When I was a kid, I had my 57 3100 up to 100 mph many times, it never had any sort of shaking. I would cruise 70 on the freeway .
Anytime I had an old vehicle that would do the shake deal, it was usually initiated by a nice bump in the road. Any kind of looseness in the steering system will be the reason it exists, an outa balance wheel-tire will cause it, especially dynamic balance. I've not known of a drive line imbalance causing it, though not saying it couldn't.
Small tricycle landing gear aircraft all have what is called a shimmy dampner, its like a shock absorber of sorts, the front wheel is a very loose setup and will shimmy, also some VW bugs used the same type of deal. Ive seen them added on older straight axle vehicles too, but I don't like how the after market units mount to the axle, I'd use the spring to axle U bolts and a special bracket if going that route. The old straight axle setup works good and should if it good shape not shimmy, just look at all the over the road trucks out there using that system. I'd suspect all the pivot points in that steering system, from king pins on. Also steering gear back lash.
How tight are the wheel bearings? If they are ball type they need to be slightly preloaded, and roller type have about .001 of slop. If you have to stock ball type follow the shop manual for adjustment. Loose wheel bearings can cause it too.
Also check toe in, and tire wear condition.
Last edited by Truckrolet; 05/29/2013 3:36 PM.
