JK: Installation and alignment of most lift kits with new arms and trackbars - JKowners.com : Jeep Wrangler JK Forum
 
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post #1 of 9 Old 01-06-2015, 11:53 AM Thread Starter
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JK: Installation and alignment of most lift kits with new arms and trackbars

I was reading about some issues that someone was having regarding the proper installation of a lift kit (on a JK) he was installing himself. It lead me to publish this write-up of the procedure I have used (past and present) to install suspension components and perform a wheel alignment on my JK. Here you go...

1) Follow the instructions provided by the lift manufacturer to get the lift components installed on the JK; while keeping in mind that once it's all installed, you're still only at a starting point regarding proper articulation clearances and suspension alignment of the components. The control arms and track-bars jamb nuts and end bolt/nut assemblies should be "lightly" tightened at this point (both ends); while the new suspension component attachment brackets should be torqued down to the recommended specs.

2) Start at the rear by adjusting and squaring your control arms: Hopefully, when you installed the rear control arm frame brackets (if you replaced the OEM brackets); and if you noticed any play in them; then you biased their install toward the center (forward) of the JK. The front replaced control arm brackets should be biased (if necessary) toward the center (rearward) of the JK. Generally, if your kit replaced the OEM brackets; then they probably went on with very little play; so it is what it is.
Carrying-on... With the JK sitting on level ground, on it's new suspension, new tires (all tires at the same pressure, use 35 psi for now, you can adjust when your done here) and the rear pinion angle set as close as you can to a straight line with relation to the drive shaft... length-measure and cross-measure the upper control arms, from axle housing bracket end to frame bracket end (center to center). Do the same for the lower control arms. Take your time, be as precise as you can, and write everything down. The upper arms should be the same length as each other, and their cross measurement should be the same (right lower to left upper and left lower to right upper).The lower arms should be the same length as each other, and their cross measurement should be the same. If they aren't; then adjust accordingly. Once the length of the arms are the same; then the cross measurement should be the same. Lightly tighten the arm length jamb-nuts at this time.

3) Center your rear axle housing: Measure the centering of the rear axle in relation to the rear frame rails. Measure (with a ruler held evenly across the bottom of each frame rail, at a point perpendicular to, and directly above the axle housing center-line) from the right and left outer frame rails, to the inner sidewalls of the rear tires. The measurements (right and left) should be the same. If they are the same... good, your rear axle is centered, and you can move on to Step (4).

If they are different; then calculate the difference in the measurements divided by two. This calculated amount is the distance that the axle needs to move toward the shorter measured side. To adjust the axle center, you need to adjust the length of the rear track-bar; which is on an angle. Due to that angle, the measured amount of movement necessary at the axle will be slightly more or less on the track-bar; than the amount you calculated; depending on whether you are lengthening or shortening the track-bar.
So, if you need to lengthen the track-bar; then set the length of the track-bar (center to center) to an amount slightly longer (1/16th" to 1/8th") than the original length (before you removed it) plus the calculated amount. Conversely, if you need to shorten the track-bar; then set the length of the track-bar (center to center) to an amount equal to the original length less the calculated amount. Install the track-bar and set the JK back on the ground and remeasure for axle center using the method described above. Readjust as necessary. Use a small come-along or ratchet-strap to move the frame and body right or left in relation to the axle housing. This will aid in removing the binding at the brackets and ease the centering of the track-bar end bolts into their respective brackets. Your rear axle is now centered relative to the frame/body.

4) Verify the length and squareness of the front control arm mounts to the rear control arm mounts: Length-measure and cross-measure from the rear control arm frame mounts to the front control arm frame mounts, center to center (uppers to uppers and lowers to lowers). The length measure should be the same; and, if so, the cross measure will be the same. If that's the case; then your front control arm mounting points on the frame will be square to the rear control arm mounting points; and you're ready to proceed to centering and aligning your front axle housing and steering wheel Step (5).

5) Setting your front axle housing square to the rear axle housing: We will assume that you have the front pinion angle set close to the lift manufacturer's recommended angle; and that you did so by following their instructions, and using their recommended lengths.
That being said, verify that the upper arm lengths are the same; and the lower arm lengths are the same. Cross-measure the uppers and the lowers. The cross-measurements should be the same for the uppers; and, as well for the lowers. If that is the case; then proceed to Step (6).

