No more death wobble!

[AF Sergeant]

Hey all,
First let me introduce myself…my name is Louie and I’m a sergeant in the Air Force, going on 13 years of service. I’ve been lurking in this forum for a couple of weeks, getting “caught up to speed” as they say. I must admit there is a wealth of information here and it will take me many more months to sort through it. I bought my first FJ40 last month (been wanting one for several years). The previous owner (PO) had it as a daily driver. Almost immediately I noticed that it darted and wandered all over the road (Alaska roads are among the worst in the world with ruts and pot holes). The 40 has a 4” lift which I now know was purchased from Specter, also has 33-12.5 Firestones on 15” Eagle Alloys. I decided to take a chance and install a set of 4* shims, I figured it would be an inexpensive attempt at minimizing the death wobble. The PO warned me about the steering characteristics. It’s been upgraded to a Saginaw therefore steering is very sensitive and effortless. So the shims are ordered and they arrived on Friday. As soon as I got home Friday, I went to work on the front end. Sat morning I went looking for U-bolts and center bolts. Finally got everything installed and bolted down and took it for a road test. BIG DIFFERENCE! No more suicide lane changes and very little wondering. I even noticed that the steering wheel wants to return to center after a turn, this did not happen prior to the shims. I would say a 90% improvement from before. The stabilizer I have is shot (leaking badly), so replacing it may improve handling even more. The off road tires I have may also be responsible for following the ruts. I must say I’m extremely pleased with the results and it was not a difficult job. Thanks to all of you who have posted info on correcting caster problems. Next project…TRE’s and stabilizer.

 

[todt]

Glad to see someone handle up on some death wobble, that can be a tough one. Some never find solution.

 

[71AZFJ]

Welcome Thank You for your service . I need to shim mine also. Hope I get the same results.

 

[HighPlainsDrifter]

I'm a 60 type of guy and believe in good handling characteristics, but be careful about the front drive shaft when shimming for steering problems. Sometimes the only real way to deal with all issues of a lifted rig is a cut and turn of the front housing.But with only 4 inches you should probably be good.I'm sure a 40 guy can chime in who knows a little bit more bout it than me. Welcome to MUD, it's a site with a lotof good people on it.
-Rob

 

[skidplate]

I've never had death wobble on my '40, but it would wander and follow ruts in the road. I installed the 4 deg. shims as well. I was amazed at what a difference that little"wedge" made. Welcome! and your service is greatly appreciated. EDIT.. I have 2.5" ex. shackels.

 

[piecemeal]

Those goofy little wedges (3 deg or 4?? can't remember, from MAF) made a huge difference w/ mine as well. Only needed them in the front after HFS shackle install. Wouldn't work in back....

 

[DSRTRDR]

wander in ruts is greater with wider and less with narrower tires

there is a reason I went from 12.5s the truck came with to 10.5s

 

[AF Sergeant]

here are some pictures of the 40 i purchased and the shim job.

 

[Poser]

Welcome.

No more death wobble!

Hey all,
First let me introduce myself…my name is Louie and I’m a sergeant in the Air Force, going on 13 years of service. I’ve been lurking in this forum for a couple of weeks, getting “caught up to speed” as they say. I must admit there is a wealth of information here and it will take me many more months to sort through it. I bought my first FJ40 last month (been wanting one for several years). The previous owner (PO) had it as a daily driver. Almost immediately I noticed that it darted and wandered all over the road (Alaska roads are among the worst in the world with ruts and pot holes). The 40 has a 4” lift which I now know was purchased from Specter, also has 33-12.5 Firestones on 15” Eagle Alloys. I decided to take a chance and install a set of 4* shims, I figured it would be an inexpensive attempt at minimizing the death wobble. The PO warned me about the steering characteristics. It’s been upgraded to a Saginaw therefore steering is very sensitive and effortless. So the shims are ordered and they arrived on Friday. As soon as I got home Friday, I went to work on the front end. Sat morning I went looking for U-bolts and center bolts. Finally got everything installed and bolted down and took it for a road test. BIG DIFFERENCE! No more suicide lane changes and very little wondering. I even noticed that the steering wheel wants to return to center after a turn, this did not happen prior to the shims. I would say a 90% improvement from before. The stabilizer I have is shot (leaking badly), so replacing it may improve handling even more. The off road tires I have may also be responsible for following the ruts. I must say I’m extremely pleased with the results and it was not a difficult job. Thanks to all of you who have posted info on correcting caster problems. Next project…TRE’s and stabilizer.

