So, I just read through this entire thread and would like to add something.
My '53 1/2 ton is my only vehicle, so it's driven on a daily basis. As I read through this thread I began to wonder what it was I had done through the years to eliminate bump steer on my truck. Even if I hit a bump at speed big enough my front and back tires leave the ground my truck stays straight (for the most part). No involuntary lane changes. I've decided that you never fully eliminate bump steer, but:
1) Relax, fighting bump steer makes it worse.
2) You can minimize the causes and effects of bump steer. Only in the most extreme cases do I experience bump steer because I've found that:
a) When your tires are too hard your suspension reacts to pot holes, etc. more violently. When your tires are too soft the truck reacts too sloppy and recovers slow.
b) Steering and suspension geometry are key.
c) Wheel bearings, king pins, tie rod ends, steering gear box, spring mounts, bushings, shackles, etc, etc., have to be tight/no slop.
d) REAR spring mounts, bushings, and shackles HAVE to be TIGHT or bump steer will bounce your front end one way and the rear end the other way. Impromptu slalom course anyone? The last time I started to notice a return in bump steer I found my rear shackles were toast. When I replaced them it eliminated bump steer in all but the worst cases.
In other words there's no magic bullet (other than maintenance).
