[rotorwrench]

I don't think the king pin needle bearings are strong enough to hold up under the abuse that they have to take. Lots of folks have had premature failure on these.

Now if a king pin steering joint it is good condition with little play experiences a wobble or high rate feedback (other wise know as the death wobble) then there are other factors that need to be checked. Caster is set around 6 degrees positive on these old straight axles. If the wish bone ball is loose, there can be problems with the caster angle. Ford put a lot of caster into the straight axles just for this reason. It makes them harder to steer but less prone to feedback wobble.

The tires can also get their fair share of the blame in many cases. A bad carcass can really give you a problem. If in doubt, take the suspect wheel/tire off the hub or axle and roll it on a flat surface. A ply or tread separation won't allow it to roll in a straight line. They will roll to a wobble and fall over. A good tire will roll well and straight for a long time.

There can be problems with cars that have a split wishbone arrangement too. This can cause roll feedback in a turn if there is not enough allowance for tilt of the axle. The wishbone allows for full roll capability in the range of the suspension travel. The split bone set ups generally only allow movement so far then they hits the stops and start loading up in spring tension. This is usually only a problem in turns but it can be a problem on extremely bumpy roads as well.