Death wobble

[deecorpse81]

The other day my truck started the death wobble which someone told me its called, it randomly shakes like its going to fall apart I have to slam on brakes for it to stop and it looks like tire wobbles on driver side when it happens when I looked out window. It happen 4 times coming home first time only 10 miles and it broke my front axle and ripped pout bolt to caliper too. fixed both of them thought it was because broke front axle but no its still doing it. I had some one look at it they said ball joints my ? is would bad ball joints cause it to do the death wobble and feel like its going to fall apart it shakes so bad. I don't have money to take to shop and would like any suggestions what it could be. I put a lot in this truck so far and had it for 3 weeks.

[Doug_Scott]

Chances are your truck is not still in stock configuration. How was the truck lifted? What generally causes this is mismatched angles of front end components.

 

A simple way to see this is this. Take your two front tires, and put a single bar between them that connects to the tie rod end. With the bar parallel to the ground, if you push on one tire, it will push the other tire with no lost motion.

 

Now, make that bar a foot higher on one side only so the bar is now on a large angle to the ground. Push on one tire and the bar will likely not turn the other tire, but will try to raise or lower depending on the side you push on. That is essentially the effect you are getting.

 

By design front end geometry will try to make the wheels try to turn against each other at speed. This is done to make it more stable. Problem is, once you make the changes to front end height, it makes the front end parts stop pushing directly, and starts making the long parts flex. That will make the front end very unstable, and you will get a bad shake if you hit a bump that upsets the suspension enough to start that oscillation.

 

Sometimes a steering stabilizer will hide this effect. It does not fix it, it merely hides it. To fix it properly you need to get the angles of all the components corrected.

 

If truck is not lifted, then you have worn parts, bushings, or bent parts in front end. Should be easily seen, or measured by a wheel alignment machine.

[Halo8]

Sounds Dreadful, I recently read an article that explains that Caster is the angle to which the steering pivot axis is tilted forward or rearward from vertical, as viewed from the side. If the pivot axis is tilted backward (that is, the top pivot is positioned farther rearward than the bottom pivot), then the caster is positive; if it's tilted forward, then the caster is negative. It goes on to compare this to a shopping carts front wheels and how they steer, the tire itself generates a bit of a castering effect due to a phenomenon known as "pneumatic trail," but this effect is much smaller than that created by mechanical castering, so we'll ignore it here). Fortunately, it is possible to create castering by tilting the steering axis in the positive direction. With such an arrangement, the steering axis intersects the ground at a point in front of the tire contact patch, and thus the same effect as seen in the shopping cart casters is achieved.

[Doug_Scott]

Sounds Dreadful, I recently read an article that explains that Caster is the angle to which the steering pivot axis is tilted forward or rearward from vertical, as viewed from the side. If the pivot axis is tilted backward (that is, the top pivot is positioned farther rearward than the bottom pivot), then the caster is positive; if it's tilted forward, then the caster is negative. It goes on to compare this to a shopping carts front wheels and how they steer, the tire itself generates a bit of a castering effect due to a phenomenon known as "pneumatic trail," but this effect is much smaller than that created by mechanical castering, so we'll ignore it here). Fortunately, it is possible to create castering by tilting the steering axis in the positive direction. With such an arrangement, the steering axis intersects the ground at a point in front of the tire contact patch, and thus the same effect as seen in the shopping cart casters is achieved.

 

When GM added the RTS suspension changes to the Monte Carlo in mid 70's, one of the changes was to increase caster(at that time caster numbers were in the 0 to 2 degree +, Monte Carlo wanted +6 degrees). They went so far that they ended having to put steering stabilizers on them to stop the "caster shimmy". If you want to see the effect of caster on steering, go to an empty parking lot and backup. Turn the wheel slightly one way and let go of it. The wheel will continue turning sharper in that direction while moving backwards. The caster is also used to return the wheel to the straight ahead position when going forward.

[deecorpse81]

 

 

 

It has 6in susp lift I drove it from ky to northern mich with now problem and put about 1500 miles altogether on it since I got it and it only started other day it started when I went down a crappy road with all pot holes ive been on horrible dirt road better then this road I was on it was paved too the roads up here are junk every where u go here even if they re did them a few years back they are junk. It looks like tires going to fall off rim when it starts I look out my window and see tire going crazy as hell. I know alignments off since I got it to go straight I have wheel about 2 o'clock or so and steering's very sloppy. When I had it jacked up with both tires up they had no play up and down or side to side. There 35x12.50x15 could a blown belt cause it and how do u check tires that big for blown belt? Ive done so much with this damn truck put new crank and cam sensor full tune up, new front axle now and calipers, and I need 2 tires for back cause there bold as hell. and I just ordered 4 new shocks cause one of the rear ones broke right off a week ago. I went all the way down south to get nice rust free truck and now im paying out my ass for it. I knew it needed 2 tires in rear and front alignment that's all I expected when I bought damn thing. and I have to get fly wheel replaced too one of these days before winter hits. everything looks solid in front nothing broke or loss.

