Truck wanders on road

[GlennWest]

My truck just doesn't want to go straight. Constantly correcting it. It's worse towing. I had king pins bushings replaced. Front end got sound condition report. 4 wheel alignment. This was shortly after I got truck but not many miles been put on it. I did tighten steering box. Think I need to tighten more?

[spindrift]

Was it going straight before the king pins were replaced?

[GlennWest]

No. After replaced still wandered. I drove a car a bummer shop aligned one time many years ago. He had put zeo caster in. Would not go straight down road either. Guy was supposed to be top quailefiefld that done truck. Just down the road from Livingston. Highly recommend

[GlennWest]

Also been tempted to install the Donovan valves in front air bag lines.

 

[spindrift]

Coukd also be tie rod ends, the tires themselves, broken spring(s), loose U-bolt...could be a few things, but it ain't good.

 

 

[dennisvr]

Have someone rock the steering wheel back and forth while you are under the truck (truck not running).  Check the drag link and tie rod ends for any play.  Then you could check the toe in by pulling a tape measure across the back of the tires and then check the measurement to the front of the tires.  Wider in the back means toe in.  I used to set them 0"to 1/16" toe in.  You can scribe the tire by jacking it up and while holding a sharp tool against the tire, (well anchored) spin the tire to scribe a line all the way around it.


 

[adept99]

Glenn;

Have you had the rig weighed wheel for wheel yet?  Failing that, a CAT scale would give you a good idea where the weight is concentrated. Have somebody follow you next time you move your rig and see if the trailer is dancing side to side. Too much weight behind the rear trailer axles will do that. Not enough weight on the king pin will also cause that. You may not even notice it while pulling, but the folks following sure will. Makes it tough to keep it in your lane...

Paul

 

[hone eagle]

What kind of hitch? Pin box.

My mor-ryde rubber cushions failed and towing i was all over, the play allowed the trailer to toss the back of the truck around a bit .

[GlennWest]

I have a hard pin box on camper. ET hitch on truck. Talked to a shop here in El Darado. He says over 20 years in truck service. Says likely toe off. He test drives the trucks and adjust if not right. Went there to see about getting it seviced and noticed his frontend equipment. Says he does trucks all the time. Going to give him a try. Nothing unusual about my setup. I retained original wheelbase when singling. 

[beemergary]

11 hours ago, dennisvr said:

Have someone rock the steering wheel back and forth while you are under the truck (truck not running).  Check the drag link and tie rod ends for any play.  Then you could check the toe in by pulling a tape measure across the back of the tires and then check the measurement to the front of the tires.  Wider in the back means toe in.  I used to set them 0"to 1/16" toe in.  You can scribe the tire by jacking it up and while holding a sharp tool against the tire, (well anchored) spin the tire to scribe a line all the way around it.


 

Good advise. Been doing my own front end alignments for years.

[Lance A Lott]

One of the track bars on the rear axle was loose when I got my truck and had been for some time you could feel the axle  move, it wondered all over at faster speeds. My brand new freightliner school bus has wondered from day one, not a lot but just feels goose.

[Ronbo]

I had my truck aligned by Strouhal south of Houston right after I got it. I put new front tires on and noticed cupping on rt front. Also steering shimmy at 55. When I replaced kingpins I removed cross tube and tie rods. I could mutate break the tie rod ends loose for anything. I replaced them all. I don’t believe strouhal did anything to my truck. I drives so much better now. 

[dennisvr]

Also if you ever want to check the rear axle for alignment.  Get one of those levels with a laser beam on the end and put it against the sidewall of the rear tire pointing the laser to the front axle and put the end of a tape measure on the front hub cap and measure the beam from the hub cap and the go to the other side and do the same.  
What I do is move the truck forward about 20' and roll to a stop without using the brakes.  Reason being there is movement in the trailing arms and the axles will move a little and it will be preloaded if you use the service brakes and then set the maxi's.
You can adjust the rear axles if they are out of alignment, but that will take a lot more typing to explain, so this is enough for now.

