Is Plastic Deformation the Cause of Death Wobble?
JK Newbie
Joined: Dec 2008
Posts: 31
Likes: 0
From: Clarks Summit, PA
I did experience DW on my stock JK X. I believe it is due to the fact that the suspension is higher than that of the TJ and this why older stock Jeep's have not had this issue. My problem was corrected when I had it aligned and replaced the steering stabilizer.
I applaud the bolt/bushing theory. This is something I never would have thought of nor even dreamed of testing. I guess it safe to say you should use all new hardware and bushings when adding new parts.
I applaud the bolt/bushing theory. This is something I never would have thought of nor even dreamed of testing. I guess it safe to say you should use all new hardware and bushings when adding new parts.
Last edited by mcaden; Apr 5, 2009 at 10:14 AM.
JK Super Freak
Joined: Sep 2007
Posts: 1,258
Likes: 1
From: Roanoke,TX
The other part of the theroey is that the center busing may not be hardened to specifications and it may be plastically defoming under load. This might explain why some of us are seeing "threads" inside that bushing and some do not. If the bushing was harder material than the bolt how could the bolt leave marks in its surface. If the bushing was harder material than the bolt and the bushing was slamming around during DW woultdn't it damage the threads on the bolt?
JK Newbie
Joined: Oct 2008
Posts: 57
Likes: 1
From: Tracy, CA
I think the cracked brackets are being caused by death wobble and not the other way around. Metal likes consistant loading, NOT impact loading which it receives during death wobble.
On another note; I wonder how many people who "just know" they torqued the TB bolts to 125 lbft really did that? I'd be willing to bet that a decent portion of the prople who claim to have torqued to spec didn't use a torque wrench. I say this because without a torque wrench I bet they stop short because 125 lbft is a frightening amount of "twist" to put on any bolt. Frightening, seriously. A week ago Benmar and I put on my OME lift and when I torqued the TB bolts to 130 lbft it slid me across the garage floor. Now, I'm a fireplug of a guy, only 5'7" but 230 lbs and it laying on my side I had to brace my feet against the tires to keep myself from sliding before reaching 130 lbft. All the while I was wincing, just waiting for the bolt head to wring off. I actually jumped a little when the wrench "pinged". Yeah, so maybe I'm a coward and you're a manly man but I'd be willing to bet that if you used a breaker bar instead of a torque wrench you stopped well short of the specified 125 lbft.
On another note; I wonder how many people who "just know" they torqued the TB bolts to 125 lbft really did that? I'd be willing to bet that a decent portion of the prople who claim to have torqued to spec didn't use a torque wrench. I say this because without a torque wrench I bet they stop short because 125 lbft is a frightening amount of "twist" to put on any bolt. Frightening, seriously. A week ago Benmar and I put on my OME lift and when I torqued the TB bolts to 130 lbft it slid me across the garage floor. Now, I'm a fireplug of a guy, only 5'7" but 230 lbs and it laying on my side I had to brace my feet against the tires to keep myself from sliding before reaching 130 lbft. All the while I was wincing, just waiting for the bolt head to wring off. I actually jumped a little when the wrench "pinged". Yeah, so maybe I'm a coward and you're a manly man but I'd be willing to bet that if you used a breaker bar instead of a torque wrench you stopped well short of the specified 125 lbft.
You sound like me!! I am 5'7" and about 200 lbs, I had my JK on a roll-on lift when I did mine (all weight on the wheels) and was doing pull-ups on my tourque wrench to get 130lbs!! 130 is no joke, i think I would need a second person to get to 150lb/ft like some people have done.
JK Enthusiast
Joined: Sep 2007
Posts: 244
Likes: 0
From: Plano, TX
You sound like me!! I am 5'7" and about 200 lbs, I had my JK on a roll-on lift when I did mine (all weight on the wheels) and was doing pull-ups on my tourque wrench to get 130lbs!! 130 is no joke, i think I would need a second person to get to 150lb/ft like some people have done.
JK Freak
Joined: Jun 2008
Posts: 655
Likes: 0
From: St. Peters, MO
You sound like me!! I am 5'7" and about 200 lbs, I had my JK on a roll-on lift when I did mine (all weight on the wheels) and was doing pull-ups on my tourque wrench to get 130lbs!! 130 is no joke, i think I would need a second person to get to 150lb/ft like some people have done.
JK Newbie
Joined: Mar 2009
Posts: 24
Likes: 0
From: San Jose, CA
I think the cracked brackets are being caused by death wobble and not the other way around. Metal likes consistant loading, NOT impact loading which it receives during death wobble.
On another note; I wonder how many people who "just know" they torqued the TB bolts to 125 lbft really did that? I'd be willing to bet that a decent portion of the prople who claim to have torqued to spec didn't use a torque wrench. I say this because without a torque wrench I bet they stop short because 125 lbft is a frightening amount of "twist" to put on any bolt. Frightening, seriously. A week ago Benmar and I put on my OME lift and when I torqued the TB bolts to 130 lbft it slid me across the garage floor. Now, I'm a fireplug of a guy, only 5'7" but 230 lbs and it laying on my side I had to brace my feet against the tires to keep myself from sliding before reaching 130 lbft. All the while I was wincing, just waiting for the bolt head to wring off. I actually jumped a little when the wrench "pinged". Yeah, so maybe I'm a coward and you're a manly man but I'd be willing to bet that if you used a breaker bar instead of a torque wrench you stopped well short of the specified 125 lbft.
As for new hardware; that's cheap insurance and I would certainly recommend it. However there are two parts that could deform and therofre lessen the holding power of the hardware. One is the bolt and the other is the TB bushing. If you have evidence of threads inside your bushing you have problems.
MB
On another note; I wonder how many people who "just know" they torqued the TB bolts to 125 lbft really did that? I'd be willing to bet that a decent portion of the prople who claim to have torqued to spec didn't use a torque wrench. I say this because without a torque wrench I bet they stop short because 125 lbft is a frightening amount of "twist" to put on any bolt. Frightening, seriously. A week ago Benmar and I put on my OME lift and when I torqued the TB bolts to 130 lbft it slid me across the garage floor. Now, I'm a fireplug of a guy, only 5'7" but 230 lbs and it laying on my side I had to brace my feet against the tires to keep myself from sliding before reaching 130 lbft. All the while I was wincing, just waiting for the bolt head to wring off. I actually jumped a little when the wrench "pinged". Yeah, so maybe I'm a coward and you're a manly man but I'd be willing to bet that if you used a breaker bar instead of a torque wrench you stopped well short of the specified 125 lbft.
As for new hardware; that's cheap insurance and I would certainly recommend it. However there are two parts that could deform and therofre lessen the holding power of the hardware. One is the bolt and the other is the TB bushing. If you have evidence of threads inside your bushing you have problems.
MB
John