This just happened. I was coming out the woods from hunting and when I got on the pavement something didn't feel just right. Now when I'm parked, at idle, when I turn the steering wheel the truck shifts back and forth. I jacked up the front end and can find nothing broken or loose. First thing I thought of was the track bar, but it's got new bushings and seems fine. I need to borrow some taller jack stands so I can support it by the frame and let front axle hang. Maybe I'll find something wrong then. Edit: truck is a 1979 F150 4wd

Any suggestions before start?

 

Let it set with the weight on the tires and climb under there and watch as someone shakes the wheel back and forth (steering wheel) you will see what is loose.

 

Yep, I tried that. Can't spot anything. I just test drove it and cant tell anything's wrong now, only that slight shift while sitting still and steering wheel is turned. It does it at the apex. Turn left, truck shifts right. Turn right.....

 

The action of the shifting is something to do with the trackbar, it's mounts, or the frame.
So you had the truck on the ground and a helper steering the wheel and could see nothing going on? That's very strange.
It's normal for there to be a bit of sideways shift when a Ford truck is lifted without compensating with the trackbar mounts, but not normal for a LOT of shift. That only comes from something wrong with the trackbar mounting.
If one of the mounts is broken, the frame crossmember has separated from the frame, the lower trackbar bolt has broken loose, or something like that.
In fact, a wobbled out lower trackbar mount bolt/hole used to be so common that a company called Ingall's Alignment Products came out with a very expensive fix. A new stud with tapered sleeve and tapered reamer as a kit. Ream out the stock hole, insert the new bolt/stud/thingy, then go on your way.
But if that was the case here, you would have seen it.

Is the truck lifted with suspension components? Were a trackbar drop AND dropped pitman arm installed? If not, the extra angle can cause more shift.
But again, if you noticed it that badly after some wheeling, something happened during the trip.
Also look at the radius arm mounts, the steering box as it mounts to the frame (in other words, the frame itself for cracks) and anything in the rear leaf spring area while you're performing "the test" with the helper turning the wheel.
Typically, all you need is a half a turn in each direction continually to see most issues. A short and frequent oscillation of the wheel is not necessarily enough.

Good luck.

Paul

 

This don't help you find the problem, which is no doubt track bar but it would save a lot on the front end of your truck if you would learn to steer only then the truck is moving. Cranking the steering around while setting still puts huge forces on parts.

 

1 Ton, I'm finding nothing wrong so far, but will look more today. The suspension is stock. Like you, I keep thinking Track Bar. It's tight, but very well could seem that way under tension, so I'm going to break the fasteners loose just to make sure I'm not missing something. The cross member is intact also. This truck needs new axle shaft u-joints, so I'll probably do that and replace ball joints, tie rods, and forward radius arm bushings at the same time. I replaced the rear radius arm bushings a few weeks ago. The forward bushings are original and surely need replacing.

I had a plan to actually remove and totally rebuild the front axle assembly, but was hoping to do so after turkey season. Looks like I'll be doing it a bit sooner.

Thanks 1Ton. Willow,...yeah

 

It's the lower track bar bushing or bolt. I didn't catch it before. Using a pry bar I can move it quite a bit. Musta been something I did wrong because those are new Energy bushings. I'll pull it later this evening and find out. I hope the mount isn't cracked

 

Good find. Hope it's not too buggered, but at least you have a target now.
And yeah, when these things are under tension you simply cannot feel a loose or worn component by hand. Except in extreme situations, you just can't move that stuff without lots of torque. Either by the steering system itself, or by crowbar as you found out!

But at that, I'm shocked that you could not see it moving back and forth with the steering test. If the tires were off the ground, you'd see nothing. But with the full weight of the vehicle on the tires, that should have been enough to see the wobble. Frankly, if you can see the vehicle body move sideways, you should be able to see at least some of that movement at the bar. I guess the body was just moving too much and taking up all that move then.

