Steering shimmy around 45mph
 

Truck has a shimmy around 45mph. You can let go of the wheel and it wobbles back and forth 5 to 10°. Put new shocks on before this was an issue. I've check wheel bearings, ball joints, tie rod ends, and idler arm for freeplay and everything feels tight. When I lift one side off the ground and wiggle the tire (9-3 oclock), this center link rotates forward and backward letting the toe change, probably about a 1/4". Since these are ball joints, I don't know what is supposed to constrain them so they don't wobble. Any help? These videos are with only the right side front tire off the ground.


https://drive.google.com/open?id=0Bz...VRQWHVBX1lhNHM

https://drive.google.com/open?id=0Bz...k9qTnhCLVlCRnM

https://drive.google.com/open?id=0Bz...1kzem4xMWFsUEk

With one wheel on the ground, there should be NO play.

Recheck the idler arm and pitman arm. Looks like you need new ones. They should not move up and down at all.

Maybe you should take it to a pro for proper diagnosis.

I agree with what you guys are saying. The pitman arm is tight. The idler arm has been replaced about 20k miles ago and may have a very small amount of wiggle but hardly anything. The ball joints have no detectable play. I had someone look at it that's done several front ends (no f150's) and he was confused too.

What is causing the play is the center link rocking forward and backward. These are ball joint connections. Even if I replace with new, what is supposed to constrain this motion? In the first video you can see how much it moves the tie rod, which is moving the wheel.

https://drive.google.com/file/d/0Bzh...VBX1lhNHM/view

Even though they are socket joints, they do wear out. To me, it looks as if it's way to easy to rotate that center link. The ones in my lifted 95 take a lot more than that to move.

It could be as simple as needing an alignment, wheels balanced, or even a tire. If a belt has separated in a tire it can cause some symptoms similar to yours.

Yes, but if one wheel is on the ground, the other wheel should NOT have any play like that. The idler arm should have NO wiggle.

Absolutely. I must have missed that. Sorry.

The shimmy can be a greatly out of balance or out of round front tire for some reason.
A bulge, a broken belt, plug put in to save the tire for a bit longer life etc.
A plug in a tire is only good as a spare.
After you get the new tires on then worry about the steering parts wear.
As of the moment your asking for crystal ball answers.
Good luck.

The pitman arm needs to be replaced. Looks clear to me in the second video that it is moving up and down. the tie rod ends are ball and socket and should allow some rotation. Don't take this the wrong way but you need to take it to a pro who understands how to check the steering.

I have had this issue many times because I have my torsion bars cranked up too far and it puts everything at an extreme angle because I needed more clearance for tires, then I put f350 blocks in the rear so now I'm kinda stuck with this same problem. I changed to a moog idler arm and it help tremendously but until I straighten out my angles I have to deal with it. I changed ball joints, upper control arms, everything.

One of the front tires was 10lbs lower than the other. refilled and shimmy is gone. Not saying I don't need to replace some steering parts, but it solved the handling problem.