Your Caster angle is out
when alignment shops check your alignment on a solid axle rig (specially a lifted one), they always insist that the caster is non-adjustable, and they are wrong. You probaly changed the caster when you installed the front lift springs, the lift springs may have even came with a caster shim to help out on front driveshaft angle, but when you roll the pinion up to help your driveshaft angle you take away caster in your front end unless you rotate the pumpkin on the tubes and re-weld it.
you need to have a alignment shop check your caster and tell you exactly how much it is out, then go get a shim to rotate it that much, or remove a shim that you might already have
Thick part of the shim to the front of the vehicle= less caster
thick part of the shim to the rear of the vehicle= more caster which also
Don't go overboard though, the more caster you add the harder the steering will feel and the more the truck will want to track road crown and such, just add enough to get the wobble to go away. Also, the wider the wheels you have are (read the further the tires are from the ball joints) the less tendancy the wheels will have to wobble and the less caster will be required (remember, the factory spec was for stock wheels with stock tires which always requirs more caster to keep steady), that distance helps the wheels "drag" on the balljoints, therefore helping it stay in a more consistent direction
i personally have 6" pro comp springs on the front of my 74' K20 with 10" wide wheels, stock shackles, no caster shim at all and unbalanced 36" swampers, and this truck has a shake from the unbalanced tires, but absolutely NO hint of any death wobble no matter what bumps i hit ( and trust me i know what death wobble is, i've had a 79' k10 do it and i also lifted a solid axle cherokee /forums/images/graemlins/eek.gif /forums/images/graemlins/rotfl.gif)
I plan on adding longer shackles which will increase caster angle and worsen my front shaft angle plus my trucks steering has alot of resistance to it and it tracks road crown pretty aggressivly so i plan on installing 4" caster shim's with the thick part to the front which should counteract the effects of the shackles and then some which will allow it easy steering, a decent driveshaft angle, but an increased tendency to death wobble and wander the road so as a safety cushion i also plan on installing a Skyjacker inline dual steering stabalizer as a control item
if it doesn't act quite right after all that, then i will go down to a 2" caster shim installed the same way
be carefull when installing the caster shim's, you may need center bolt extension spacers or a taller head centerbolt to make sure that you have the center bolt reaching through the shim and the entire way into the axle locator hole the way it is supposed to
Trial and error my friend /forums/images/graemlins/doah.gif
I hope this has helped /forums/images/graemlins/thumb.gif