Edited September 6, 2014 by txab

[Jsdirt]

Just because there's no rust doesn't mean it's a new truck. The good part is, at least you'll be able to replace what needs to be replaced without a cutting torch, air chisel, & BFH. Any way you slice it, your still ahead of a payment on a '14 or '15 by a LONG shot.

 

With all the money you save over a monthly payment, you can MAKE that truck brand new with some patience & a will to make it happen.

 

EVERYTHING in that front end is suspect - I would check everything, and replace anything your not sure of. It needs to be CHECKED physically - not just by looking at it. Jack it up by the suspension, get a prybar, and pry up and down on the wheel to check the ball joints. Have a helper try to force the wheel in and out at 3 & 9 o'clock positions while you watch the steering linkage and rod ends. Try to force the wheel diagonally to check bearings. It all needs a thorough checking.

[greg912]

The other day my truck started the death wobble which someone told me its called, it randomly shakes like its going to fall apart I have to slam on brakes for it to stop and it looks like tire wobbles on driver side when it happens when I looked out window. It happen 4 times coming home first time only 10 miles and it broke my front axle and ripped pout bolt to caliper too. fixed both of them thought it was because broke front axle but no its still doing it. I had some one look at it they said ball joints my ? is would bad ball joints cause it to do the death wobble and feel like its going to fall apart it shakes so bad. I don't have money to take to shop and would like any suggestions what it could be. I put a lot in this truck so far and had it for 3 weeks.

Does it almost rip the wheel out of your hand?? I had a ford do this just because a bad steering stabilizer.

 

 

Sent from my iPad using Tapatalk

[daxr]

Ball joints don't cause that, though if they're loose they should be replaced anyway. Typically its either caster is too high, a tire is out of round (see if rotating them changes anything) or more likely you just need a steering stabilzer.

[deecorpse81]

I went down south cause here in northern mich every things junk in mich all rusted out crap I been buying stuff down south for past 12 years 2 s10 blazers and a astro van. What is the caster? don't know what that is. no I don't think it rips wheel out my hand it just shakes horrible and I have to pull off road while slamming on brakes to make it stop. when it happens it look like front tires is about to come of rim like rubber band. the bearings fine on both sides.im getting ready to jack damn thing up again.

[Jsdirt]

I hear you there - same here in MA.

 

Didn't think there was a caster adjustment on our trucks - only camber .... but what do I know ...

 

Camber, looking at the front, is whether the top of the wheel is angled outward, or inward.

 

Here's some pics of alignment terms to help you - click on the pics in the middle: http://www.google.com/search?q=caster+camber+toe

[deecorpse81]

would bad u joint in front shaft cause this? I had someone tell me this.

[MikeNH]

would bad u joint in front shaft cause this? I had someone tell me this.

It might but not all generations of the truck have the front shaft spinning in 2WD. Details on the truck would help.

[deecorpse81]

98 gmc sierra 4x4, 6in susp lift, 35in tires.

[MikeNH]

Pretty sure a 98 the front driveshaft will not be spinning in 2WD.

[Doug_Scott]

Not likely going to be a u-joint. What your friend was likely referring to was if the front axle u-joint starts to seize, when you were in 4wd, and tried to turn a 90 degree corner, the steering wheel will jerk a fair bit while wheels are turned. That is not what you are getting.

 

Suspension lift kits have always made me uneasy. Body lifts do not have the same issues.

 

There should be a lot of information on the condition you are experiencing on the net. You need to find out what lift kit was used, and then need to search for others with the same kit having the same issue. A steering stabilizer may hide the issue, but it will not FIX the issue.

 

You likely will not be able to move the parts by hand to see what the issue is, the parts are not actually loose, they are flexing due to the angles. You will also find that driving on smooth roads will not cause the oscillation to start, it usually takes a good bump on one wheel to set it off. Once it starts, the only way to stop it is to brake hard (as you have already discovered), if you don't stop it, it will only get worse, and will likely end up with broken parts, and depending on how fast you are going when it breaks those parts, it may correct the issue for you by writing the truck off.

 

If it were me, I would find out what lift kit was used, research how that kit is supposed to be installed, compared to how it is installed, and search for others with same hardware having same issue. I have seen a tv show recently on lifting trucks, and one dealt specifically with this issue and how to prevent it. I do not recall which one though. It was in the PowerBlock series of programs on Sunday morning here.