Thanks to you guys for your feedback and suggestions in my previous threads. I feel as though I'm really close to getting this figured out. Based on some more research and testing/rocking of my JKU, I think the sound that I'm hearing is the rear (likely driver's side) coil spring compressing at an oblique angle and contacting my trackbar. That leaves me with a few questions about the lovely, wonderful RC 3.25" lift I didn't install.

1.) As you can see in the picture below, the lift has shifted the angle of my axle downward, causing the spring perches to rotate back and twist the springs. Should I simply install a correction wedge for the rear and hope that solves the issue?
2.) It looks like RC uses the same springs in their lifts (2.5") and in this case just includes a .75" coil spring spacers for all four corners. Would there be a benefit with replacing these with a higher quality spring that doesn't require a spacer and then use a correction wedge?
3.) Or a combination of the options above and buy adjustable rear control arms, correct that pinion angle and either keep the RC 2.5" springs with spacers, or go whole hog and throw in quality full length replacement coils?

I know eventually I'll be done fixing issues that came from the previous owner's cheap lift kit. There's no problem opening up the checkbook to make it happen, but I'd like to hedge my bets and get some input from someone who knows better than me. Any advice is appreciated!

Here's a pretty recent picture of the setup. The angle isn't great for showing it, but there's a pretty decent angle to the coil springs on the rear axle.

 

You have a couple different options...

1) my least favorite but the easiest is to install some correction wedges, this is a simple insert under the spring that will raise the back end of the spring so you’ll have a better angle. It’s my least favorite because I prefer a solid perch welded to the axle that is permanent.

2) cut the original spring perch and rotate them or just cut the rear of the perch and lift it, then weld into place. If you can’t do this then a shop won’t charge too much to do that. The down side is that if you ever change your suspension your springs may not be aligned properly again. Do this if you don’t plan to make any further changes.

3) new rear control arms to lower your rear pinion angle which will reduce the bow in your springs.

I had this issue a few months ago and I just rotated my pinion angle down a bit. Eventually I’ll get new spring perched and weld them into place but I want to wait for that till I get new springs so I can make the perches right for the springs I’m going to use.

The hard part about modifying the suspension is that you’re going to have to figure out a work around for many things. A simple spring and shock lift with non adjustable control arms will give you issues like you have. I don’t think I’ll ever recommend anyone lifting a Jeep unless all control arms and track bars are adjustable for this reason. You’re changing geometry on everything when lifting and axle placement is impossible to get right unless you can adjust the control arms. Some people use drop brackets and unless your control arms are perfect for that bracket you still have axle placement issues.

 

Sv_dude....gotta do something about the new avatar orientation!

 

Thank you kindly for the great feedback. The ship has already sailed on reverting this Jeep to stock (which I had considered), but I'm in too deep now. At this point, I'm considered just installing adjustable control arms all around. Do you have a set or manufacturer you recommend? I know the cost will be steep, but I'd like a good balance of quality and value.

The other thing is, I've already installed geometry correction brackets. Should I take them off, or is there any advantage to keeping them on with adjustable front control arms?

 

haha, not sure why but the forum changed the orientation. I’ll play with it later.

I use metalcloak control arms and track bars. Their bushings have great road manners and lots of flex. There may be other good brands out there but I honestly feel like metalcloak is the winner. They have a great product and their customer service is top notch!

As for the brackets, I can’t really make a great suggestion other than I think they would hinder ground clearance when on the trails. I don’t use them on my rig and so far haven’t seen a need for them.

 

The main drawback to using control arm brackets in addition to adjustable control arms is loss of clearance as mentioned. The brackets actually position the front control arms at a more level angle which is better for pavement driving. At that point, adjustable arms is kinda an after thought unless you 1) need clearance for off road purposes, or 2) can't adjust caster enough with just the bracket options. The rear is a different story, but I'd just mention as you lower the rear pinion to improve the spring issue, you steepen the angle the rear DS runs. On a 4dr, the rear DS is a bit more forgiving as it has CV joint on each end.

We all have differing opinions. In this particular situation where we're talking rear TB/coil interference, I'd opt for $20 wedges you throw under the springs. If we were talking a different situation, i'd opt for a different solution.

 

Thanks again for all the great info.

At this time, I'm deciding between the JKS u-bolt spring perches and/or a set of upper and lower adjustable control arms. It looks like MetalCloak makes a rear control arm geometry bracket, but you need adjustable arms for it anyway. Plus ot appears to be for 4"+ lifts.

Here's pictures of my rear control arms as they currently are, plus the driveshaft. I was hoping for an opinion on my pinion angle, since that might determine the route I take.

 

I’m not a fan of u-bolts on the axle. They just give rocks or other stuff on the trail something to hit. And at $190...!!! Wow! You’re better off going with resharps advice on a $20 wedge. If you get adjustable control arms then you can just tilt your pinion angle down a tad and you won’t need to do anything. Your pinion angle looks fine too by the way, but even angling it down a little with control arms will be good too.

 

Yup, one or the other, but both is redundant for your set up. The upper arms will allow you to tilt the pinion down and should provide the clearance you need if you go that route.

The issue most of us run into is pushing the axle back with a full set of rear control arms. This gets the axle spring perches much more out of alignment to where repositioning the perch is the real solution.

On a side note, I'm surprised the boot at the spines on that rear DS isn't shredded yet. The silly evap skid right next to it usually chews that up quickly. Have you or the previous owner repositioned that over a bit? Maybe the jeep hasn't seen much time off road? If you want a fun afternoon task one day, you can remove that rear DS and flip it around. Since it has CV joints on both ends it can be mounted in either direction. Oriented the other way gets the boot further away from that evap skid. Tereflex also has a video out there showing how to easily move the skid just a bit further away from it.

 

I think with the options I have, adjustable rear control arms are a good choice to correct pinion angle. From what I've read, it can also help with rear axle dog tracking...which is something I feel I'm experiencing. Mostly, I didn't want to go to the expense and trouble of installing them only to find that it negatively affected my pinion angle from where it's at right now.

Then, I could probably assess the situation regarding the rear spring bulge and possibly get some correction wedges if necessary. Also, about the adjustable rear control arms, sorry if you already explained it, but I could get away with getting adjustable uppers with the stock lowers? Or would there be any benefit to just getting upper and lower adjustable rears?

Also, I haven't touched that evap skid plate, but thanks for the headsup. I can't say whether the PO messed with it, but based on how straight everything looks underneath the rig, I'm guessing it's seen very little if any offroading. I'll see if I can make sure that plate doesn't interfere with the boot, though.