I have a 1991 F-250 2WD. I get a wheel shimmy when I hit a bumps or on a rough road. It does not happen all the time It was really bad and I replaced the axle bushings. The left bushing was almost gone and the wheel had 2-3 inches of play in it. This seemed to correct the problem, but it started again. It is not as bad as it was before the bushings were replaced. The steering and suspension components are tight and in good shape. Any suggestions?

 

No one else has answered so I'll take a shot as a couple of things come to mind which make me want to ask a couple of questions so we can refine the possible causes.

1. Did you have the front realigned after your replaced the bushings?
2. If the previous problem had created uneven tire wear did you rotate the tires or replace the damaged tires? If they were rotated were both of the fronts moved to the rear axle?
3.If the tires didn't show damage did you rotate them any way (again both fronts to the rear) to eliminate the possibility of a bent rim or warped wheel or a busted cord or belt inside the tire that doesn't show on the outside? I had a busted belt that didn't show up untill I hit about 60 and then it nearly bounced me off the road.
4. Were the lug nuts checked for proper torque after about 50 - 100 miles? I know that's basic but I also screwed that one up once myself and I also had a tire shop mount a wheel wrong on my old 77 3/4 ton once.
5. I doubt it's a steering problem as that might make it wander but shouldn't create a shimmy. Did you mike the tie rod ends for wear?

If you've done all those things I'm fresh out of ideas but maybe the answers will help someone else with more experience and/or expertise pinpoint other possible causes.

Don

 

Jack up the front end and check the wheel/bearing for wiggle.......

 

Which bushings have you replaced? Did you replace the radius arm bushings also? How are the rest of the steering components, tie rods ect?

 

Have you a steering damper fitted? If so it may be shot, if not it may be worth fitting one.

 

If your upper and lower ball joints are tight and your steering linkage ball joints are tight then an aftermarket steering damper would be a good thing to add. Not very expensive and easy to install.

I had steering shimmy on both my 91 and 93 and the steering damper made it all go away.

Of course make sure all your joints are tight, tires are properly inflated, no excessive play in the steering box, bearing are good, etc.... before installing a steering damper.

 

When was the last time the front wheels were spin balanced? Preferably on the truck but NOT a bubble balancer.

 

I am going to purchase new tires to see if it will alleviate the problem. How hard is it to change out the radius arm bushings?

 

If the old tires are worn out they need to be replaced but before investing in new tires try to figure out the problem or the problem is likely to ruin the new set of tires. If they are not worn to the point of replacement fixing the problem may allow you to get a few more thousands of miles out of them.

An out of balance tire should shimmy any time you hit a certain speed not just when you are on a rough road or hit a bump. The tires themselves can help pin point or eliminate the problem causing the shimmy. An internet search for "tire wear patterns" should turn up both pictures and explanations of how different problems can cause the various wear patterns. A lot of the tire wear patterns have multiple causes and it's important to know which position the tire is running in when the wear is occuring but once you identify the wear pattern you will have a small list of a few possible problems and a big list of things that aren't the problem.