strange steering

i just put in a rough country 4" lift kit on my 86 1/2 ton suburban with front springs and rear blocks the kit came with a steering arm also the steering wheel goes back and forth about 3-4 inches when i go over dipps in the road nothing real eratic but its their like something is pulling the steering or axle or something i cant figure it out the tie rods and steering link are new alignment is new i do still have the stock tire and rims on it kinda waiting to see if the steering is ok or normal am i being to picky or perinoid any ideas ?  

The little short draglink that goes from your pitman arm on the steering box to the steering arm on top of the knuckle shoud be absolutely flat. If it's not flat, you'll have bump-steer. The less it is flat, the more dramatic the bump-steer will be.

Now some people confuse the names between a pitman arm and a steering arm. Did you replace the arm on the steering box or the arm on the knuckle? And if the draglink is not flat after replacing one of the arms, you should replace the other arm to make the draglink flat. That will fix your bump-steer problem.  

its pretty darn flat do you now witch way effects the steering  slanted up or down in the rear of the steering arm  

If it's not absolutely flat it will affect your steering when the suspension cycles up and down. The more that the draglink is angled in either direction, the worse the bump-steer will be.

If the draglink is higher at the knuckle end, that would have a greater effect on your steering when you hit a bump. The draglink travels in an arc and that causes an "effective working length" change. This length change increases at a faster rate when moving away from a flat position, slower when moving towards a flat position.

You want it to be deadass flat!  

i'm afraid to ask how you adjust it 1/2 inch or so  

Which arm have you already replaced?

There are several ways to adjust the draglink angle.

Pitman arms come in different drop offsets like 1.5", 2", 2.5" and the steering arms also come in different offsets. Some steering arms are bent to create the offset, and some have a thicker mounting base to them.

So, you just have to match the two arms with each other to make the draglink flat.  

i put in a 4 inch lift and put in the steering arm that came with the kit  

Hmm... might be difficult to get a 1/2 drop pitman arm.

Which end of the draglink is higher, the knuckle end or the steering box end?  

boy its hard to tell it looks pretty straight if any thing maybe the steering arm end a little i've tryed going to a parking lot to be fairly level and the steering arm end may be at the most 1/4 to 1/2 higher  

checked it on the alignment rack again today the steering arm end is little lower than the pitman arm end  

well the latest is rough country read a post i wrote and told me to call them and i did and now they are going to send me a updated draglink so we will see hope it works.  

well i put in the new draglink and pretty much the same way of steering the new drag link is so off set that it hits the steering arm when the truck is lowered to the ground so you have to turn the offset side ways and then the ends are not straight rough country said turn it any way until it clears the steering arm the idea seems good but i think the off set is to much still waiting on rough country.  

u prolly got a loose steering knuckle  
*** a japscrap buy a chevy