Weird Scary Bouncing!!!!

allanmuro

New member
Hello everyone. I just bought me a used 2007 JK. Has 4" lift and 325/70-R17 tires. I really don't know anything about suspension or mechanics. Since I got it I have been experiencing some wierd hard bouncing/rocking at certain points while driving. It happens whenever I pass let's say 30 mph and only if I go over uneven surfaces. And not alwys at certain times only. It feels like the whole front starts shaking and it only stops doing that if I apply the brakes almost to the point of stoping. It is kind of scary sometimes. If I just decrease the speed it still bounces-rocks. I went to a mechanic and he said the shocks were busted so I purchased some Ranchos 9000 XL fo rthe front and back. We installed them and it still does this. Since there are not really professional mechanics here where I live I want to ask if anyone can help me pointing me the right direction in resolving this matter. Thank you in advance. 8)
 

A jk with death wobble? Haven't heard of one yet, but the shaking until stopping is one of the symptoms of death wobble. Search for death wobble in tj's and see if it's similar to what you experience. The cure for it should be the same too.
 
u joints
loose brake calipers
warped rotors
tires out of balance
wheels not tightend
air presure not same in all 4 tires
shall I go on
its always the simple things we overlook:?|
 
You will need to check all of the previous mentioned items, but I recommend focusing from the simple to the more complicated... tire pressure OK ---> check alignment (this is a classic symptom of the front wheel alignment being out of whack) --->> next check the tie rod bushings - if there is play in them you'll have this problem also. The JK isn't that old so most of the major items should be OK.

One simple check to do is raise the front end and check the front wheels for play by holding the top and bottom of a front tire and see if you can move it back and forth. If you can, you have to replace the front end components where the play is - this will usually be worn front universal joints but unless you have over a 100k miles on the JK I would doubt that they need replacing.

the good news is that the front end of the Jeep is fairly simple and the component list is limited. While having the alignment checked, it will be obvious if the tie rod ends or the drag link bushings are worn - again, these are items that are unlikely until a vehicle is older. Also, the sway bar link and / or the stabilizer cushion may be worn or the sway bar may be bent - this is a possibility if the JK ever hit a rock.
 
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I finally got my DW fixed on my TJ.New track bar and new tie rod.
 
you are running a 36in tire thats just shy of 13in wide. do you have a steering stablizer?? i think i had what they call the tj death wobble, it turned out to be a worn out bushing that connects the stablizer and the track bar to the jeep close to the axle. it was definately scary running down the road.
 
Thank you all!!!!!!!! Will do some check ups and adjustments based on this answers/pointers and will let you know the outcome. Have a great day to you all. Peace. 8)
 

Sorry to sound to ignorant. How can I tell what kind of wheel off set am I running?? Also what will the best tire pressure be for my tires?? and lastly, How do I make sure my axle tracking is centered??? ANd yes I do have a steering stabilizer. It is the OEM one.
 
you are running a 36in tire thats just shy of 13in wide. do you have a steering stablizer?? i think i had what they call the tj death wobble, it turned out to be a worn out bushing that connects the stablizer and the track bar to the jeep close to the axle. it was definately scary running down the road.

If everything is up to spec, he should not have DW even without a stabilizer. A stabilizer helps hide the symptoms from other problems, but it does not fix the problems...

Sorry to sound to ignorant. How can I tell what kind of wheel off set am I running?? Also what will the best tire pressure be for my tires?? and lastly, How do I make sure my axle tracking is centered??? ANd yes I do have a steering stabilizer. It is the OEM one.

LKay the wheel flat on the ground, and measure the distance from the lip of the rim to the wheel mounting surface. This is easier to do if you have the tire off the wheel (then use a traight piece of metal or wood and measure), but you can always eye-ball it...
 
Did I miss how many miles were on it? How long did the vehicle sit? Flat spots in tires will produce the bouncing.
 

The jeep has 21,384 Miles logged in. As far as I know it was on the lot sitting there at least for like 6 months. If this is what u mean by how long did the vehicle sit. Cheers everyone. 8)
 
But if the tires are radials, it should not flat spot, right? Besides, it does not happen all the time, and it starts at about 30 mph but remains until almost stopped; I would imagine (no personal experience here) that a flat spot will be felt always regardless of speed until the flt spot smooths out...
 
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