Adjusting Control Arms for length?

Joseph Humphrey · 09-16-2005, 08:53 PM

i have a noob question and though i would ask it here rather than at NAGCA...

i have a set of JKS Adjustable arms on Kevins 3.5" lift with 31's. i was our driving around our last FTX Site and when the rear end flexed, the tire grabbed the front of the wheel well. i need to push the rear axel back, but my question is how far and can i just extend all 4 arms the same additional distance over stock and not have a problem, or is there a little bit of math involved with upper to lower ratios...?

thanks for helping me out.

**Texas ZJ1** · 09-16-2005, 09:22 PM

These are the measurements for what I'm running. They can be a starting measurement for you.

Now, I'm running RE stuff so there will be some differences but, you can tell from the lengths that I'm still running the stock driveshafts.

Hunter

My control arm measurements are:

all four lowers on mine are at 17 1/2
front uppers are 16 1/2
rear uppers are 14 1/2

Meerkat · 09-16-2005, 10:08 PM

The key element that affects what length you set your top control arms at is the pivot angle on your driveshaft. You should have measured this angle before installing your lift, that way, all you have to do (after installing the adjustables) would be to adjust them out until the angle at the pinion is correct.
All is not lost though. Check into your FSM to find the stock values and go from there.

HTH

Joseph Humphrey · 09-17-2005, 01:03 PM

thanks for the help. unfortunately when i got the lift, i did not have the time to install it myself and had to take it to a shop to have it done...

i was looking through the Haynes and Chiltons manuals that i have, and i really did not see anything about what angle the drive shaft should be stiiing at. i really don't have any problems with angularity right now, so can i just measure what i have and "try" to keep it the same?

i would like to push my back axle out about 1". can i just lengthen them all the same?

thanks again.

**Texas ZJ1** · 09-17-2005, 06:13 PM

Yes, try that first.

Hunter

97_ZJ_Limited · 02-21-2006, 10:49 PM

thought id dig this one up instead of starting a new one. and so texaszj cant tell me to search

. well, if i just need to move my rear axle back, i can just move the arms out an equal amount on both sides, right? also, do i need to jack the jeep up or anything? embellish this please. and i only have rear adj. lca's.

**Woody** · 02-21-2006, 10:54 PM

You will need adjustable uppers, otherwise you'll mess up your pinion angle and go through U-joints like mad.

You have to raise the back of the vehicle to make the adjustment. I was going to ask how you were going to fit 33's with your setup. It takes extreme trimming to fit them without going higher normally.

97_ZJ_Limited · 02-21-2006, 10:58 PM

sorry, 2" spacers will be on tomorrow. shouldnt have a problem then huh?

**Texas ZJ1** · 02-22-2006, 03:25 AM

Even if you adjust the adjustables out, the fixed lengths could cause problems. Try what you've got and let us know.

Hunter

**Woody** · 02-22-2006, 06:05 AM

I tried to squeeze 33's on mine at 5.5" and without adjustable uppers or some rear fender trimming, no way.