Need help: Jeep is violently rocking when it hits a bump at 60kph

[fuzzylizard]

Hi all,

I realize I haven't been on the forums much in the last few months, but I have a serious problem with my jeep and am looking for some insight before I take it to the garage. Here is the problem:

When I drive down a regular road at 60 and my Jeep hits a bump in the road, it starts to shake or wiggle. This builds up until the jeep is no longer safe to drive. This can take approximately 10-30 seconds. I have to come to a complete stop in order for the shaking to stop. This has been slowly getting worse over the last few weeks. Today it happened 3 times, 3 violent times, before I was out of my neighbourhood.

The shaking can first be felt in the steering wheel and then in the whole jeep.

I realize that is probably a pitiful description of what is going on. I do apologize, I am not a mechanic. Is this simply a case of a wheel being out of alignment or the weighting being off or is there something more serious going on. I have checked the front stabilization bars and they seem to be still attached.

Any ideas and help is most appreciated. Thank you.

Jeep: 2007 Jeep Wrangler Sahara, 31" Tires, 4" life kit (I did not put the lift kit, so I know nothing about it)

[esi]

You sir have a case of Death Wobble.  Check sheel bearing, ball joints and tie rod ends, and track bar for play. Or have someone shack the steering wheel back and forth and look under the front end to see whats moving that shouldn't be.

[mike s]

Try a good quality steering stabilizer, it should dampen any oscillations created. It won't fix worn componets though

[JackstandJohnny]

who put your lift on? was a new track bar used? or a relocation bracket? 

i might not be the best person to ask about this right now as my jeeps wobbling pretty bad, but its not bump related (my jeep hates me)  but 90% of the time death wobble occurs from a track bar not running parallel with your drag link, or loose boshings in the track bar.  'death wobble' is when the axle oscilates at a rapid speed from left to right, so much so that there is no control to the driver.  usually cause by bad track bars etc. wheel bearings/balljoints bad tires etc. will multiply this significantly though.

now on my YJ, i don't have a trac bar so who knows. (hopefully Billy LOL)

[Spinalguy]

try search 'death wobble'
here is one good read...
http://forum.calgaryjeep.com/index.php?topic=11483.0

[fuzzylizard]

Thanks for the advice guys. I have no idea who put the lift kit on as I purchased the Jeep with it already installed. I now have some knowledge when taking the Jeep into the garage. I think the bump thing is just the trigger to start the death wobble. In terms of bumps, I am talking about very small bumps and regular irregularities in the road (small dips, manhole covers, etc).

[fuzzylizard]

Stupid question time, who is Bill and how do I get in touch with him. I was just going to ask for suggestions on who to take the Jeep to. It is still under warranty with the dealership, so I may be able to get them to look at for no cost, but I am not convinced that they will be able to spot or correct the problem if it is with something like the trac bar on the lift kit. On the other hand, I am not sure how having someone else fix it might impact the warranty.

Another question, I am looking at putting 31" tires on the Jeep and storing the 33s that it has right now. The problem is that it doesn't fit in my garage (it is about an inch to tall to fit through the garage door smothly). Right now the roof rubs on the bottom of the door whenever I enter or exit the garage. It is incredibly annoying. I am also reading that using smaller tires can help solve the death wobble problem, so this might kill two birds with one stone.

I am looking at the Goodyear Wrangler DuraTrac tires as a good all purpose road, snow, off-road tire. Anyone know how much they cost and where a good place to purchase them is? I will also need rims since I don't know if they will fit on the rims for my pro comp tires.

[fuzzylizard]

Thanks for the answers. I am located in the north of Calgary, about as far north as you can get and still be in Calgary - way up in Evanscreek, just of Symons Valley road.

As for the warranty, I bought the Jeep from the dealership with the lift kit installed. The previous owner had it installed. Since I purchased the Jeep with the lift installed, they are ignoring it and still working on the Jeep as if it was under warranty (which works out well for me).

I realize that changing the tires won't solve the underlying problem. I was hoping it might lessen it and make make it harder in the future for the problem to pop back up.

There is a reason that I want to take it back to the dealership. The dealership gave the Jeep its 45,000 kilometer maintenance check and tune up about 4 weeks ago. The death wobble only showed up after the tune up. I am thinking that there may be a chance there is something the mechanic didn't tighten or align properly.

Anyone live in the north end of Calgary who would be willing to pop over this weekend and have a look? I realize it is a lot to ask, but it would be appreciated. I am not a mechanic, and although I am thankful for all the advice, I don't fully understand it and wouldn't know what parts are suppose to move and which aren't.