Here's where it gets a little tricky...

If the length-measure on the frame, from
Step (4) is not the same (right to left); then you'll have to correct for that when setting the length of the front control arms, in order to make sure the front axle housing is square to the rear axle housing. Determine the difference in length measurements made in Step (4) above; and divide by two. We'll call this the calculated amount.
Using the length measurement recommended by the lift manufacturer for the upper front control arms; subtract the "calculated amount" and set the length of one upper control arm to that new measurement. Install that upper arm to the side of the JK that measured longer in Step (4) above.
Conversely, set the length of the other upper control arm to a measurement that is one "calculated amount" longer than the manufacturer's recommended length. Install that upper arm to the side of the JK that measured shorter in Step (4) above.
Perform the same procedure for the right and left lower control arms. Add one "calculated amount" to the length of the LCA that you install to the shorter side measured in Step (4); and subtract one "calculated amount" from the length of the LCA that you install to the longer side measured in Step (4).
Do not cross-measure the arms; as they are different lengths; and, therefore will not cross-measure the same. Length-measuring from the rear-arm-brackets at the frame, to the front axle-arm-brackets should measure the same (with the adjusted arms installed). Have a friend help you with the longer length and cross measurements.
Cross-measurements from the rear-arm-brackets at the frame, to the opposite side front lower ball joints should be the same, or close; depending on how "off-center" the front axle housing is [see Step (7)]. Double-check the front pinion angle and adjust it, if necessary, by lengthening or shortening the upper control arms in equal amounts.

To be continued in the next thread...

6" FTLA w/HD TB & SS,
JKS spg rets., rr spg mnts.
37" BFG KM2, 17x9 MT clssc II, Blstn 5100,
Finishline West RB, LoD FB, SB XRC10
PP mod'fd boat sldrs, ARB rr DC's, TERA 44 frt xl hsg,
Sup'r CrMo xls, 5.13 R&P, Reel 1310 DS,
Kilby Evap, Bnchmrk KISS, B&M Trans culr,
sPOD; Aeroforce, FlashPac, Airaid CAI, Magnaflow relo,
Cobra 75, 4' Firestik, Woods Hood & TG holds
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post #2 of 9 Old 01-06-2015, 11:57 AM Thread Starter
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JK installation and alignment of most lift kits with new arms & track-bars continued

Continuing on...

6) Set your toe-in: The JK is on all fours, on level ground. Center the front tires by eye; so that they look like they're parallel to the rear tires; when viewed from the rear of the JK. On one front wheel, measure the height of the hub center from the ground; write down the measurement. Using a piece of chalk, draw a cross on the front of each front tire at the center of the tire tread (or as close as you can), at a perpendicular/vertical distance from the ground equal to the height of the hub center. Have a friend help you measure the distance from the center of one cross to the center of the other. Write it down. Jack one tire off the ground and rotate it 180 degrees; such that the cross will be at the hub height upon lowering the tire to the ground. Do the same for the other front tire. Measure the distance from the center of one cross to the center of the other (now at the rear of the front tires). Write it down. The distance between crosses measured at the front should be 1/8" to 1/4" shorter than the distance between crosses measured at the rear. Adjust your tie rod until you get the desired measurement differential.

7) Center your front axle housing: Length-measure from the front lower control arm frame mount to the center of the corresponding lower ball joint (right and left). Cross-measure from the lower ball joints to the opposite front lower control arm frame mount (right and left). Write the measurements down. The length-measures should be the same, or very close; but the cross-measures will be noticeably unequal if the axle isn't centered. Center the axle housing to the frame/body in a similar fashion used for the rear by removing the adjusting-end of the track-bar (usually the axle housing end) and using a small come-along or ratchet-strap to pull the frame/body to the right or left of the axle housing; until the cross measurements are the same. Adjust the front track-bar length; so that it will install in the bracket. Lightly tighten the track-bar bolts/nuts.

