I do have a Detroit in the rear and can sense it has a tendency to pull I guess that is just something I have to live with. I've now gone back and checked and retorqued all of the bolts. The rear springs are definitely not soft, if anything, they're probably a little too stiff
I have had and witnessed the change in direction on and off the throttle in a few jeeps before. It was because of the Detroit locker in the rear and the soft rear springs with no traction bar. The jeep with a healthy small block would torque to one side so the spring was twisting up and the locker was pushing both tires in one direction. Since the jeep was so short it would feel like nose was going in a different direction when you would let in and out of the throttle.
I don't know if I explained this very well, but I would take a look at your rear suspension and see if anything is loose. Maybe the springs are to soft and causing a little axle wrap on one side and changing the direction?
Dust, as far as I know they're parallel, but that is definitely something worth looking into.
Are the front and rear axles parallel with each other?
Andy, I know what you mean I don't think anyone else would want to drive mine either. The wandering is really pronounced when getting off the gas, it almost feels like something is unwinding. Again if that's a symptom of the the detroit I can live with it, I just want to make sure I'm not overlooking anything.
I'll certainly check the wheel base, but I do know the last shop I was at said that one of my rad arm drop brackets was about a 1/4 of an inch lower than the other one. I'm not an expert by any means but couldn't that translate into a much higher number the closer to the axle housing it gets??
The tube has been checked and as far as I know is straight. I haven't personally put an angle on it but the guy at the shop said it wasn't bent..I do need to go back and find what the toe is.
Mine veers right just as you describled
sometimes i think i'm the only person brave enough to drive my bronco. it crab walks, veers right, and generally wanders left to right with vague steering. i've tracked down most of the problems.
it crab walks because the rear axle is ~3/4" off center, but with the 14 bolt in back the pinion is centered (vs 8.8 where it is offset) slightly to accomodate fords off center drivetrain idea. if the axle were "centered" i would have some pretty nasty compound angles at the pinion. broncos are also heavier towards the passenger side.
it veers right because of the detroit, staying on the gas noticeably improves straight line tracking. its not bad enough to make you change lanes, but you won't forget its there. not sure how long you've had a detroit, but it sounds like 75% of your problem.
it veers left and right because it has worn out leaf springs in front with no pan hard in front, so it is directionally challenged.
not sure how any of this helps you, but it is ideas as to what causes drive ability problems. i would check your wheelbase, and compare left to right. then i would check your radius arms, and mounts for front/back equal positioning. then i would tighten every single bolt i could find. have you checked your toe in/out? the unequal wear sounds more like a ball joint issue.
heres the big whopper question: is your axle housing straight and not bent from a crash, heat warping etc?