Even though this is my first post i have been searching on here for weeks and have tried just about everthing to fix my problem. Here is what i have.
A couple months ago bought a 86 K5, steering was loose when i test drove but i figured it would be, didn't notice any bump steer. Trailered it home. When i drove it when i got home on backroads i noticed the bump steer and it wandering on the road. it's got rough country springs on the front and blocks on the rear and 33 x 12.50 tires. i'm pretty sure its a 2" lift.Here is what i have done first, change the shocks, steering stablizer, lowered sway bar and transfer case (rough country suggested), new bushings on sway bar and new steering box. After all it seemed to help alot. before i changed the steering box it would wander on the road when i would hit a bump but the steering wheel would not move. After i changed the box the wandering seemed better but when i would hit a bump the steering wheel jerks. So, today i went to get the front end aligned, i knew it needed it. They got it aligned with caster and camber kit, replaced tire rod ends and all ball joints and bearings. I told them might as well while they had it, not that everything was wore completely out. Got it back today front end is align great everything should be good but it's not. I still have a little bump steer but not as bad and the steering box seems a little tight. This is where i need help I see where everyone says with a 4" or 6" lift use a drop pitman arm to level the drag link. Mine is actually going down hill toward the pitman arm rubbing the steering arm when i brake. I don't think i have a drop pitman arm, it's pretty much level. i'm wandering if someone has put a raised steering arm or the front springs are bad. The truck sits level and the pitman arm clears the steeriing arm by about 1/4 inch. I haven't drove it but a few miles as far as the steering box goes, i'm hoping it still has air in it. Running out of things to replace and just need some help before i spend anymore money trying to figure this out. Does anyone know what the height of the stock steering arm should be?

 

Here are some pics

 

Man, you need a new pitman arm.

 

Reading your troubleshooting brought back a lot of nightmares. When you replaced your steering box did you CLOSELY examine the frame where it mounts? GM 4x4 frames are well known for cracking in that area due to stress. If you find cracks they can be welded. There are a few kits that assist in repair of the frame and the strengthening of that portion of the frame as well that you should look into.
One other problem you may look into is the torque of the spring-to-axle bolts (4 per side). If not torqued properly the axle will slip inside the spring perch giving rise to the changing of the steering angle. This can be noticed best if a helper sits in the drivers seat with the motor running and turns the steering wheel as you watch the axle tube where U-bolts are nearest at the spring perch. If they are not torqued properly you will notice movement where there should not be any. Even 1/16" is too much.

Either condition will get worse. It sounds like you are on the right track.
Good luck with your repair and safe journeys.

 

Thanks for the replys. My frame is not cracked, looked it over real good when I changed steering box. I'll check and see about the axle bolts tonight. I'm planning on keeping this truck for as long as I live so I don't mind changing out old parts for new, but i'm just running out of parts to replace.

 

What about tie rod ends? What kind Whatof tie rods did the alignment shop replace them with. Selling parts over the years I've seen the cheap economy units go bad very very quickly with the use of a larger tire. Now granted a 33x12.50 isn't huge, those stocks ends were made for a 28inch pizza cutter. Also what is the condition of the drag link bar? Is it bent, show any places where maybe it was heated and bent back in shape after damaged? This could cause a weak area in your steering

 

Not sure on the quality of tire rod ends, but the guy at the tire shop knows that I want it done right and I have known him for about twenty years. I don't think its them because it done it before and after they were replaced. I've only drove it about 5 or 10 miles since they have been replaced. As far as the drag link goes it's straight, I really don't understand why it is angled downward. With a 2" lift it should be angled upward if any at all i would think. After they aligned the front end the drag link is sitting on the steering arm. I noticed a noise after i got it back when i hit the brakes. Even when i'm going slow in a parking lot I can tap the brakes and it does it, i'm thinking its the drag link tapping that steering arm when it noses down but I have not confirmed that yet. Did you check out the pics?

 

The component you need to chance is the steering arm. You have a raised steering arm that is designed for 4-6" lifts. The drag link needs to be parallel to the ground. If you have an option you want it to slope up towards the pitman arm instead of how it is right now.

Secondly a lot of the problems that you are describing are a design flaw in the push pull steering of the period.

Because of the short drag link as the suspension articulates the relative relationship of the axle to frame distance changes dramatically. This is especially noticeable in off road driving. If you ever put your drivers wheel in a hole the steering wheel will turn to the right and you'll loose the ability to turn left. Yea, that's a serious problem.

The cure for this design problem is cross over steering. Many vehicles use different forms of it and you can spend some pretty decent money to install it as there are a multitude of components necessary.

To help out right now get a stock steering arm, or go to a 4" spring... 2" springs are kind of a tweener when it comes to modified steering components.

 

Thanks 70-K5 for the info, that's kind of what I thought the problem might be since it looked a little taller compare to pics i've seen.

 

Does anyone know where I can get a stock steering arm?