8) Measure the wheelbase: First, center the front tires as best as you can by eye. Then, using jack-stands, or something similar, run a string-line from behind the center of each rear tire across the outer sidewalls at the height of the hub center; and forward, across the front tire sidewalls at the height of the hub center to a point in front of the center of each front tire; terminating at another jack-stand, or something similar; such that the string line is tight across all edges of the tires. Keeping the string lines taught, move the front jack-stands outward to the sides until the string line on each side, barely comes off the front tire's sidewall; either at the front or rear of the front tire. Turn your steering wheel right or left so that you even-up the distance that the string lines are from the sidewalls at the front of the tires (right and left). You are trying to get the string lines to be touching both edges of a rear tire; and the rear edge of the front tire, with the same gap (right to left) between the string and the front sidewall of the front tires. You can't achieve perfect parallel alignment because the front tires are "toed-in". Once you have the gaps the same, right to left; they should be about 1/16th to 1/8th inch wide.
Now, have a friend help you to verify that the wheelbase measurement is the same right to left. Measure from the rear wheel hub center to front wheel hub center, on the right; and compare to the same measurement on the left. If you were careful in all your measurements previously; then the wheelbase should be the same. If not; then you have to go back and do all the length and cross measurements again, to try to find your error. Once your wheelbase is the same; then go back and tighten all suspension bolts/nuts to the correct torque values. Tighten the control arm's and track-bar's jamb-nuts to the correct torque values. Lube all the suspension bearings and articulation pivots.

9) Center your steering wheel: Once the wheelbase is the same; then check to see if your steering wheel is centered, IE the "Jeep" logo is horizontally level. If it isn't; then block the front wheels so they can't turn right or left; and adjust your drag link, in or out, until your friend tells you the steering wheel is centered. Conversely, you can have your friend turn the steering wheel until it's centered, and hold it still in that position. This will miss-align the gaps of the strings to the tires. While your friend holds the wheel centered; you adjust the drag link until the string gaps even out, right to left; as they were when you set the strings up to measure the wheelbase. The adjustment of the drag link is easier if you take some weight of the tires by lifting the center of the front axle slightly. After adjusting, drop the axle back down and cycle the steering full-right to full-left and then back to center. Check the string gaps again for sameness. If they are the same; then tighten the drag link components you had to,loosen to adjust the steering. Lube the steering components.
Take your time and do it right; and you won't need to spend the bucks to pay for an alignment; because you've already done all the adjustments that are possible. If you do take it in to check the alignment and you don't get a good result; then ask the technician to explain where the problem is, and what he would do to correct it, before he actually performs any correction/s. Because... You can align the suspension without centering the axles; and your rig will drive/track perfectly straight. The wheels just won't be centered under the rig; which could cause clearance issues between the body/frame and the wheels/tires at extreme flexing. Additionally, if you squared and centered the axle housings; then you can use this procedure to do an alignment at any time in the future.

10) Some notes: I've never taken my JK in for a suspension alignment. I have no steering pull, and am experiencing no uneven tire wear. If you experience frame damage; then you'll have to re-check the length and cross measures. Otherwise you wont have to ever do that again; unless you change out your control arms.
I run two different sets of wheels and tires; and one set doesn't have the correct setback; so I use wheel spacers, front and rear. I need a larger spacer in the rear; so I can run rear tire chains, if necessary. I don't like to run a large wheel spacer on my front wheels; to minimize stress on the unit bearings; consequently, I run uneven spacers. Obviously, miss-matched tires front to rear will yield the same issue. However, even with uneven spacers; I can still use the string method to get my wheels aligned. It just takes a little more time to get the strings set up properly; so I can measure the "gaps" correctly.

I hope this article is helpful to any and all JK owners out there. If anyone would like some illustrations to accompany this post; then respond to me via private message (bear with me, as I'll have to draw them up). If anyone can find any errors in the logic or writing of this piece; then, please inform me of such, so that we all can be properly informed. Thanks for your interest.