Hmm, was this performed with just a quick movement of the steering wheel, or did you move it at least half a turn in each direction? A short shot might not have been enough to highlight the mount's movement perhaps.
Good luck with the fix.

Paul

 

1Ton, thanks. You asked was if it was just a quick movement....Quick or slow, it still shifted. What it is, is when the steering wheel is at center, wheels straight, when I turn either direction, the truck shifted opposite. And that says TRACK BAR all over it.

I just pulled the track bar and checked the bolt and boss. The boss is definitely wallowed a little bit. I reinstalled and tightened everything really tight. No movement with pry bar. No more vehicle shift when turning steering wheel. I test drove it and it tracks much better. It had developed a very slight "clunk" which seemed to come from the drivers side. That's gone now. Now I know the clunk was resonating from the lower track bar mount up to the upper mount.

It's good now, but all is not well. The lower mount or boss is still wallowed which means this problem will reoccur and worse. I've seen the tapered stud kits and they don't impress me because it's gonna wallow too eventually. The only way I see to fix this right, is to have a two sided lower mount that encloses the track bar end, and supports the bolt on both ends.. The upper mount is two sided and can't wallow. I'm pretty sure I see a fix. I can fabricate an outside mount that attaches to the lower shock mount. With this, the bolt will be supported on both ends. What do you think?

 

If forgot to mention that I have factory dual front shocks. The front two shocks are forward of the coil spring which puts the lower mount on the passenger shock in a good position to attach the bracket.

 

Good deal. Not sure what you mean though, by using the lower shock bracket. Isn't it farther out?
But besides that, since you never want to mount the actual trackbar to the radius arm cap (it'll shove the radius arm and bushing right off of the axle pad!) I would think you would not want a rigid reinforcement there either. I'm thinking that because the radius arm and axle twist in different directions when articulating, there will be too much stress on one end or the other. Or both.

Is that what you were contemplating? Doing the outer bracket for double-shear from the cap of the radius arm?

Paul

 

1Ton, you may be right about that. But I think when this thing gets loose again I'm gonna try it and monitor it. Fortunately, the part of the shock mount I'd be welding to is mild steel and bolted to the radius arm cap. It has some flex to it which is also good. I only had about 1/8" play anyway, so I believe if the radius moved at all, it'd only be 1/8" - 1/4". In that event, I'd change C bushings, remove my bracket, and probably go with the tapered stud. Fun stuff

 

The radius arms are torsion bars, pure and simple. The shorter the arm, the stiffer the resistance to cornering input and the harsher the ride. The longer arms do the opposite.
But any arm clamped to an axle that is allowed to move up and down at different rates left-to-right is going to impart mostly "twist" to the radius arm ends and the C-bushings. So take twist into account even more than straight sideways movements when you're figuring out your bracket.
Ultimately, the best way to double-shear something is probably with the secondary bracket attached rigidly to the same surface I would think.
Possibly welding a small bracket directly to the axle housing that you can then bolt the outer bracket for the bar to?
Just suggestions based on little working knowledge of the problem and without something in front of me to check out in detail.

Good luck. Post pics too, when you get around to messing around with it.

Paul

 

Agreed. The more I lay under the truck and look at it, the less I'm willing to risk damage to the radius arm. Yes, I thought about welding a bracket to the axle tube but that brings up another question I never thought of until I looked for a spot to weld to...Is the tube cast? It sure looks like it is. The C bushing boss looks cast, the track bar mount does too. And there's a raised number there that appears to be cast. I've looked pretty hard at it and hoped to see that it's forged instead of cast. This is one of those things that I'll obsess about until I fix or break it. Thanks for keeping me out of trouble, 1Ton!

 

A little googling reveals that the tube is probably not cast. The radius arm / track bar casting (or possibly forging) is pressed onto the tube. So maybe there is a way to weld on a bracket. I'll keep digging and pondering.