If i happen to hit a bump just right with my 77 F150 stock lift 4x4 the front end will take off like the front wheels are just going left to right as fast as can be... does it only around a certain speed which is around 25-30mph... acts very similar to what a leaf sprung chevy my buddy has did..and i assume other leaf spring front end trucks would do this as well.. but his problem was the eyelets in the end of the springs were stretched out letting the front axle move back and forth... however i've been all over the front suspension on this thing... ball joints..tie rod ends... drag link...c-bushings...radius arm bushings.. track bar bushings... and mounts to make sure they were tight... steering box and bolts...checked frame for cracking where steering box mounts..pitman arm... steering dampener.... whatelse is there... the truck used to have 33" tires on it when it first did this... the issue i thought was the track bar...b/c the bushings were gone... replaced them and it was good but i only drove it for a short while and then put 35" tires on it and it seems to be more apt to happen.... i know the bigger tires would make bad things more noticeable... but i'm plum outta ideas. Hoping someone has had a similar problem.

 

ohhhhhhhhh, the old F-150 shimmy...Idid everything you did, replaced everything tried from radius arm bushings to ball joints to tires you name it i tried it. finally! I fixed it for good and never had to feel that again! well i bought a 250!

 

my buddy has a 75 f350 dually that did the same thing it was something in the gearbox, i dont know for sure what he did but i guess it was a simple fix. so, i would check there..

 

You may have the right idea with the track bar. My 78 F-150 did the same thing with a 4" lift and 35" tires, and had it on the lft several times, trying to figure it out. Finally, after much looking, tightening, and screwing around, my buddy took about a 5' steel pipe, and wedged it between the frame and the track bar, and pulled on it. The bar moved quite a bit when he did that. I got on it with a 1/2" breaker bar and gave it all I had. Even though the bolts for the track bar seemed tight, they were not. Once they were tightened, the problem disappeared. It's been about 25,000 miles with no death wobble.

 

did you lower the track bar w/lift they dont supply the bracket on 4" kits my did the same thing till I lowerd the track bar two match the upper tie rod bar in angle also make sure the tires are balanced they can cause wicked shakes

 

Yes, my kit came with a drop bracket. When we installed it, we thought it was tight, but did not realize how hard you had to crank down, to really make it tight.

 

If you dont have a steering dampner get one if yours is old get one fords have a bad problem with steering motion when these trucks are stock height let alone lifted. Cant tell you how many trucks i installed them on back in the 70s workiong at a local dealership. Try one you'll like it. chuck

 

i have a steering dampner on the truck... i even replaced the one that was there back when this first happened as it was junk....this one has good resistance both ways and seems to work... as for the track bar brackets... they are tight.. now the tires aren't balanced... and i know that they should be but the 33's that were on there b4 were balanced... and this is not a wobble from a unbalanced tire...way worse then anything a tire could cause.. it's so bad i don't know why something doesn't break when it has the spells...if you can picture how a truck will get a front end wheel hop, like when pulling at truck pulls and such... and the front tires jump back and forth...it feels like a motion much like this... just going down the road... and it just increases in intensity once it starts...u have to come down on the binders slow the puppy down till it stops.. and then try again.. lol as for the gear box... it had a tight spot in it a while back but has seemed to disappear.. there's not much slop in the steering... truck drives pretty well going down the road... i don't really see what the gear box could play in this... but i'm not an expert at power steering either.. while were on this subject the p/s doesn't work well when the truck is slowly moving or not moving... i suspect it's the pump... and i don't think that it's related to my problems..but just want to let everyone know all the symptons.. cause maybe i'm not seeing something.

 

How long have those c-bushings been in the truck since the problem started? Were they replaced during a recent lift kit? How did you make room for 35" meats after the 33's. Did you use a coil spacer by chance? The steering symptoms would indicate a poor caster angle. Too much, and the truck will act like the worst shopping cart at the grocery store.

 

Double, triple, and quadruple check that track bar! I forgot, until you just mentioned it, but I also had the exact same problem with a tight spot in the steering. That also went away when the track bar was (for real) tightened. I don't know what one has to do with the other, either, but it's probably due to the steering geometry being thrown off. You are right about the wobble being way worse than anything an out of balance tire could do. When mine threw a fit, I was pretty sure I was going to wreck it. It always seemed to start when I would hit a bump in the road, such as a pothole, or a joint where the road meets a bridge.

I'm not doubting your abilities or know how, but I didn't doubt my own either, and it turned out to be that stinkin' track bar. Good luck.

 

thanks roush i'll make sure i check the track bar again... right now i have the rearend out of the truck due to a self destruction.. i'm suppose to get it back on monday so hopefully i'll be able to get a second look at it monday night... as for the caster situation... the truck has the same c bushings in it as i bought it with...however they are not all cracked up, or pushing out of the sides or showing any wear, so i'm pretty sure they are good.. and incase some are confused the truck has no lift... it is bone stock in the area of suspension height... there is no coil spring spacers nothing... something i've noticed though is the truck sits higher then my other truck which is a 78 F150 4x4 and the brackets that the radius arms go into....i'm talking about the brackets that bolt to the tranny crossmemeber... they are longer meaning they come down further off the frame on the 78 this would change the caster, correct? and why would they be longer on a truck that sits lower? i would think it would be the other way around?... and both brackets are factory looking... not home made... and i just want to thank everyone who is responding.

 

Ford Shimmy?
BTDT! :)
Fix orders:
"something's loose"

Don't go trying to peck-at that sucker, take it apart and fix or replace everything that's loose or got play in it.

Adjust toe-in to the straighter-side of spec (spec is: 0" to 1/8") so go with 0" to 1/32" toe-in.

Done.

Alvin in AZ
http://www.panix.com/~alvinj/file12/toe-in1.jpg
http://www.panix.com/~alvinj/file12/toe-in2.jpg