i never would have thought about dynamic balancing of the driveshaft, but i guess it would be easy enough to pour it a pint of WTF or whatever i have handy, and see how it works. i guess the only problem with this would be making a mess on the rare occasion i have reason to remove the driveline

part of why this vibration is so puzzling is that its not always constant - it fades in and out at random, sometimes nice and friendly, other times its pretty scary. i never seem to know what to expect from it

i have looked at the driveline on several occasions when its not moving, even just last night when i was down there to change a failed TSV, and i see no dents, no signs of missing weights, and i see like 4 weights up on the front end to balance it. i'll have to get the axle up on blocks one of these nights and give it a good spin as i watch.

well, with this problem fading up and down by the mile, i've been mostly confused, but it seemed to get a lot worse tonight, so i started looking around. i found both front tires to be out of round by roughly 1/8", and i know one of the rear tires was found to be out of round when i got them balanced a month or two ago. so tires still could be the issue, i could just have a whole lot of bad tires around me. i'm starting to suspect that when the tires happen to by synced up so they're out of round in the same direction at the same time, is when it really gets aggressive with me. does that sound like a reasonable guess?

i haven't had time to spin the driveshaft and watch it, the few hours i'm at home and not sleeping are spent figuring out the more urgent things.

Yes, the old tires that came with one of my trucks would do that. I'd notice it on gentle turns that it would fade in and out as the sync changed. And the vibration would hit a resonance frequency, grow out of control and turn into a death wobble at times. However that truck had some really worn out suspension at the time so it took everything badly if you know what I mean. I wouldn't consider that slight out of round an issue with good suspension, alignment, shocks, tire balance, etc.

It's an up and down vibration in the front right? Have you played with tire pressure, maybe let out 5 pounds and drive for a while. See if it's better, worse, same.

yeah, i dropped their pressure by 5 last week, and it felt maybe a tiny bit smoother when not doing the vibe thing, but with the pressure where i left it, now we're getting uglier
we've talked about my suspension - all bushings and shocks new last summer, springs are probably original, all tie rods less than 2 years old, kingpins only slightly worn, but on the list for replacement this summer.

i think i'm gonna swap front tires for the other pair of those 16.5s to see if my vibes go away for a day or two, or what happens

well, this morning i swapped out the front tires for the other 16.5s, and it drove perfect all day.
so for the moment it looks as if all my problems are in my tires, and whatever is making them fail all the time. knowing my luck, i'll probably be complaining about new vibrations in a week or two when these tires start screwing around like the others.

Question.... I have and 89 Bronco 2 I have a front end vibration, if I take the calipers off they free spin good rotation. I put the calipers/pads back on and it gets one two rotations... I have replace the rotor/hubs, the calipers, and pads. I have also regreased the bearings twice. When the caliper isn't on the rotor has free spin, caliper on doesn't spin but one or two rotations.... with this I also have a vibration in my front end... can someone give me an idea of what the problem could be..

Rotor rotation affected whether calipers are in place or not suggests an issue within the caliper itself. Could be a piston hanging up, a warped rotor or something between the master cylinder and the caliper, possibly the flexible brake hoses. Even with calipers properly fitted the rotor shouldn't spin too freely though.

Any other vibration could be from a lot of things but most likely one or more worn steering parts. All those should be tight, not a bit loose. Not familiar with the '89 Bronco suspension but if ball joints or king pins those too might be at issue.

Last but not least just like Josh tires and/or bent wheels are another possible source.

Good luck with this----please let us know what you discover Billy Goat The Beast! :)

Well I know it is a brake issue over the axle. It has the twin axle, but I know it's the brake cuz the passenger side smells horrible when ever I drive anywhere. So it's something with the passenger side.

Uhm disk brakes always drag a little bit, in particular when first put together. That's just how they work, what you describe is normal.

Your also talking about a Bronco II in a thread about a thread and forum section about full size vans. You should as your question with a new thread here https://www.ford-trucks.com/forums/forum34/ in the Bronco II section.