The Stovebolt Site Forums The Shop Area General Truck Talk Bump Steer

Anybody else have this problem while cruzin down the road.

True bump steer is a phenomenon caused by improper geometry between the pitman arm, drag link and steering arm.

This is usually a result of an poor attempt to lower the truck, or some other ill conceived steering change.

Poor handling on rough or bumpy roads might be due to loose steering or front end components, bad shocks or extremely wide tires, but I don't think this is actually bump steer.


Stuart

I had put on a power steering kit onto my straight axle. Which the kit works great but I found that after installing the kit I had bump steer happening. On closer inspection. I had installed the drag link with one ball joint on one end facing up and on the other end facing down. Which cuased the the drag link to be at steep angle from the pitman arm to the steering arm. So what I'm guessing is that when I hit bumps and the suspension goes up and down It changes the angle of the drag link cuasing bump steer

I had the same problem, and the same setup as you describe with your drag link. Whenever I would hit a bump, the truck would jerk to the left and then back to the right as the suspension compressed/ extended. The steering wheel wouldn't be affected by the bump steer. From what I could understand from all of the techincal info on the internet, The drag link must be paralel to the ground, and a longer drag link has less bump steer than a short drag link. I had the drag link adjusted to be much closer to level and wow! what a difference! It took out at least 80% of the bump steer. It takes a pretty big bump to feel any jerking at all now. Cornering on the highway is better now too; bump steer tries to steer you to the outside of a corner as the truck leans and compresses the suspension on one side.
I also installed a front sway bar to help on the cornering.
Hope this helps.

when I hit a good bump in mine you feel it but the truck goes true.........

one of my old mustangs use to have the real bump steer if it was out alined.......

Good post. I am contimplating putting it on my 55-2. I,ve been wondering about this. Any more info will be apreciated.

I use the original master/slave PS system. One end of slave cylinder is mounted on the driver's end of the solid axle, other end attached to cross steering rod - moves up and down with axle. No bump-steer.

Bump steer can be a problem on solid axle vehicles. The wheels don't articulate inividually as they do on an ifs, so the forces often are tramsferred to the opposite wheel. Power steering does help to aleiviate/mask the problem, especially the slave cylinder type that has a ram directly on the tie rod. Another fix is to add a steering stabilizer. I opted to do that on mine. Moog makes a good one that will fit pre-'59 solid axle trucks. It's a Trail Boss damper, part # SSD12. You might have to do a little fabrication to make it fit perfectly, the mounting hardware is intended for a 4x4 axle. The mounting is similar to the slave cylinder for the factory type power steering.

Longbox, could you post a few pictures of how you installed the stabilizer on your truck? I might want to try one of those some time.

I've placed some pix on my webshots page. I still ain't got that picture linking figgerd out yet. The mounting to the axle is a 1/4" stainless plate, the U-bolts that come with the kit do not fit the axle very well. The bolts are grade-8 3/8", 4" length as I recall. The other end is the standard parts that come with the kit. The U-bolts on that end will have to be loosened to adjust toe.

Robin58: Leaf springs are supposed to be flat? I was getting ready to replace mine because the were flat from the enging weight and I figured they were worn out.

I have used those steering stabilizers & they work good with power steering but I treid one on my 55-2 without PS & it was horrible. I pulled it off the next day. I will put it back on when I get the power strg. installed.