a power steering box from a toyoto & had the arm cut ( that connects to the gearbox) & removed 4 leafs from the springs; Also I’m running bias ply tires. I had the front end aligned but it didn’t make any difference . I will ck the paralel to the ground. Thx

Like the lady who had the ugly baby- - - - -you grew it, so try to learn to love it. Tinkering with good engineering without understanding the basic principles usually has unintended consequences.
Jerry

How much caster angle do you have? I would think you need at least 4 degrees or more if the front end is lowered.

Jerry, thats why I consult you experts; I figure you all have been there & done that; It’s called experience. 😜. Anyway I measured the draglink & the back end is 2” lower than the front end. I ha d the front end aligned but I don’t know what the caster degree is.

2 inches might as well be 2 feet in terms of bump steer.

How is that fixed I measure mine after reading this mine was not modified that I know of it’s 1” lower in the back, 🎩

Do you ever experience bump steer?

If the drag link is lower at the steering gear end on a truck that has not had the axle modified, the springs are worn out. This allows the steering arm end of the drag link to sit higher than the end of the Pitman arm. When a bump is encountered, the front end of the drag link goes even higher and the increased angle pulls the steering arm away from the ""straight ahead" position of the wheels. Since both wheels are connected by the tie rod, the wheels swing side to side as the springs flex.

All vehicles will have a little bit of bump steer. The idea is to minimize its effect on the wheels by starting out with the drag link level. The further out of level the drag link is with the vehicle at rest, the more pronounced the steering input will be. The only way I can think of to minimize bump steer on a lowered vehicle would be to raise the steering gear on the frame the same amount the vehicle is lowered, causing the drag link to be level again.
Jerry

Haven’t driven this truck yet I’m still building it
it came to me as a non-runner just thought I’d check it since you guys were talking about it 🎩

I have around 30 vehicles in my storage yard and probably half of them were given to me for hauling them off or sold for just what a new major part ( engine, trans, etc) had cost the owner. A large number of these were considered "death traps" with 90% of this problem being botched up suspension/steering. If the previous owners had just done a minimum of research then they would be cruising with a smile on their face instead of a bitter taste in their mouth. WRITE THIS DOWN: Caster, Camber, Toe In, Anti Dive angle, and Ackerman Geometry. It's easy reading and a snap to understand so keep the welders/torches/tools locked up till you lay the book down and your "Baby" will provide you with a lot of pleasure. We build them from chalk marks on the floor to finished rides and the minute they are done with all the bolts tight and cotter pins in place I'd drive them wide open and take my hands off the steering wheel---it really is NOT rocket science.

Now Evan- - - - -everybody knows that some mouth-breather with a torch, a sledgehammer, a welder and a Fatman IFS kit is smarter than all the engineers who spend millions of dollars on research and development before the factory starts producing suspension systems- - - - -just ask 'em!
Jerry

Jerry,
You must have jumped the fence at my storage yard and studied some of the "handles terrible" abandoned projects. Can't figure out why this Nova clip on a 50 Ford pickup was troublesome, especially after they spent a WHOLE weekend with the above mentioned tools.

[img]https://s9.postimg.cc/g8kzsqhmj/IMG_4136.jpg[/img]
[img]https://s9.postimg.cc/m9iopvh4b/IMG_4137_1.jpg[/img]

Wow! Some real fine welding there!
Reminds me of the time I retrieved a jon boat that had capsized with 4 guys aboard (someone else plucked the guys out of the drink). Once I got it to shore I discovered it had previously broken in two and had been welded back together. Said to no one in particular "Dang, I should have just let the inlet have that piece of junk".