Upgrading the front suspension with the B/F spindle and larger rotors is a great thing you can do for your G body car. The better geometry does wonders for handling and better braking is something anyone can appreciate. But, there is a minor problem, Bump steer. The steering arm of the B/F spindle is lower compared to the stock spindle. This puts the tie rod at a different angle to the lower control arm. The problem lies in the fact that the tie rod and the spindle don't follow the same arc anymore, which causes the spindle to steer the tire, as the suspension moves. This is not good, and can feel strange to the driver as the car wants to steer itself, usually in the middle of a hard turn!
The solution is to raise the outer tie rod end, or lower the inner tie rod end. I chose to try the inner tie rod method, as there is more room to play with in there. The centerlink is modified to be able to use common bump steer studs/spacer assemblies and rod ends on the inner tie rod position.
This is a pic of the prototype centerlink with the tabs just tack welded on. I wanted to make sure the setup would work before having a new one welded completely. The tabs are readily available parts. The tabs allow a bump steer stud to mount to the centerlink vertically, allowing vertical height adjustment of the inner tie rods.
Another view of the tab on the centerlink. The hole uses a standard taper for secure mounting of the bump steer stud.
Here's a pic of the finished installation. As you can see, the position of the inner tie rod end is lowered, and now runs about parallel with the lower control arm. Trial and error testing ended up with one 1/4" spacer installed. The toe change is not visible to the naked eye, but I am sure a real bump steer gauge would've been a help to set it perfect.
Here you can see both inner tie rods. There is no interference with the chassis or other suspension components. But, a steering box with stops for 16" rims is necessary, otherwise the studs might hit the diagonal braces at full lock.
The result is a better tracking, more secure feel to the front end. I could feel the tires trying to turn during a corner where the road drops off, like a top of a hill. That was a weird feeling, like something was just not right up there. With the bump steer almost eliminated, the front end feels like it should, more stable, less wander, less darting all over the road on bumpy roads (especially during cornering).
This worked out better than I had imagined, and is not too hard to fab up. My only concern is the fact that the pivot points for the inner rods have moved farther away from the pivot points on the center link. This may cause the links bearings to wear faster, but time will tell.
This page and pictures on it on property of Jeff Davidson. Page made 04/01/2002.