justinstoffregen

Thx, I will snap some pictures soon. In regard the the BJs, its been about 2years and I had both upper and lower replaced. I will research the brand in my extensive library of maintenance paperwork and post.

resharp001

Just to expand further on that camber and relation to ball joints -



Ignore the "positive camber" label as i forgot to erase that, and excuse my rough drawing of BJ's (red) and a knucle (blue) above.

The ball joints in the axle C are holding the knuckle, to which the unit bearing, brake rotor, and wheel are attached. The lower BJ is taking all of the load (except for Rare Parts), and the upper BJ is just helping hold position. When the BJ goes bad, it can no longer hold the C at the proper angle, and what you end up with is negative camber. You could also end up with negative caber if you bent the C on the axle with would result again in the knuckle sitting at an improper angle.

You may already be 100% clear on this stuff, but maybe someone will run across this in the future and benefit from it. Depending on what ball joints you previously replaced with this may or may not be relevant. Here is what the factory BJs have inside em -



Upper BJ on left, lower BJ on right. If one of those plastic tabs on the lower BJ break or crack, it's shot. When larger tires are added to the JK, you're putting a lot of additional stress on these things, and even one big jolt could doom em. If you replaced with something like an Alloy, Synergy, or other BJ 2 years ago, you're likely fine. If you replaced with factory, not certain you can eliminate them as an issue just cuz it was 2 years ago. That is why I asked about brand.

justinstoffregen

Great info here. Thank you. The BJ's I got are Moog. They are fully serviceable.

justinstoffregen

I talked to mechanic and a couple of other guys and they all seem to think that the caster is not the culprit or too far out of line for a lifted Jeep. I'm not saying it isn't hurting but...

justinstoffregen

Tires rotated, pads checked, bjs checked, last alignment diagnosed. The only discovery was a worn bushing on drivers side rear swaybar end link. Again, probably not the culprit but will report after I add two new ones.

jdinny

I would put a set of Geometry Correction brackets on your Jeep.
Don't believe that's causing the pull, but it will fix the caster issue and make your JK much more fun to drive.

justinstoffregen

Thanks! I will look into those.

resharp001

All I'll say is this, you can agree or not agree. 2.5* caster is as far out-of-line as we see on lifted JK's for the most part. I've driven with sub 3* caster, and I've driven with proper caster, and will only say it's a very big difference. I try not to link this video as I am against one specific comment I find offensive as the father of a child that has special needs, but, the bicycle example towards the end is by far the best real world example of caster.


The whole video has good information, but if you want to skip to the example, scoot forward to 3:10.

Now, my impression is you've had this jeep set up like this for a while, without any significant changes. Your caster didn't recently drop sharply. It sure isn't helping your issue is what I'm saying, but I have to think that it's at least some contributing factor. Even if it wasn't, sub 3* caster shouldn't be acceptable to any JK owner, and it's something you should seriously consider fixing. People chalk up a crappy driving jeep to "oh, it's just a lifted jeep and that is how it is", but that's not the case. I'm on 3.5" lift with 37s and can drive 80mph down the highway while taking my hands off the wheel. I wish that more people would have chimed in on this thread so it didn't seem like I'm the only one saying this, but I'd bet you would find that most people are going to side with me that sub 3* caster isn't correct.

nthinuf

Yep. While possibly not the main issue, low caster certainly isn't helping the situation. As noted, the numbers don't have to change much to make a noticeable difference in the steering.

I only skimmed the thread so may have missed it, but which tires are you running? (A few have been reported to cause a pull to one side.) How old are they, and how often are they rotated?


Just looked at your profile. Mickey Thompson MTZ's. Haven't seen any posts relating these as the cause of a pull.

Sltimmins

I'm with resharp, I used to have a RC 2.5" lift with no control arm correction and about 2.5* caster. It was awful but like a lot of people I chalked it up to "it's a lifted Jeep." After a few more months I finally decided to get a set of drop brackets, let me just say, it made a HUGE difference, in ride quality and handling. Last fall my RC lift had sagged so much and the shocks were shot I decided to go with a full MC system with all 8 arms. Now at 2.5" of lift all 8 arms is probably more than I needed but I wanted to be able to get my suspension dialed in perfectly as I wanted to run 37s on 2.5" lift. It may be a combination of now having a high quality suspension and having my caster dialed in at exactly 4.5* (which is a little higher than factory). But let me tell you, my Jeep is nicer to drive and handles better than my ex's Audi. (ok that might be a bit of an exaggeration but the Jeep is better than it ever was stock) But resharp is 110% right, sub 3* caster should not be acceptable to any Jeep owner and I would seriously consider fixing it although it probably is not the culprit of your pull.