how to correct castor on lifted straight axle suburban

[orange72sub]

Hey guys I am building my dream truck a 1972 K20 suburban, it already has a 4-6" lift on it. The truck is a handful when driving down the road. It rides on 35"x 12.5"x16.5 BFG all terrains. I am going to do a cross over steering upgrade from ORD. But still think something needs to be done with the castor to get the truck to want to stay straight and not continue to wander all over the road. I know I need to keep the drive shaft angle as in line as possible to keep from wearing out the universal joints. Do I have to have the axle knuckles cut off and rotated to fix this? What degree of angle should I have them reset too if so? I don't plan to off road this truck but I do plan to drive the wheels off of it figuratively that is. I would like to know that my son or wife could jump in it and feel comfortable about them being able to drive it. Any help would be great thanks!

[kwmech]

Steel degree wedges. What is the caster at the moment

[special-K]

Yeah, make sure caster is the issue before messing with that. I've had various 4" and 6" lifted trucks and they went down the road straight with no changes made in alignment. Is the toe-in set right or is it Towed out. That will make it wander

[orange72sub]

I am not sure of the settings at the moment I had an alignment done before I started the restoration and the truck still likes to wonder on the road. I checked and replaced the worn out ball joints and tie rod ends pryer to the alignment. Thats when I read that the crossover steering conversion would help fix this problem too. Has anyone had this same issue with the BFG all terrains? They have a very flat and sharp edged tread. They are dry rotted and I am going to have to replace should I go to a different tire with a more rounded edge to the tire?

[argonaut]

Crossover steering will cost you a bunch of money and won't really do anything to solve the problem. In fact the addition bumpsteer from the passenger side might make it worse. Does it already have a raised steering arm, or a dropped pitman arm? The raised steering arm would be preferred.

You need to get an angle finder. Park the burb on a flat surface and measure the angle of the surface. Then measure the angle of your axle "C"s. The difference between the two is your vaster angle. Make sure it is at least 4 degrees, preferably 6 degrees. You can used shims to adjust this. I recommend steel shims, and I always use them in pairs; one on top and one on bottom of each leaf spring to keep everything orthogonal. Beware that this adjustment will probably worsen your pinion angle. So check that too.

Secondly make sure your tie rod and drag link ends are not old and sloppy. Also make sure your tires are properly inflated.

[argonaut]

Also, how is your steering gearbox? Any play in it?