Little background, my 40 has a spring over and shackle reversal I did years ago, then didn't drive it for a long time, now driving it again. I would sometimes get the start of what felt like death wobble but then it'd go away. For awhile I didn't have any shocks on the vehicle at all, so some wierd shakes were to be expected I figured, but nothing was horribly bad. Lately (~2 weeks) it's been getting worse, on certain roads I would get full-on death wobble, front-end all over, tires whipping around, really violent. I'd slow as quick as I could, it'd go away by about 5mph then I could speed up again. (I had shocks on the front now, Rancho 9000s on the highest setting typically)
Since this was getting worse I figured I needed to do something. I shook the tires and noticed the wheels had some play, they could move some without the hub moving, obviously wheel bearing problem. So I tore into that and rather than just tighten the wheel bearings I figured I should do a full knuckle rebuild, I've never done one on this and at 145K miles probably time.
I get in there and the top trunion bearings definetly have some wear, little grooves from the rollers, etc. I put in all new trunion bearings and races, put it all back together (reused wheel bearings which looked fine, but I cleaned and repacked them). I got it all together last night and let my dad borrow my other car for a few days since I was all done and obviously everything would work out fine. Well this morning I take my son to daycare and holy hell, instant death wobble at 40mph, extremely violent, I slow like I normally would, already kinda pissed at the situation, then speed up again when it's stopped, I hit 40mph again and bam, same thing. After the 2nd time I decided this wasn't going away, this is what was going to happen. So I ran with my flashers on at 30 mph all the way to my son's daycare, totally sucked. Come back home before going to work and figure something has to be visibly wrong, I shake the wheels and wheel bearings seem loose again, WTF!! So I tighten the hell out of them, just to totally eliminate that possiblity, didn't fix a thing, just as bad as what I just felt.
So I limp the vehicle to work at 30mph with flashers on, get the finger, yelled at, etc, but that's fine. At work I remember that I swapped tires last night, front right became front left and so on, just did it to maybe even out some scalloping on the front tires. Since the problem is huge now obviously some tire must be bad and I've gotten it into a worse area. I'm thinking about the geometry of the frontend and it seems to me it would be hard or impossible for the front left tire only to generate death wobble and bump-steer, since the front left could cause the front right to tip out when it went up but thats all, no real direct linkage there IMO. So I figure the tire on the front right now must be jacked kinda, so maybe it was semi noticable over on the left, but now on the right when it starts bouncing from being out of balance it can directly affect the steering and get into a death wobble situation. That rim has tons of weight on it, some have been ripped off, some scratched badly, I was thinking maybe the weights have moved so they are doing more harm than good, and I might as well rip the weights off since a unbalanced tire can't possibly be worse than this. So I rip all those weights off and start driving home, bad idea! Now the death wobble starts at 25mph, I kid you not. 25mph and it'll go freaking crazy jumping all over, scares the hell out of me! I make it about 2-3 miles then give up and call my stepdad, and go back to there and borrow his car.
So, I'm pretty sure the tire is out of balance (I know it is now since I ripped all the weights off), but what else? Front end and knuckles are freaking tight, not a ounce of play anywhere there. I did not actually measure trunion preload but it's much tighter than with the old bearings yet death wobble is easily 100 times worse! It wouldn't surprise me that a bad tire could do some of this but it seems very extreme, I've seen unbalanced 37's that didn't shake this bad, these are mostly worn Goodyear 35's.
The death wobble also gets worse when on the brakes sometimes, like it will kinda feel like it's going, then you touch the brakes to slowdown and it really goes, not sure if it's related to the brakes or maybe just when slowing some weight transfer to the front.
I guess I'll get the tires balanced, pull them all off and put in a trailer, no way I'm driving that thing again in that condition, WAY too dangerous!
Since this was getting worse I figured I needed to do something. I shook the tires and noticed the wheels had some play, they could move some without the hub moving, obviously wheel bearing problem. So I tore into that and rather than just tighten the wheel bearings I figured I should do a full knuckle rebuild, I've never done one on this and at 145K miles probably time.
I get in there and the top trunion bearings definetly have some wear, little grooves from the rollers, etc. I put in all new trunion bearings and races, put it all back together (reused wheel bearings which looked fine, but I cleaned and repacked them). I got it all together last night and let my dad borrow my other car for a few days since I was all done and obviously everything would work out fine. Well this morning I take my son to daycare and holy hell, instant death wobble at 40mph, extremely violent, I slow like I normally would, already kinda pissed at the situation, then speed up again when it's stopped, I hit 40mph again and bam, same thing. After the 2nd time I decided this wasn't going away, this is what was going to happen. So I ran with my flashers on at 30 mph all the way to my son's daycare, totally sucked. Come back home before going to work and figure something has to be visibly wrong, I shake the wheels and wheel bearings seem loose again, WTF!! So I tighten the hell out of them, just to totally eliminate that possiblity, didn't fix a thing, just as bad as what I just felt.
So I limp the vehicle to work at 30mph with flashers on, get the finger, yelled at, etc, but that's fine. At work I remember that I swapped tires last night, front right became front left and so on, just did it to maybe even out some scalloping on the front tires. Since the problem is huge now obviously some tire must be bad and I've gotten it into a worse area. I'm thinking about the geometry of the frontend and it seems to me it would be hard or impossible for the front left tire only to generate death wobble and bump-steer, since the front left could cause the front right to tip out when it went up but thats all, no real direct linkage there IMO. So I figure the tire on the front right now must be jacked kinda, so maybe it was semi noticable over on the left, but now on the right when it starts bouncing from being out of balance it can directly affect the steering and get into a death wobble situation. That rim has tons of weight on it, some have been ripped off, some scratched badly, I was thinking maybe the weights have moved so they are doing more harm than good, and I might as well rip the weights off since a unbalanced tire can't possibly be worse than this. So I rip all those weights off and start driving home, bad idea! Now the death wobble starts at 25mph, I kid you not. 25mph and it'll go freaking crazy jumping all over, scares the hell out of me! I make it about 2-3 miles then give up and call my stepdad, and go back to there and borrow his car.
So, I'm pretty sure the tire is out of balance (I know it is now since I ripped all the weights off), but what else? Front end and knuckles are freaking tight, not a ounce of play anywhere there. I did not actually measure trunion preload but it's much tighter than with the old bearings yet death wobble is easily 100 times worse! It wouldn't surprise me that a bad tire could do some of this but it seems very extreme, I've seen unbalanced 37's that didn't shake this bad, these are mostly worn Goodyear 35's.
The death wobble also gets worse when on the brakes sometimes, like it will kinda feel like it's going, then you touch the brakes to slowdown and it really goes, not sure if it's related to the brakes or maybe just when slowing some weight transfer to the front.
I guess I'll get the tires balanced, pull them all off and put in a trailer, no way I'm driving that thing again in that condition, WAY too dangerous!
