Death Wobble / Caster correlation?
08-27-2010, 09:35 AM
#21
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08-30-2010, 07:26 AM
#22
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Well 4wd Parts techs could not find anything wrong. Said must be due to tires and steering stabilizer. 1st thing I said was "isnt the SS just a mask for a bigger prob?" Said yes it can be but mine was very "soft" and plus he said if there was something majorly wrong I should be getting the wobble way before 75 mph. I took the SS off and I could push it in and out very easily so I went ahead and bought a new one. I rotated tires and loosened upper and lower control arms and checked bushings myself - everything looks good. Retorqued it back down. Havent noticed any vibration at all so far. Hopefully it was just a combination of the "preload/load" on the bushings, crappy front tires, and the crappy SS. Any other thoughts? Thanks for all the help.
08-30-2010, 08:02 AM
#23
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You're right, Death wobble is strictly related with caster angle.
Infact, Caster angle is one of the angles ( probably the most important ) that determines the stability or maneuverability of the steering.
putting a lift ( without control arms mods ) you obviously modify your caster angle ( becomes narrower ), infact you can easily feel your steering wheel lighter to steer.
on the other side, this modification decreases the stability... so death wobble becomes easier to happen.
so, caster angle modification HELPS a lot the death wobble phenomenon, but IT IS NOT the cause.
the root cause is usually trackbar bolts loosened ( or oval holes ), warn ball joints ..... or very often something easier, like tires not well balanced or some mud glued on the rim!
obviously, more your caster angle is narrow, more a little problem ( like some mud or a not well balanced tire ) is enought to cause DW.
Infact, Caster angle is one of the angles ( probably the most important ) that determines the stability or maneuverability of the steering.
putting a lift ( without control arms mods ) you obviously modify your caster angle ( becomes narrower ), infact you can easily feel your steering wheel lighter to steer.
on the other side, this modification decreases the stability... so death wobble becomes easier to happen.
so, caster angle modification HELPS a lot the death wobble phenomenon, but IT IS NOT the cause.
the root cause is usually trackbar bolts loosened ( or oval holes ), warn ball joints ..... or very often something easier, like tires not well balanced or some mud glued on the rim!
obviously, more your caster angle is narrow, more a little problem ( like some mud or a not well balanced tire ) is enought to cause DW.
This member know what he's talking about.
08-31-2010, 09:57 AM
#24
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The DW in the video is caused by loose or worn components. There is no way that it was caused by a failing steering stabilizer. A steering stabilizer is simply a mask. It will not tighten loose bolts or fix ovaled out bolt holes.
The dealership techs are incompetent if they could not find the source.
The new steering stabilizer will eventually fail because it will not be able to continue to mask the source. The source will get progressively worse and worse until there is a catastrophic failure--like the axle side trackbar bracket welds breaking off.
The dealer tech needed to remove and inspect the bushings and bolt holes for the trackbar, trackbar brackets, and front lower control arms and brackets. He needed to inspect the ball joints, drag link joints, and tie rod end joints. He needed to have someone cycle the steering with the tires on the ground while he manually, visually, and auditorily inspected all the front end components for the source. This requires more than an alignment and "looking for worn parts."
The next owner of that TJ will end up with catastrophic failures at some point.
The dealership techs are incompetent if they could not find the source.
The new steering stabilizer will eventually fail because it will not be able to continue to mask the source. The source will get progressively worse and worse until there is a catastrophic failure--like the axle side trackbar bracket welds breaking off.
The dealer tech needed to remove and inspect the bushings and bolt holes for the trackbar, trackbar brackets, and front lower control arms and brackets. He needed to inspect the ball joints, drag link joints, and tie rod end joints. He needed to have someone cycle the steering with the tires on the ground while he manually, visually, and auditorily inspected all the front end components for the source. This requires more than an alignment and "looking for worn parts."
The next owner of that TJ will end up with catastrophic failures at some point.
Well 4wd Parts techs could not find anything wrong. Said must be due to tires and steering stabilizer. 1st thing I said was "isnt the SS just a mask for a bigger prob?" Said yes it can be but mine was very "soft" and plus he said if there was something majorly wrong I should be getting the wobble way before 75 mph. I took the SS off and I could push it in and out very easily so I went ahead and bought a new one. I rotated tires and loosened upper and lower control arms and checked bushings myself - everything looks good. Retorqued it back down. Havent noticed any vibration at all so far. Hopefully it was just a combination of the "preload/load" on the bushings, crappy front tires, and the crappy SS. Any other thoughts? Thanks for all the help.
08-31-2010, 12:29 PM
#25
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09-01-2010, 04:36 AM
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I dont think it was only the SS. The tires were worn pretty bad on the outer edge b/c of the caster being off and the preload/load on the bushings. As soon as 4WD mentioned SS I started asking alot of questions. My DW was occuring right at 75mph, dont most happen well before that? It drove great this morning, really hope I'm done with the DW. The bushings looked good, no ovaled out holes on track bar, everything torqued down to specs...I'm gonna test the ball joints this weekend but other than that is there anything else I should look for/do?
09-01-2010, 07:15 AM
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11-14-2011, 04:41 AM
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more on the death wobble "my experience"
Ok so here is my experience on the dreaded death wobble" 07 jk sahara unlimited started shaking out of the blue on the highway one day going to work when i hit bumps in the road,first thing I thought about was tires,than I tried to recall if I hit any serious potholes that could have bent something,tires looked ok besides minor tread wear,"stock jk with stock tires by the way" took it too the shop had the front tires changed to the rear just out of curiousity,it worked for about a week and than was more violent than ever,had to pull of the road and hit the brakes several times to stop it from shaking so violently it seemed like the jeep was going to flip or something at 60-80 mph,so after reading several threads on here I was thinking alingment,etc,so I took it to the tire shop,the guy immediatly said all 4 tires need to be replaced they are 5 years old,and would not even bother checking the alingment til I bought new tires,,I found this hard to believe but being that this is overseas you don't have too many qaulity mechanic's,but myself being an ASE mechanic who has worked overseas for the military as a contractor in maintenance for going on 10 years now,I had to kind of laugh at the guy,so ruling out bad front tires at first,I began looking at other things took it to another shop put it on the lift and got underneath myself,and right off the bat saw that the power steering stabilizer was leaking all over after reading several other helpful threads here it became evident that had to be the issue,people suggested everything from,shocks,to tires,alingment,etc,so i got a teraflex steering stabilizer from qaudretec sent to me,changed it last month now,,and tried to recreate the death wobble same places,etc,intentionaly hitting bumps etc,sometimes doing over 80mph,the average speed on kuwait highways here is 80-100 mph plus" and if you can't keep up they run you over",so anyhow all is good now just the steering stabilizer did not even have to change tires do an alignment anything,