[GlennWest]

When I had the  king pins and alignment done just after I got truck, he adjusted the rear arms. Shims in one side. Stated not off bad though. Got a Lazer level. Hadn't considered that. Thanks.

[dennisvr]

4 hours ago, GlennWest said:

When I had the  king pins and alignment done just after I got truck, he adjusted the rear arms. Shims in one side. Stated not off bad though. Got a Lazer level. Hadn't considered that. Thanks.

Don't be alarmed if you find them out a little.  As I said there will be some movement in the rear suspension and with the distance between the two axles.  Many times on a tandem axle I would find each axle pointing in different directions.

[Lance A Lott]

When I pulled my truck apart to single the front frame bracket for the cross arm was worn in about 1/4" deep and about 1" long and the bolts were about 1/4" loose. They had obviously been loose a long time. My father put a air suspension on his 3/4 ton truck after about 5 years it started to feel loose. We looked everywhere but could not find anything loose. Only after removing the track bar were we able to feel looseness in the pan hard joint. The truck never had tire problems or alignment issue it was more of a sloshing issue, my mother and wife could not feel it, it just felt different than it used to. Good luck some of these things are very hard to track down.

[GlennWest]

I'll check that. Thanks. Will have to wait till this 10 day shutdown ends though. I should have 2-3 weeks off then.

 

[Steve from SoCal]

I haven't seen any mention of the steering shaft, they are a wear item and can cause free play and wander.     

Steve 

[noteven]

My little phart KW (12K front 21K rear, 160in. Wheelbase) will duck around on some of our finely maintained rutted asphalt highways. It’s partly a function of narrow width steer tires with strong casings. 

It goes straight hands off the wheel on a smooth flat road.

I have pulled trailers that are out of alignment and they will steer your tractor around. I pulled a rental highboy  the other day that front of deck was inside the shoulder line rear 34ft back was covering the shoulder line. Dog tracking 6 - 8 inches. Let go the truck wheel and the trailer would straighten out and  steer the outfit out of the lane... weeee....guy at the rental told me those trailer tires are junk don’t last long 😀

[Pete Kildow]

How long has the steer tires been on it? I have had new steer tires, wonder everywhere. Then after say 30,000 start holding a line.

IF not tires it has to be aliment. Spec's show one thing. But if the rears are off just a bit. Can and will make it hunt its own line down the road.

But most times it comes down to Caster. Will drive a person mad, and be in spec. But until you find what fits that truck. Its a tough job to fix.

[beemergary]

Another thing to check is the spring pins. Had to replace one on my old Peterbilt but has close to a million miles. It still drove ok but was on back.

 

[wcurtin1962]

I had this problem with my Freightliner semi tractor. A guy told me I had loose wheel bearings at a trucking seminar. I told him that a shop had said the bearings where OK. He replied tell them to retorque them anyways. I stopped at a shop after the seminar was over, sure enough they said the bearings where good. I asked them to retorque them anyways, after that the problem was solved.    

[Mastercraft]

My truck did the same thing when I got it, a lot of work making it go straight.  It had more than 1/4" of toe in.  Adjusted to zeroish, no more wander.

Be very careful cranking on the steering box lash adjustment.  The real procedure for adjusting lash involves taking off then link that goes from the arm mounted on the box to the left steering knuckle. Wiggle the arm back and forth to detect any play. Loosen or tighten the screw just enough to get no play, then tighten the lock nut while holding the screw position.

If the lash is tightened beyond zero, it will eat the steering box in short order.

Best

Rich

[wcurtin1962]

How is the gap on top of your pitmen arm? If it's under an 1/8 inch it needs to be replaced.

[noteven]

Also be careful “tightening” the steering gear - if you take up wear that may be present in the straight ahead position raise the steer tires off the ground and put the tiller hard over in both directions. If the steering gear jams tight in a full turn position say, “I’m glad I checked that.”