RiverCityOffroad

I understand wanting to know what you're changing, and why, and all that, but seriously....take it to an alignment shop. Tell them you have adjustable front lower control arms and you want the caster set between +5 and 5.5* . That means lengthen the lowers if your initial reading is below that and shorten them if your initial reading is over that.

You can play with an angle finder in the garage and fight the arms and all that or you can take it to an alignment shop where they can support the frame and axle, drop the arms, make adjustments, and get you dialed in exactly where you want it to be without any hassle. It shouldn't cost any more either. Generally runs about $100 to dial one in even with adjustable arms. Again...I understand wanting to know how it works and you can definitely install them yourself. Set them to the MFG's starting length and then take it to the alignment shop. If you are dialed in where folks are recommending then leave it, you paid some money for peace of mind. If they need adjusting those guys can do it WAY easier than you can on the garage floor and its already on the rack. I see absolutely no reason to put them on, have it checked, go home, screw with it, and then go back and waste another hour or two at the alignment shop. The machine isn't going to lie.

The guys you mentioned should be able to help you (Sam's) and if you need a recommendation I have a ton of customers in your neck of the woods that I could ask who to take it to for you. Deviant Customs is about 1.5 hours from you and does a lot of suspension and fabrication. Look him up if you're looking for a shop in the future. His name is Jared.

Marcus

MikeOK

Thanks guys for being patient with me, sometimes the simplest things are the hardest for me to understand. I think I’ve hung around engineers too long.

I went out and checked mine, and my pinion angle is 2.6*, giving me 3.4* caster. About what resharp said it would be. I used the socket on the u-joint method and my iPhone so I could be a bit off. I couldn’t find anything else flat to measure it on. What the heck is a pinion anyway lol.

I asked this on another forum and got a good answer, but I would appreciate another opinion. I have read multiple places that I should use 23” on my new LCA’s as a starting point. Stock is 22 5/8”. That seems to be a large change, what do you think?

MikeOK

RiverCityOffroad- I called Sam’s and they will align for me for $89.95 and I have a coupon so I’ll definately take it there after I get them on. I just feel ashamed if I don’t do as much of my own work as I can unless it’s something like this that I don’t have the tools to complete properly.

nthinuf

Check around for shops that do lifetime alignments also. Firestone (mentioned earlier by resharp), Sears, and any other tire or alignment shops. Doesn't hurt to compare.

I checked with several firestones in both texas and colorado, none would honor the lifetime deal for my jk with adj arms. So if you talk to them, be sure to specify what you want before paying. My local sears in colorado had a good 4x4 alignment guy, but with the way they keep closing more and more stores, probably shouldn't be your first choice. Here in texas, I ended up getting a lifetime alignment through lambs tires, a local chain with a bunch of techs involved in local 4x4 groups. More expensive, but a lifetime deal might be something to look into if you are paying anyway.

kjeeper10

Haha !! Yea thats me.

MikeOK

I marked up resharp’s picture showing the way positive angle is measured. I couldn’t figure out which end was measured and which way was positive. For some reason I looked at the picture again and it just clicked. It just took my thick skull about 6 hours of reading and posting to figure this out. I want to lengthen my arms and lower the pinion just like you guys said.

Rednroll

My experience has been that most standard shops don't adjust LCA's to correct caster with a standard alignment. Some will do it, for an additional charge on top of the standard alignment charge....some won't. An alignment on a JK involves adjusting the toe and the drag link for steering wheel centering correction since that's all that can be adjusted in stock form and stock form adjustments are what standard alignment fees from the shops are based off of. Most adjustable front LCAs require a shop to take an alignment check, drop the arms, adjust the arms, re-install the arms, load the suspension, torque the arm bolts down, recheck the alignment, rinse, wipe, repeat. I don't know of any shops that includes that additional work to adjust the caster for no additional charge.

Really, in my opinion the best way to do this if you have a 2.5 to 3in lift is to adjust the arms length between 23in to 23 1/8". 23 inches is a common and proven number that has worked for many with a similar amount of lift on our JKs. Then after adjusting the arms to that length, take it into a shop and see what the caster comes out to, so you can establish a baseline specific to your rig as mentioned previously. 9 times out of 10, most will be done there. If not, then increase length to increase caster, or decrease the length to decrease the caster for fine tuning purposes if you're anal.

The recommendations to use an angle finder is just to provide yourself a sanity check that you're in the ballpark prior to taking it in for the alignment check. We all know it isn't 100% accurate. It's really an unnecessary additional check if you go by the 23in length proven rule of thumb.

Here's my alignment with the Mopar 2in lift....which is 3 inches of actual lift. LCA length set at 23 1/16"

BAM!!! 5.4 and 5.2, right about where you want to be with 3 inches of lift.


And here was my caster prior with the same lift and the arms adjust to 22 1/2" length. 2.9deg and 2.5 deg. Not bad, but was definitely room for improvement and thus the reason I went to 23 1/16" which was within the range recommended by many others.

kjeeper10

Agree

MikeOK

This brings up another question. I assume that the front bracket has elongated slots instead of a round hole that the bolt goes through, otherwise a cam bolt wouldn’t have anywhere to move the bolt to adjust the caster with a fixed length arm. Is that correct? I looked, and it appears that my front bolts are now approximately in the center of this slot. Do I set my new arms to 23” and use the same bolt location in the slot thus making my adjustable arms equivalent to the stock plus 3/8”? These slots appear to let you adjust 1/2” or more. And what makes these bolts stay in place in the slot under high loads? I would think that a big hit would make the front bolts slide even with 125 ft lbs of torque.

Rednroll- everything I’ve read says 4.2 is the stock caster. You’re saying I want over 5?

nthinuf

That's just a question, or are you now saying that you do have cam bolts? If so, you will probably want to order an eliminator kit prior to installing the adj arms.

Assuming cams have not been installed : when the bolts are removed, there should be square holes in the brackets. As part of cam bolt installation, those holes get enlarged, notched out along a perforated section. At that point, the cam bolts can be adjusted along that slot to raise/lower caster.

4.2* (+/- a bit) is the caster spec from the factory. After a lift, it is fairly common to run higher caster for better steering, anywhere from 4.5 up to 6* or so. But as was mentioned several times, higher caster = lower pinion. Lower pinion = more likelihood of driveline vibes, which gets worse the higher you go. (But if you think about it, since you have been running at a bit over 3* and say it's better than stock handling, I'd guess that raising it just to the stock 4.2 would be fine.)

Also, if you set it higher than stock and then go for an alignment, be sure and tell them so they don't drop it back to stock.