Glad to see someone handle up on some death wobble, that can be a tough one. Some never find solution.

What you have gone into great detail describing here is not death wobble; in the unlikely event that you ever experience it with your small radial tires, you will know the difference.

Death wobble is not the vehicle darting from lane to lane, or not able to track strait down a road.

Death wobble is the vehicle being violently shaken due to a multiple of issues which include, but are not limited to;
large, unbalanced tires, loose/ bent wheels, loose/non-existent steering knuckle bearing pre-load, loose/damaged/broken steering components, loose/damaged leaf spring u-bolts/shackles/suspension components, etc.

Installing the axle shim returned your caster angle to a more acceptable position, which has created the vehicle tracking strait down the road again.

 

[skidplate]

Agreed Poser, I had a Ford F250 4X4 that would suddenly start shaking so violently that anything laying in the front seat would end up on the floor, and I literally could not see. Truly scary stuff!

 

[72RatCamaro]

Welcome.












What you have gone into great detail describing here is not death wobble; in the unlikely event that you ever experience it with your small radial tires, you will know the difference.

Death wobble is not the vehicle darting from lane to lane, or not able to track strait down a road.

Death wobble is the vehicle being violently shaken due to a multiple of issues which include, but are not limited to;
large, unbalanced tires, loose/ bent wheels, loose/non-existent steering knuckle bearing pre-load, loose/damaged/broken steering components, loose/damaged leaf spring u-bolts/shackles/suspension components, etc.

Installing the axle shim returned your caster angle to a more acceptable position, which has created the vehicle tracking strait down the road again.

Yeah so how do I fix that? I am thinking prob 99 percent of the problem is the 36in cheap mudders that are not balanced....but it clears up after a certain speed

 

[Isotel]

Yeah so how do I fix that? I am thinking prob 99 percent of the problem is the 36in cheap mudders that are not balanced....but it clears up after a certain speed

i think you answered your own question!

 

[todt]

Haven't started with my issue yet but I got death wobble. Starts at aprox 42 mph and is gone completly by 44-45. Not that I've ever driven in an earth quake but I think this is what it would feel like.

Yes I think the 36inch swampers have alot to do with my prob.

 

[josharre2000]

here's what death wobble looks like:

YouTube - Death Wobble

 

[MDTyree]

here are some pictures of the 40 i purchased and the shim job.

Are they steel shims or aluminum? I'm having a hard time finding steel shims.
Welcome and nice rig by the way.

 

[homebuiltcruiser]

The 36" swampers probably contribute to the problem, but can just make an underlying issue in the steering seem worse. I had some occasional death wobble with my 31's and it got much worse when i put my 35" boggers on. I have 2" over shackles and had already put shims in so i went through all the steering and ended up with worn out shackles. The PO made homemade shackles and both holes had gotten bigger because he made them slightly to wide which allowed for movement. A new set of shackles up front and no death wobble. Of course it still likes to follow ruts in the road, but that's boggers for ya.

 

[AF Sergeant]

Are they steel shims or aluminum? I'm having a hard time finding steel shims.
Welcome and nice rig by the way.

I could not find anyone in Anchorage that sold steel shims, everyone had aluminum. I found a set on Ebay from 4x4machineshop, shipped to alaska (not everyone does). There's others out there selling steel shims, should not be a problem locating if you live in the lower 48.

 

[72RatCamaro]

Haven't started with my issue yet but I got death wobble. Starts at aprox 42 mph and is gone completly by 44-45. Not that I've ever driven in an earth quake but I think this is what it would feel like.

Yes I think the 36inch swampers have alot to do with my prob.

Thats excatly how mine is...at like 34 mph then gone by 37mph unfortunatly my roads I go on are about a 35mph road.

 

[Hugh Heifer]

Thats excatly how mine is...at like 34 mph then gone by 37mph unfortunately my roads I go on are about a 35mph road.

Mine was so bad I could not drive through it. I rebuilt the entire front end. All my knuckle bearings were completely shot. At the same time I added 4 Runners discs and that did he job. At 35mph I thought I was going to be thrown off the road.