UCA/LCA Measurements

[CBJeeper]

I searched this topic and found some information on setting UCA and LCA lengths but am still left wanting more. I have a 90 Wagoneer Limited on which I am installing a BDS 3" lift with new spring packs in the rear. I am also installing Core 4x4 upper and lower adjustable control arms. I read that some use 16 inches for the lowers and 16 3/4 for the uppers. Does the height of the lift impact the CA lengths? Can anyone provide initial measurement guidance please?

 

[75SV1]

I have for a 3" lift LCA 16.09, UCA 14.92

 

[CBJeeper]

I have for a 3" lift LCA 16.09, UCA 14.92

Much appreciated!

 

[Tim_MN]

These numbers are a starting point, adjust as required.

 

[CBJeeper]

I just had Zeus Offroad install Rough Country's 3" lift. If I understand this correctly, as the Jeep is lifted, the Axle rotates a bit resulting in the need for either longer Lower Control Arms or shims to increase their effective length, OR, equivalent changes in UCA length. Zeus installed Rough Country recommended LCA's intended for their 3" Lift which they also installed. Zeus Offroad, located in Burnsville MN, did a great job. And No, I am not a stock holder, but they sure seem to know their business.

The lift allowed me to fix a couple worn out suspension parts, provide better under-body access, and adjust the caster portion of the alignment other garages kept avoiding while recommending adjustable control arms. But the overall result was a better ride, decreased road shock transfer to steering, better overall stability, and less bump steer and wind gust effects. But that's not the answer to your question. The difference in length bolt center to bolt center between the stock LCA's and RC 3" Lift LCA's was less than an inch without having them in front of me. But wouldn't the Core 4x4 adjustable's provide that much adjustability for an alignment shop to get it right? To be honest, from the experience with Zeus, I will undoubtedly think twice before taking the jeep to another neighborhood car garage again. Life is too short...

Ues, the Core 4x4 arms will provide all the adjustment needed. My intent is to get the setup as close as possible and then let the allignment shop dial it in.

 

[CBJeeper]

View attachment 11773

This is perfect. Thank you for sharing!

 

[Sunset]

These numbers are a starting point, adjust as required.



View attachment 11773

Quick question, do those lengths get affected by the shims on the lca? I have core 4x4 acas and no longer have the shims or the the bracket they sit on so for example 3 inch lift needs 16 inches on the lca but I don’t have the shims so does the length change? And does the bolt go all the way to the rear of the eyelet or all the way forward?

 

[Tim_MN]

The shims may be optional, but I doubt the #7 clevis brackets are. I don't see how you are going to keep the control arm bolt from sliding all around in the slot without the clevis or something similar.

The chart is a starting point, adjust as necessary.

When I installed control arm drop brackets, I moved the shims and clevis brackets into the control arm drop brackets.

 

[75SV1]

I went with ZJ type control arm brackets on the axle. So, the bracket on the body stays fixed. So, you could weld on some washers, to create a 'fixed' location. Then adjust the Core LCAs. I would set it to the rear. I would think most stress or shocking forces would be towards the rear. I do have CORE Stage 1's. The lower control arm brackets I used are Rubicon Express. I do have a set from TNT or another place. A bit beefier. To be used on another project.

 

[Ol Blue]

Ues, the Core 4x4 arms will provide all the adjustment needed. My intent is to get the setup as close as possible and then let the allignment shop dial it in.

Just FYI alignment shops (at least the ones I've been to) generally won't adjust your control arms as part of the alignment package since this was not an adjustable from the factory on the XJ. They will charge you extra labor to change the control arm lengths. Kind of a pain. What I did was buy the unlimited 3 year alignment package from Goodyear and make the control arm adjustments myself and then go to the shop for "an alignment" when all I really needed was the printout of the caster angle.