Ok , here is one for ya.
My F 250 has a pretty good shimmy at around 65 to 75 but ony when going down hill. It seems to intensify on the steeper grades.
I am thinking possibly not enough caster and when going down hill the geometry changes enough to start the shimmy. It will subside as soon as it levels out.
Up hill or level it drives fine and is smooth and steers well.

Any thoughts? It has the solid front 4wd axle .

Thanks Les

 

Wow, that is a strange one.

Do you feel the shimmy in the seat, the steering wheel, the gas/brake pedals, or in the entire truck?

Does this shimmy change with speed, like change frequency when you speed up? Does the amplitude change with speed (like does it get stronger when you go faster)?

 

I think mostly in the steering wheel, but also through out the whole truck, just not as bad.

It does increase in severity with speed.

How does one adjust caster with the solid front axle ?
I assume some sort of tapered shims.


Thanks, Les

 

I just did wheel hub assembly, ball joints, tie rod ends, axle/drive shaft U-joints, entire brake job, and much more on my E99 250 and I don't think you can use shims on a solid axle w/leaf springs. Are you coasting down hill or riding your brakes a little?

 

Yes I tried coasting while in neutral , also light braking, accelerrating ,
shimmy remains constant while going down grade, subsides as soon as road levels out.
Talked to alignment shop and he said they have spacers to provide caster adjustment. Going on Tuesday, will post results.

thanks to all
Les