[muffintop]

4 Things to consider:

1) Think of it as cause and effect. Something is causing it... but you have something loose or worn in your suspension that is allowing the effect.

2) Another way to look at it is like a washing machine. If you have an unbalanced load in a washing machine that is not sitting on all 4 feet on bare concrete... it will dance all over the place. Adjust it so it sits on all 4 feet on top of a rubber mat and you have constrained the motion. You may still have vibration (still an unbalanced load) but it wont dance all over the place anymore (death wobble) as you have constrained the motion that "allows" the death wobble to fully develop.

3) If it is violent death wobble... a steering stabilizer wont fix it. Something in your suspension is not constraining the motion (worn bushing, loose bolt, etc).

4) PM "bnine" he will fix your problem.

[fuzzylizard]

4) PM "bnine" he will fix your problem.

Done, and thanks for the suggestions.

[Shearcon79]

I had this problem with my YJ and it ended up being the steering stabalizer.  It was friggen scary!!!  The smallest bump at like 60k and above would send the jeep into a frenzy.

[muffintop]

I am also reading that using smaller tires can help solve the death wobble problem, so this might kill two birds with one stone.

Not necessarily. Rotating mass (heavier or lighter) furthest from the axis of rotation can cause problems if either largely unbalanced or wont stay in balance. You could go to a smaller tire and have the same or worse problem depending on total rotating mass of rim and rubber and whether it can be balanced or stay in balance.

I run completely "unbalanced" beadlocked 35" rubber. After one run... my rims were loaded with mud and my steering stabilizer had actually come off... still... I drove home at various speeds up to about 120kph without any substantial vibration. Reason I got away with it (in my opinion) is that every front end component & bearing on my Jeep are brand new (tight) and wont allow enough movement to develop death wobble.  

What are the 12 scariest words in the english language? Hello... I am a mechanical engineer and I am here to help  

I am looking at the Goodyear Wrangler DuraTrac tires as a good all purpose road, snow, off-road tire. Anyone know how much they cost and where a good place to purchase them is? I will also need rims since I don't know if they will fit on the rims for my pro comp tires.

PM "esi"...

[Rookie]

Done, and thanks for the suggestions.

If Bill can't fit you in pm me and we'll set something up, your kinda on the way home for me

[fuzzylizard]

Well, I talked to Bill and took my Jeep down to his place where he had a look at it. He rebuilt the bushing for the trac bar and the death wobble went away for a few days. And now it is back. So now I have a 4000lbs paper weight for a vehicle.

From what Bill said, my vehicle has been plagued with death wobble long before I bought it.

So now I am not sure what the next move is. I am thinking of going with smaller, lighter tires that sit closer in on the axil and if that doesn't work, then I am thinking of removing as much of the lift kit as is necessary to get rid of this problem. Unless of course, someone out there wants to buy the jeep off me for about $20,000.

Any Rubicon drivers out there looking to upgrade their tires? I would love to do a straight trade, my 35" Pro Comp tires for your stock Rubicon tires. With the way things are going with this Jeep, I need to have a new set this weekend.

To be completely honest, if I had known Jeeps were this much trouble, I would have bought a car. I need this Jeep as my daily drive and right now I am afraid to drive it anywhere. And of course, I don't have the money to go out and buy a second car so I can leave the Jeep in the Garage. (Sorry for the complaining, I am just incredibly frustrated right now)

[muffintop]

Heres my $0.02 CDN.

Have you talked to Bill since the problem came back? Did he suggest upgrading the trackbar to a quality adjustable w/ good rod ends? Did he say anything else was suspect?

If and only if the problem is very consistent... I would try and run a set of "known to be good" stock rims and tires (cant be that hard to borrow) and see what happens. If that cures the problem... you know you have an issue with your 35's and/or rims (i.e. heavy, severely unbalanced, separated, bent or combination thereof). If you cant find some stockers to borrow... how about swapping your existing front <-->back rims & tires to see if problem goes away or changes? Do you have a 35" matching spare?

Also... how about:

1)  Some pics of your rig & front suspension?
2) A few specs/details regarding rim size & type, tire size & type, lift size & brand, km since installed, who installed, how many trouble free km's did you put on till problem started, was anything changed on the Jeep prior to the problem showing up?

I appreciate your frustration... but considering the number of lifted jeeps on the road... this problem is not that common & severe or no one would be driving one. It has to be something with your Jeep... not Jeeps in general.