Worn king pins=steering wander?

when you install kin pins you should take a break hone and hone the bushings to fit the kinpin insure that the kin pin slides easily threw the bushings without binding. it is possible this step was not done right.

i replaced kingpins on a izuzu npr not too long ago because the king pins were binding. the wheel was defiantly not centering itself. after dropping the steering arms and tie rods off i could not turn the wheel ends by hand.

 

I believe cranking down on the steering box adjustment screw is causing the problem here..[/QUOTE]
Not sure if you are referring to mine or rollin coals, but I think you are right in my case. After further scrutiny, I have established 2 things. King pins (and bushings) worn out. My play in the steering is 95% from the box itself, even though it's not that old. The sector shaft adjuster is all the way in, and when I start backing it out, the play gets worse. So I am going to do 2 things, get a new box installed, as well as a king pin kit. I will come back with results once I get those done. I don't believe the worn out king pins are affecting the steering that much, they just need to be done anyway.

 

Replacing king pins will change toe in

 

I can answer that, he's already dealt with that. His caster was ok, but had it adjusted to a very high number and it didn't make a difference.

 

Guys, not to jack LoMax's thread but I loosened the adjustment on my steering box. It was a little tight from the factory imo. I asked the last suspension shop about loosening it more and they said no way, leave it slone, it was good.

Heavyd, you're probably right. They must have thought the same thing because they re-did the right side king pins. But still the same problem. The second shop down the road never mentioned what you did as a possible cause.

 

So RC let me see if I have this right: we both have trucks that aren't behaving with their steering? We both have trucks that have a problem in the steering box? I can visually see that I have play happening in the box, no question. Since mine won't adjust, it's coming off pronto. Constantly having to fight steering especially on our crappy highways up here is getting old. A guy gets tired enough from dealing with heavy in a hurry traffic all day without fighting the truck too. You have any plans to do anything with yours? BTW is yours a TRW also.

 

New king pins were installed too tight...

 

Yeah TRW. You darn near have to remove the steering box on mine to adjust it. I've reached the conclusion the only thing that could possibly fix mine is for the king pins to be rebushed. Everything else has been replaced, adjusted, or checks good - really everything is practically new.

The shop that did them re-did the right side but not the left. They didn't charge me for that. I had another shop install new leaf springs and try to explain to me what the issue was. Never did get an answer from them. My feeling from them was they didn't want to bad mouth the other shop but it was shoddy work. Both have been in the same business not far from each other for many decades and respected by drivers around here as putting out quality work.

I believe the second shop didn't want to tell me it needed re-bushing as they knew I had already spent several thousands on the front end already. I wish they had. I would have paid them to do it right then and there. As it is now I just drive it and not bothering with another 185 mile round trip up there to have it done. Really fed up with it. I figure it will either wear in or not.

If I ever need king pins done on another truck in the future i'm really suspicious of anyone out there doing it and doing it right.

 

The sector shaft adjustment being talked about is not what I meant. In the hydraulic control sections of these units are valves to change fluid directional flow and pressure. If one of them is leaking by it can cause pull one way, the other, or in either direction.
If you put a new or reman unit on it should not require adjustment.
Years ago a company I worked for installed hydraulic P/S on 4200's. The boxes were not TRW or Rose but factory remans. One of them did squirrely stuff like that, did the volume psi tests, adjustments and outlined by the mfg and they replaced it.
Look on line at Steering Diagnostics Service Manual. I found it searching TRW steering, hope that helps!

 

Update. Finally got my steering issue fixed! To keep it short and sweet, it was 2 things. Steering box, and king pins. I thought the box was good, but I wasn't looking at it close enough. I got the box replaced, and steering was better, but still had wander. King pins finished the job. Steers almost like a new truck, better than it ever has in the 4 years since I bought it. Here is a tip. When you are trying to find a problem, whether electrical, or mechanical, doesn't matter, slow down and put yourself into slow motion, and think! And be critically observant. It seems that a lot of us truckers are often under pressure from different directions, and it's easy to get in a hurry because we need to get our problem resolved and get back on the road. We don't always take enough time in looking for, or trying to fix problems. There was a fellow recently with a bizarre problem in that he couldn't get his gauges in the dash to work (J.L.R.). It took him a long time, but he finally found the problem at the end, with careful, critical observation, found a wire that "didn't feel right", because it was coming apart inside the insulation, would test ok for continuity, but wouldn't carry a load. He found it where the professional shops couldn't. Hats off to him! Anyway to answer my very original posted question, Yes! Worn king pins can cause steering wander, especially if driven by a worn, or out of adjustment box.