MaddXJ85

ok not sure if this goes here or in the fab section. sorry if its in the wrong spot. I'm wanting to make a set of LCAs. I have 4.5in rubicon springs. Does anyone know how much longer the LCAs have to be than stock? Any help would be great, thanks in advance.

muddeprived

Are you making them adjustable?

If not, aim for 16.25" to 16.5".

You should actually set up the pinion angle with a couple jacks and then measure the length from bolt hole to bolt hole. Or the easiest way is to make them adjustable from 15.75" with 2" of adjustability. There are a couple charts on the web that give you a ballpark measurements BUT these didn't work for me. I found that they focus more on caster and neglect pinion angle.

What I do is put a jack under the pinion and a jack under the trackbar axle mount. I raise and lower each jack until I get my pinion about 1 degree down from the driveshaft and then I lengthen my adjustable lower arms to fit. That's pretty much how you would measure for the length you need. Even if you are not dead-on accurate with the length you can still get more or less length from the caster shoes in the lower control arm frame pockets.

MaddXJ85

thanks for the advice that makes sense... i put a pair of skyjacker LCAs form a grand cherokee on and they are 17". the problem im having is that it still seems like my axle isnt pushed far enough forward... or is that not my concern..? see im havin problems here cause im piecing my lift together one piece at a time and im not mathmatically inclined enough to figure some of this out... could i send you some pics and show you what the problem is?

muddeprived

Are they 17" from center of hole to center of hole? That's pretty long for a short arm. You need to be able to push both upper and lower arms forward to get the axle to move enough to be noticeable. Send pictures if you would like. I'll help ya out.

Measure the wheelbase and see if it's 100.4".

MaddXJ85

OK sorry I couldn't get pics up yesterday. My normally slow life got suddenly busy lol. Heres a couple side views of the drivers side spring th bow in th spring is what I'm trying to correct. The way I see it if I were to extend the uppers the same amount as the lowers this should fix my prob but I just need to be sure before I go to the work of doin that lol.

MaddXJ85

Oh and yes the new lowers are 17" from hole to hole

MVDCXJ

It looks like, to me anyway, that the lowers you have on there are too long and are causing the front axle to shift clockwise (if you are looking at it from the vantage point of the pictures you took) thereby causing your issue. Thats just what it looks like to me but I'm a newb so. . .

muddeprived

Yeah lowers are too long or the uppers are too short. Your sway bar links are also too short.

Here are some options...

For adjustable uppers:
http://www.ironman4x4fab.com/Jeep_XJ...s/XJ_FUCA.html

sway bar links
http://zoneoffroad.com/product-acc?ki=67&gr=

(last item at the bottom)

Those will fit perfectly. (i run em )

MaddXJ85

OK thats what I thought.. Thanks for confirming.. I'm in the process of making sway bar disconnects it was just the damn curve in the springs that was throwing me off a little.. So considering that my lowers are an inch longer than stock I should make the uppers an inch longer also right? And do you have any advice on a tracbar fix? I know I should get an adjustable eventually but thats not currently in my price range.. Is there any other options for that just to get me by till I can afford to pick one up? I really appreciate your help!!!

Mike1998XJ

I believe on the 3.5" RE lift I installed the lowers were only 3/8" longer than the stock ones. If your lift is 4.5" that seems like +1" on the lowers is too much per the dimensions RE uses.
Just thinking out loud...
Mike

MaddXJ85

yeah I figured out that they're a little longer than what would normally be used but I was kind of wanting to push my front a little further forward anyway so I thonk it'll work out ok. I really appreciate everyones oppinions and ideas though its nice to have an outside look at things. And I REALLY appreciate how nice everyone is being about it. In my last thread I got a few a-holes and it just ruined my day lol. Thanks again guys.

muddeprived

You should be ok with 1" longer arms BUT make sure there's clearance between the tie rod and sway bar link (passenger side). What happens is when you push the axle too far forward, that tie rod that connects the tie rod and draglink (right in front of the passenger sway bar link) is too close to the axle and rubs on the sway bar when you turn to the right. I ran drop brackets with 4" lift and it pushed my axle too far forward and it binded right there and ruined my tie rods.

You can re-drill the trackbar axle bolt hole over 3/4" for a temporary solution until you can afford an adjustable trackbar.

For the arm length, stock measurements are 15" uppers, 15.75" lowers. Try not to guess on how long they need to be. Measure to find the ideal length if you plan to keep those longer lower links. See my post #2. Tilt the axle till the pinion is roughly 1 degree or parallel with the driveshaft and then measure the upper bolt hole to bolt hole. If you can, before you measure, make sure the lower control arm frame bolts are pushed back all the way in the adjustable slots. This will shorten em a little and get you better angles.


Lower Upper

********Decimal**Fraction**Decimal**Fraction

Stock........15.75.......15 ¾........15.00.......15
2”.............15.92.......16............14.88 .... ...15
3”.............16.09.......16............14.92 .... ...15
4”.............16.33.......16 3/8......15.03.......15
4.5”..........16.47.......16 ½........15.11.......15
5”.............16.62.......16 5/8......15.21.......15 ¼
6”.............16.97.......17............15.44 ... ...15 ½
7”.............17.36.......17 3/8......15.74.......15 ¾
8”.............17.81.......17 ¾........16.09.......16

(this chart is a rough estimate to get it set and then you have to dial in the pinion angle)

MaddXJ85

OK sounds good. So when i jack up the pinion to get my angle I should leave the Jeep sitting on the ground correct? Or would I have to put it on jackstands? Just wanna double check everythng I dont wanna do this twice lol. Thnks again for your help btw.

muddeprived

On the ground at ride height. When you disconnect both upper arms, make sure you have a jack on the pinion and a jack on the trackbar axle mount so the axle can't twist.

nw-xj-scott

brake lines are not long enough for any kind of flex either..