control arms?

hey I have a 4.5 rc x series lift on my jeep and it came with adjustable upper and lower control arms! any way it said to set them at 15.5 for the upper and 16.5 for the lower wich is what I set it at! any way I had it at the alliment shop today and they told me I need to shorten up the left front lower arm to get my rig to drive straight something to do with caber/caster! has any one ran into this problem and what legnth do you guys have your a arms set at with a 4.5 lift thanks!

The upper would adjust caster. I would think something is up if the two uppers and the Two lowers are the same then you caster should be the same on both sides...

there is something dreadfully wrong if you need to adjust one side differently than the other.

Depending on how things were aligned in the factory, your jeep may have shims behind the lower control arms. If yours did, did you reinstall one side and not the other?

16.5" is a good place to start. remember though, 16.5" is in addition to those shims, if your jeep had them.

Also, the factory caster tolerances were pretty loose when they welded the C's onto the front axle. depending on the axle, it could be -1/2" or +3/4", or anywhere in between. In other words, if you swapped axles also, then you may as well throw everything out the window and just rely on the alignment tool.

slcpunk74 said:

The upper would adjust caster. I would think something is up if the two uppers and the Two lowers are the same then you caster should be the same on both sides...

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both upper and lower arms adjust caster.... and on a 4.5" lift, I would want to keep the uppers @ 15" eye to eye, which is stock length.

The lowers have all the adjustments from the factory.

Just a piece of useless knowledge here, but 1/4" of lower arm length makes a huge difference in the alignment of an XJ.

Its difference between white knuckling steering at 35mph, to handling smoothly at 90mph.

If in fact the lift did net 4.5 inches of lift.i would start with 15" on the uca's and 16.33-16.5 on the lca's.problem is most lifts net more than advertised,so do the dirty measuring method and find out what heigth your truly at. if the lift netted 5' of lift i would set the uca's at 15 1/4" and lca's at 16.5 or 16.6 to start.

moneypit_k5 said:

both upper and lower arms adjust caster...

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True but if you wanted to keep your wheelbase the same then you would set the lowers for wheelbase and adjust uppers for caster... If you have a fully adjustable set the why not? Then again I guess your driveshaft length could aslo play into this scenario too...

my lift has only been on for two weeks now and it gave me 6.25 from the start I will try to measure to see if it has settled yet!

If my memory serves, RC lift springs are the same part as rustys lift springs. i know rustys springs dont settle out. last pair I had, sat a hair over 5" 3 years after I installed them.