I have a 4" lift on my m1008 been running 33 duratracs with no DW problems. I came across some Humvee 37s and put them on the truck and now cant go over 35mph without extreme DW. Im thinking its the kingpins. But I don't know why I never had any DW with the 33s. Has anyone else run into this problem. I got the 37s balanced so I don't think that's the problem.
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Mounted HMMVE 37's now extreme death wobble
- Thread starter Sp0okfish
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My guess is it is the springs and bushings in the king pin assembly.
There is more leverage due to the taller tires is what I would think.
I started off with the HMMVE 37's and had the same problem. I
switched to 35's and it mostly went away. I still need to do the king
pin assembly over haul, but haven't had the time. So as long as I am careful
and just use it for short trips around home, it behaves.
There is more leverage due to the taller tires is what I would think.
I started off with the HMMVE 37's and had the same problem. I
switched to 35's and it mostly went away. I still need to do the king
pin assembly over haul, but haven't had the time. So as long as I am careful
and just use it for short trips around home, it behaves.
Skinny
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Try rotating front to back, you may have a bad tire. It will spin balance up fine but loaded with vehicle weight it will show up.
Skinny
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I would consult the TM on how to check. It's been awhile since I've done a kingpin axle and my brain is overloaded with other more important useless information about airplanes, boats, beer, and women. Wait...scratch women...
timarr
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40 bucks. change springs and cups. Had same problem. Hit a bump and would start. now its all good!
Keith_J
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Yes, upper King pin bushings and springs. The reason for springs is to give some play while still maintaining even lower bearing preload with a cylindrical bushing...ok, it is conical but same ideal. Now if it were a ball joint, there would be no need for springs and bushings but who knows the engineering decision at Dana.
Death wobble is nothing more than precessional oscillation, much like a toy top wobbling. The speed at which it happens is based on the mass of the rotational assembly (wheel) and the spring force of the bushing springs. Actually the spring constant, works out to frequency or speed is an equation of the square root of the spring constant divided by the mass...but that is highly simplified. Any how, when the springs get weak or the mass increases, the frequency gets into the range where it is a problem.
Death wobble is nothing more than precessional oscillation, much like a toy top wobbling. The speed at which it happens is based on the mass of the rotational assembly (wheel) and the spring force of the bushing springs. Actually the spring constant, works out to frequency or speed is an equation of the square root of the spring constant divided by the mass...but that is highly simplified. Any how, when the springs get weak or the mass increases, the frequency gets into the range where it is a problem.
Skinny
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I'm not sure how we drew a conclusion that it has to be kingpin related. Sure, someone that has DW and replaces the kingpins which eliminates the DW could draw that conclusion. Regardless of what that explanation is trying to get at, DW can occur from any frontend component that is worn out and is amplified by larger/heavier/offset tire assemblies. This could be a worn out spring bushing to a spot in the steering box out of spec for whatever reason.
Until you or a technician have performed a careful inspection of all components and swapped tires around, I think pointing to the kingpins as the sole source of DW is jumping the gun.
Until you or a technician have performed a careful inspection of all components and swapped tires around, I think pointing to the kingpins as the sole source of DW is jumping the gun.
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Yes it is jumping the gun, but on an old truck it is probably
a good idea to replace the springs and bushings. And although
I haven't done this myself, it looks to be a reasonably easy
procedure. Just my two cents.
a good idea to replace the springs and bushings. And although
I haven't done this myself, it looks to be a reasonably easy
procedure. Just my two cents.
richingalveston
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Even the stock springs may not be strong enough on a large tire. I had DW with new springs and cups. Added two washers to load the spring more and it quit. I changed to the springless kit and still use one extra washer.
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Hey Rich, got a link to the springless kit? Also Do you
remember the size of the washer you used so I'll
have everything ready when I tackle this job.
Thanks a bunch!
Bruce
remember the size of the washer you used so I'll
have everything ready when I tackle this job.
Thanks a bunch!
Bruce
richingalveston
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http://offroaddesign.com/catalog/Dana60UpgradeParts.htm
I don't know the size but they were large fender washers. The washers go on top of the rubber. Just make sure the lay flat in the top of the cup. Make sure you use washers and not just flat metal stock. The hole is needed in the center for grease to travel through. The rubber has a hole in the center for grease to get to the plastic bushing.
I don't know the size but they were large fender washers. The washers go on top of the rubber. Just make sure the lay flat in the top of the cup. Make sure you use washers and not just flat metal stock. The hole is needed in the center for grease to travel through. The rubber has a hole in the center for grease to get to the plastic bushing.
Skinny
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Agreed, something on my list of things to do since I have no idea if mine have been replaced recently. Judging by the rest of the truck, probably originals.
Skinny
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Is that kit OK for a daily driver vehicle? Probably worth the money to install if you are in there doing a rebuild anyway if it will stand up to lots of miles.
richingalveston
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I drive my truck as much as possible. If I am not working or needing to pull one of my trailers, I am driving the blazer. I believe these springless kits have only been out for about 2 years or less so only time will tell how they hold up. It is just a piece of rubber so I cant imagine it not lasting. I plan to put the bronze bushings in next time I break things down but for now, no complaints on the springless kit.