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Advice Needed – Adjustable UCAs & LCAs on RE 3.5” Lift

beasticles

NAXJA Forum User
Location
Northern VA
I started installing my IRO adjustable upper control arms (I also bought lower control arms from IRO as well, just haven’t installed yet) on Sunday and continued the process last night (had to make a trip to Lowe’s yesterday after work to buy new hardware for the UCA bolts – whoever decided using flag bolts on the UCAs for our Jeep XJs was a good idea a GENIUS [sarcasm].

With the RE 3.5 lift I netted a little over 4” of lift in the front and about 4.5” lift in the rear. I am also running Rough Country LCA drop brackets with stock LCAs.

I started with the uppers first since I figured they would be more of a pain and I wanted to get the hard part done first (I was right). Using the UCA and LCA length chart I found here: http://www.xjtalk.com/showthread.php?t=9520 I adjusted my uppers to right about 16.5” (a tad longer than the chart shows for a 4" lift but it looked better than 16 3/8" on my pinion) which made a dramatic improvement on my pinion angle.

How does my caster look?

I did a mock up (put the tires back on and gently lowered the jeep onto the tires to check pinion angle and caster on the ground – it looks about right – right around 2 or 3* –which I know is a little low - should be closer to 5-7*, correct?). I am thinking of buttoning it back up with the stock LCAs and drop brackets and seeing how it rides. My tires are actually perfectly placed in my wheel wells right now – if I pushed the axle farther forward by installing the adjustable LCAs – my tire would likely be too far forward in the wheel well. I will likely install them since I have them and dial them in to the shortest setting which is 16" - my stock UCAs are 15 3/4")

Can you guys take a look and let me know what you think? I feel like with all suspension stuff it's trial and error. But should I be concerned with the caster being too low?

15401144705_481c4c4a89_b.jpg


Once I rotated my axle with the adjustable UCAs I also see that my sway bar is impacting my springs. The RE 3.5 kit came with longer 6” sway bar end links. I actually think slightly shorter end links would solve my problem by pull the sway bar down- and away from the coil springs. Probably need about 5” end links – does that sound right to you guys? Just so you know this is not an issue of the axle not being centered - the springs are lined up evenly in relation to the unibody frame on both sides.

Another pic of the sway bar hitting the coils:

15397962551_68710c97c5_b.jpg
 
I think he meant that you're gonna need longer disconnects. Maybe?


Not to hijack the thread, but I just put the same lift on my 2000 and I'm fighting some pretty bad bumpsteer/death wobble. Upgraded my track bar, thinking that was the issue . . . NOPE.

NOW I'm reading way, way too much information about how it's probably my stock control arms throwing off my caster angle. Crud! So I guess this means I need new control arms. Unfortunately, money is an issue at this point.

If a guy were going to replace only one set of control arms to correct bumpsteer/deatj wobble, which should he do? Uppers or lowers? Anyone have a definite answer? I've read people arguing for uppers and I've read people arguing for lowers. Now I'm more confused than ever.

Help me NAXJA forum, you're my only hope!
 
I think he meant that you're gonna need longer disconnects. Maybe?


Not to hijack the thread, but I just put the same lift on my 2000 and I'm fighting some pretty bad bumpsteer/death wobble. Upgraded my track bar, thinking that was the issue . . . NOPE.

NOW I'm reading way, way too much information about how it's probably my stock control arms throwing off my caster angle. Crud! So I guess this means I need new control arms. Unfortunately, money is an issue at this point.

If a guy were going to replace only one set of control arms to correct bumpsteer/deatj wobble, which should he do? Uppers or lowers? Anyone have a definite answer? I've read people arguing for uppers and I've read people arguing for lowers. Now I'm more confused than ever.

Help me NAXJA forum, you're my only hope!

Well right now you can see I only have the UCAs installed with CADs for the LCAs (still with stock LCAs installed) and I am able to easily adjust my caster and pinion. It almost looks like I don't even need to extend the lowers right now.

I bought the adjustable LCAs from IRO as well because I figured I might need them in addition to UCAs based on everything I have read. My adjustable IRO CAs were $340 shipped for all four and they are beefy and good quality.

You have to keep in mind though I have CADs which I bought used for $100 from a local guy. If you factor that cost in (CADs are like $160 new) you may be better off just buying adjustable UCAs and LCAs from IRO.

I will post up once I button everything back up and if I need to install the lowers to extend the axle out more.
 
Pinion angle is more important than caster angle. You may have to compromise on both to get decent road manners and no front drive line vibrations.

You need longer sway bar links/disconnects or sway bar relocation brackets.
 
INot to hijack the thread, but I just put the same lift on my 2000 and I'm fighting some pretty bad bumpsteer/death wobble. Upgraded my track bar, thinking that was the issue . . . NOPE.

NOW I'm reading way, way too much information about how it's probably my stock control arms throwing off my caster angle. Crud! So I guess this means I need new control arms. Unfortunately, money is an issue at this point.

If a guy were going to replace only one set of control arms to correct bumpsteer/deatj wobble, which should he do? Uppers or lowers? Anyone have a definite answer? I've read people arguing for uppers and I've read people arguing for lowers. Now I'm more confused than ever.

Help me NAXJA forum, you're my only hope!


Death Wobble is caused by the same issues, lifted or stock, worn or damaged suspension/steering components.

Find and study the Control Arm Length Chart. Most lift kits include longer lower Control Arms.
 
Your sway bar is installed correctly, don't flip it. Imagine a line from the sway bar bushing through the end of it. That line should be about +15deg. You need longer links, sway bar drop brackets or shorter coils. I'd get some JKS discos.
 
Your sway bar is installed correctly, don't flip it. Imagine a line from the sway bar bushing through the end of it. That line should be about +15deg. You need longer links, sway bar drop brackets or shorter coils. I'd get some JKS discos.

Thanks. Yeah I am going to plunk down the cash for adjustable discos from JKS. This Jeep has exacted it's pound of flesh from me long ago...
 
The thickness of the flat stock used in that writeup for the upper mount bothers me. Looks like 1/16". For reference JKS uses around 1/8" for theirs.

Good call. I'll be using the adapter bracket you see in my pics from the first post, which are Rubicon Express and are more beefy than the homebrew adapters I linked to. I just needed the longer endlinks, they should mesh well with my existing hardware from the RE lift.
 
Quick update - I installed the WJ rear endlinks on the sway bar last night (worked like a charm to push the sway bar up and away from the coil springs), buttoned up the adjustable UCAs and put the front driveshaft back on, and took it for a short spin around the neighborhood. I don't want to jinx myself but the ride was SMOOTH AS BUTTER and knock on wood - no death wobble. I have yet to take it above 40mph to test for squirreliness or death wobble at higher speeds, so I am keeping the celebratory beer on ice until I do that. I have to replace to stripped studs on the driver side front hub before I drive it any more.

Basically the set up I went with is as follows:

-16.5" for the adjustable upper control arms
-stock 15 3/4" fixed LCAs with Rough Country control arm drop brackets
-pinion angle is about perfect - just a tad below 0*

I haven't installed the adjustable LCAs at this point. If I don't have to I won't - the stock arm bushings are quiet and seem to work well with the CADs.
 
For pounding the pavement, stock LCA's will work. I would definitely install the the aftermarket LCA's if you plan on offroading.
Just set them to the same length as the stockers, replace one side at a time. Will help if park brake on and front wheels chocked.
 
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