6" FTLA w/HD TB & SS,
JKS spg rets., rr spg mnts.
37" BFG KM2, 17x9 MT clssc II, Blstn 5100,
Finishline West RB, LoD FB, SB XRC10
PP mod'fd boat sldrs, ARB rr DC's, TERA 44 frt xl hsg,
Sup'r CrMo xls, 5.13 R&P, Reel 1310 DS,
Kilby Evap, Bnchmrk KISS, B&M Trans culr,
sPOD; Aeroforce, FlashPac, Airaid CAI, Magnaflow relo,
Cobra 75, 4' Firestik, Woods Hood & TG holds
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post #3 of 9 Old 01-06-2015, 12:32 PM
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I can't use what the manufacture says for control arms #'s??

Lol... JK

Wonderfully done sir

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post #4 of 9 Old 01-06-2015, 12:35 PM Thread Starter
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So, what have/did you done/do?

6" FTLA w/HD TB & SS,
JKS spg rets., rr spg mnts.
37" BFG KM2, 17x9 MT clssc II, Blstn 5100,
Finishline West RB, LoD FB, SB XRC10
PP mod'fd boat sldrs, ARB rr DC's, TERA 44 frt xl hsg,
Sup'r CrMo xls, 5.13 R&P, Reel 1310 DS,
Kilby Evap, Bnchmrk KISS, B&M Trans culr,
sPOD; Aeroforce, FlashPac, Airaid CAI, Magnaflow relo,
Cobra 75, 4' Firestik, Woods Hood & TG holds
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post #5 of 9 Old 01-06-2015, 12:45 PM
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It was a joke. People always wondering why their alignment is jacked using the manufactures #'s. Either done them self or "professionally".
The track bar, control arm numbers given should only be used as a baseline or starting point.

2007 JKR | PSC Big bore box | Rock Krawler 3.5" x-factor arms l SteerSmarts YETI track bar, tie rod, no drill flipped drag link, Griffin | Synergy frame brace | 37x12.5x17 Nitto RG's | Dana front DS | Fox IFP shocks | Artec front armor kit/Currie JJ's | Teraflex rear axle bracket | EVO Rockstars | Ridged D's, A pillar mounts | VKS sliders l Trek Armor seat covers | Superchips/Sprint booster | Savvy half doors w/ Bestop uppers
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post #6 of 9 Old 01-06-2015, 04:25 PM Thread Starter
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I agree... If you start by using their measurement numbers, and you find you have clearance and alignment issues; then it's time to make your own determination on axle placement within the wheel openings. Ultimately, you want the axles to be in the OEM position, relative to the wheel openings; unless, your kit is designed to move the axles forward or rearward of the OEM position. One must have a "big picture view" of the ultimate goal, before starting the process. Thanks for your comments.
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post #7 of 9 Old 03-21-2015, 07:06 AM
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Nice write up. For whatever heaven knows reason, the kit mfrs leave the setup to chance, often fobbing it off on the alignment shops, many of which have no clue. One major vendor supplies front control arm length specs that are off by 1", which not only causes bad handling but component interference as well. The error is in both their short arm and long arm instructions. Despite having it pointed out to them, at last look they still haven't corrected it.


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post #8 of 9 Old 03-30-2015, 10:36 AM Thread Starter
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It's all too unfortunate... many manufacturers have that issue. I'm sure you've received "instruction sheets" that are not only displaying incorrect information; but are all too often illogical and/or unintelligible.
Many manufacturers do a great job creating detailed instructions that properly explain how to correctly install the item; but they can't teach a customer everything that one really needs to know about how that item should properly function, once installed. That takes a much more comprehensive understanding of the rest of the components of the various systems that are interacting in a dynamic scenario. In other words (and redundantly), just because it's a "bolt-on" item doesn't mean that your typical home/backyard mechanic has the background knowledge to properly perform the overall task. He may know how to properly operate the tools necessary to accomplish the installation; but he'll create more problems than solutions for his ultimate goal; when he's operating from a poor understanding of the basic intended engineering behind the components he is replacing.
Short version... just because you can bolt it on; doesn't mean you understand what it's supposed to do and/or how it's supposed to operate. "nuf said!
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post #9 of 9 Old 04-30-2015, 11:04 PM
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Great Info! Thanks for taking the time to write this.
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