Here's the deal: 2000 XJ and I'm running a Zone 4.5 inch lift with 33's. The lift came with new LCA's which are installed, but still running factory UCA's. I am also running a JKS adjustable track bar. Alignment has been done by professionals, maybe in name only. I have done the Durango steering box swap, and replaced the steering box brace/spacer with a JCR piece. In addition I have also upgraded to an aftermarket steering linkage (don't remeber who's) with a dropped pitman arm I have front driveline vibes, and I know this because I removed the front drive shaft and the vibrations diminished substantially. I am also running a TC drop of about .75 inches. Running an SYE and new rear drive shaft.

I have bump steer like a champ! The problem is my caster is wrong. By how much I am unsure.

I have done some research and have found that caster shims are available. These shims are placed in the LCA box but from what I can gather, that will only increase my pinion angle. If you are looking at the axle from the drivers side, the pinion is rotated towards 6 o'clock. Don't freak out, its not pointing at 6 it is just rotated towards 6.

My question is what is the corrective action that should be followed? What measurements need to be taken to provide you all with the information that you need to better answer the question?

This is a daily driver and I commute about 100 miles a day, so on road manners are a must! Sorry for the long post.

Oh and the Jeep is Blue if that makes a difference...

 

if you have an SYE, getting rid of the T-case drop will help with front driveline vibes. As for the bump steer. Make sure you track bar and drag link are at the same angles, your axle centered, and your caster is correct.

 

Your caster should have been adjusted when you had your alignment done... Yes, as you change to correct your caster you will also be changing your pinion angle at the same time. Like already said, ditch the t case drop too.

Take a picture of your steering linkages strait on from the front. Make sure you capture all the way from tire to tire. This will help is assess the possible changes needed done to the steering angles

 

Thanks for the reply.

The T-case drop is to help eliminate the rear drive line vibes I was getting. I know it's peculiar, but even with a SYE and new DS I still had vibes. Track bar and drag link are running at the same angle within a couple of degrees of each other, and the axle is centered. I know the caster is off, I am trying to figure out the best way to correct the caster angle. Do I use adjustable uppers, or adjustable lowers or paint the jeep. The last part is a joke. I hate that I have to explain that last part but there is no sarcasm font.

 

Shim your rear axle so that the pinion points at the tcase.

 

I guess I need a tutorial on how to upload photos to this forum. Anybody got any clues?

 

Exactly. The reason you were still getting rear driveline vibes is because your rear pinion needs to point strait towards the double cardon joint on t case output. Remove the t case drop then do this.

Then take your Jeep to a shop and tell them to give you a FULL front end alignment. Not just toe in and toe out. They will have the shims and align everything for you. You should have plenty of adjustment there for them to do this. THe lower control arms Zone sells arent adjustable?

 

Agreed on the rear drive line vibrations. I have not had time to determine the shims needed to correct rear vibrations, the T-case drop works for now, although not permanent solution.

I'll take recommendations for degree shims on a 4.5 inch lift if you got em though.

I thought I was getting a FULL front end alignment initially. Mistake on my part. There is semi local (1 hour away)off road shop up the road, I will take it to them at this point for alignment.

My avatar was the quickest way that I could find to upload photo of the front suspension. In addition I added a couple of photos in an album under my profile info.

And no, Zone's LCA's are NOT adjustable.

 

Is there a need for adjustable UCA's to correct the caster issue?

And is it just me, or do I not see my own avatar photo...?

 

Yes adjustable uppers will help correct the pinion angle and caster.
based on your current setup that would be the best thing. Shimming the lowers will only make things worse.

No dont see the picture.

 

Thanks for the input SDC!

Is my assumption correct that the shims will just increase or decrease, depending how you look at it, the caster/pinion angle that i have?

 

check out that avatar now mother B*****s

 

Shims in the lowers will push the control arms out making them longer rotating the pinion yoke down.

You need to find a happy middle ground between caster and pinion angle.

 

He most likely already has shims in there though. Probably upgraded to the aftermarket control arms which were longer (too long) and now he needs to remove some of those shims.

 

Man, I wish you were correct, but there are no shims.

Kinda thought (and hoping) you would chime in on control arm recommendations, and rear shim recommendations.