Suspension and Wobbles: Post Project Questions

[Jedeye]

I come before thee but a humble servant. I had to replace my leaf springs on my '96 XJ. I replaced them with Old Man Emu CS033RB lift springs. I also replaced the rear shocks that were shot with some Skyjacker H7018 shocks.

Unrelated to the rear suspension stuff but I had to replace my steering stabilizer since it was also worn out. I used a Rancho RS5401 Steering Stabilizer.

I decided to have my mechanic shop do all the labor since I didn't have the necessary tools and I am not living at home. Plus I didn't want to tackle the rear leafs after reading so much about it on here. Anyway, as with any XJ project, more problems have arisen and I need advice.

1. I had the mechanic take out the 3rd leaf in order to reduce the lift on the rear. There is a 2.25 in spacer in the front and there WAS a 1.25in block in the back. I got rid of the rear block by using lift leafs as opposed to factory leafs. I removed the 3rd leaf as per the manufacturer's instructions to get closer to the 2.25 inch of the front. They said out of the box the leafs will give closer to 3-4 on a stock/light weight jeep. So removing the 3rd leaf will bring it down some. My concern is that my rear is now about 1 inch higher than the front. In other words, The leafs gave me about 3 inches or a little more in the back. Will the leafs settle that much to match the front? I have a rear mount spare tire and about a 100 pound storage system in the back so I am assuming that will help. Or do I now need to replace my stock shocks and 2.25 inch spacer in the front with a 2.5-3 inch spacer and new shocks? I am concerned the higher rear is going to affect my performance (See question 2)


2. I have the shakes. Well not me really but my XJ. AKA death wobbles. I am not new to this monster though as when I bought the jeep it had some pretty worn mud tires. The more worn they got, the worse the wobbles got. When I replaced the tires they disappeared. I am about to move across state so I wanted my jeep checked out. My mechanic said everything looked tight and good with the front suspension except my steering stabilizer needed to be replaced. But everything else seemed good. I mentioned that I had just started to get a little bit of wobbles and He said the stabilizer being worn out could have affected that a little. After we replaced the leafs and the stabilizer, the wobbles are a little worse. The mechanic discovered this when he drove it after doing all the work. He went back to the shop and checked everything that he said could possibly cause those wobbles and he has arrived to two possible causes: Either my tires being worn are causing it or the lifted rear end being higher is putting more weight on whatever is causing the problem. Otherwise everything else seems tight. Or some combination of both worn tires and rear weight. Any ideas?


Sorry to put so much in one thread but I think these are related. What do y’all think?

 

[XJ_Rudolph]

Do you have any lift on the front? Bad track bar angle can cause death wobble, as well as a loose track bar or track bar bracket. I would look at those two things first to make sure its all tight and the track bar is more parallel to the ground than vertical.

 

[Jedeye]

Do you have any lift on the front? Bad track bar angle can cause death wobble, as well as a loose track bar or track bar bracket. I would look at those two things first to make sure its all tight and the track bar is more parallel to the ground than vertical.

Yes I said in the OP that there is a 2.25inch spacer in the front. Everything is good and tight under there as well.

 

[XJ_Rudolph]

hmmmm yea that lift shouldn't be enough to cause the track bar to not be at the right angle. Next maybe check tierod ends to make sure they are not bent and make sure the bushings dont have play (do this by having the key in the car and have an assistant turn the wheel back and forth while you watch the bushings).

After all that I would try and put your frame on jack stands and have an assistant shake the heck out of the axle to see if theres play in any control arms.

 

[Jedeye]

Hahaha with all due respect, did you read my OP? We checked all the moving parts of the front steering and suspension. Like I have said, everything is good and tight. So the solution is unlikely to be any of the usual death wobble repairs.

 

[IslanderOffRoad]

Hahaha with all due respect, did you read my OP? We checked all the moving parts of the front steering and suspension. Like I have said, everything is good and tight. So the solution is unlikely to be any of the usual death wobble repairs.

We in your post referring to your mechanic, correct?

Have you checked yourself? Chasing DW isn't exactly profitable, he may have wanted the jeep out of the shop.

The rear will settle.

Steering stabilizers don't fix DW, they mask it.

Next step is to get under the front end and check everything. In your case I'm thinking ball joints or uca bushings would be good places to start looking. How many miles are on the jeep?

 

[831_xj]

Start with alignment. If it's dead on to 1/8" in you should be ok.. if it still wobbles. Toe it OUT a bit see if that helps.

 

[iluv83vettes]

Start with alignment. If it's dead on to 1/8" in you should be ok.. if it still wobbles. Toe it OUT a bit see if that helps.

TOE IN IS MEASURED IN DEGREES NOT INCHES

 

[blondejoncherokee]

I bet either all of the below or at least some are the issue :
Trackbar ends
Loose trwckbar bracket
Control arm joints
Tres
Ball joints
Tire balance
Axle u joints


You need to put a breaker bar on every bolt and make
Sure they are all super tight.

99/100 times its the trackbar.

Shop sounds sketchy if they say the higher rear could cause DW. I wouldnt ever
Go back there.

 

[GordoSmasho]

Hight changes in the rear end will change the caster in the front end. Caster is measured in relation to the ground. So if the angle of the vehicle changes (lift of the rear end increases or decreases) then the angle of castor changes. That has the potential to cause enough change to instigate DW. It can definitely be a contributing factor so your mechanic isnt completely blowing smoke. However, if the mechanic is not familiar with aftermarket kits or adjusting one, it may be better to learn how to do it your self or find another shop to check and adjust your alignment.

I would start with some measurements and go from there. Or take it to a 4wp or somewhere that is knowledgable with aftermarket lift alignments.

 

[Jedeye]

Well guys my predictions were correct. I got new tires yesterday and the wobble is gone. I can feel where it barely wants to do it around 52 mph which is where it did it before. But honestly its so subtle I may be imagining it even being there haha. Now the plan is to wait and see how much the rear settles since it is still a little higher than the front.

I went ahead an trimmed the back corner of the front fender and was able to fit 265/75/R16s under there (running wrangler wheels). So in all my spending on the suspension at least I was able to move up a tire size And dangit guys i've got the fever. Now I want to do everything to my Jeep. Thanks for the help everyone!

 

[GordoSmasho]

You should deffinately check your alignment. Missalignment and bad suspension joints can ruin tires in short order. It is very easy to do your own alignment in the driveway with a few tools and a tape measure and angle finder.