Hey everyone what's up! Intro post to share. Just bought a new to me 2012 Jeep Jk. Previously had a TJ for the past 5 years and have our first kid on the way so needed something with more doors. I bought the jeep with all the modifications on it.

Jeep has a 3 inch lift. Rock Krawler lower arms maybe synergy uppers
Jeep has anti rocks way bar.
Flipped steering with Reid knuckles
dana 30-4.88 gears.
Adams drive shafts
Ten Factory axle shafts.
A bunch of other stuff...

Needing some help and some of the people over on Facebook just arn't helpful. Bought the jeep maybe 3 months ago and it has been issue after issue. I bought it from a small auto shop who said he bought it with a bad transmission, rebuilt the transmission and checked everything over. Stupid me believed everything and I bought it. Front end seemed loose so I took it to a shop to get checked out and confirmed that some of the front end components were shot and needed replacing. Also noticed at the same time that one of the rear springs was cracked... Ordered new springs and 1 ton steering and thought I should be good to go. Took it to get an alignment and shop said Axle is twisted based off my Caster. one side was 3.01 degrees other side was 1.65 degrees.


Got a couple Questions.....Not sure what route to go. Started looking for options of what I could do besides getting a new axle and having to swap everything over and regear.

1. Started taking stuff off the front end and notice both lower control arms have a TON of play in them... Any way that my Adjustable control arms are effecting the Caster differences.

2. Does it really matter if Caster is so far off with the left and right... based off of what I know so far I think that Caster won't effect tire ware.. what does cross caster effect.

3.Come across Caster ball joints... Was wondering if anyone has experience with putting on an offset ball joint to get my Caster closer.

Would love to keep the same Axle... Get it good to go, add a truss and gusset and run it.

 

before jumping to any drastic conclusions, you might go measure your front control arms bolt to bolt and make sure they are the same length on both passenger and driver's sides.

 

Bottom were both the same length but both complete shot. So much play in them.

 

And I am totally baffled on how the front axle could twist given stock engine and geared to suit tires. Rears like mine can twist the tube in the pumpkin with my V8 conversion but I am with Resharp on this from what you are saying about slop. Must be a bear to keep straight on the highway with all that wear and tear on suspension components. A little bit of caster difference side to side is ok but I would rebush or replace worn out items first then do the checks on the alignment machine. Make sure you are running about -5 degrees of caster as well when you are done which should be easy given adjustble arms top and bottom.

 

Dug a little deeper into the jeep. Turns out it had an accident at some point front right corner looks like that might have twisted the axle hard to tell though. So far it doesn't drive horrible. Im going to get the front control arms figured out and get an alignment again. How much difference in caster from side to side is ok? I know factory tolerance is like 0.5 maybe? But realistically how much is ok/ How much can I tweak with an offset ball joint if needed. Would rather not pay for a different Axle and the regear and everything.

 

I’m just thinking out loud here (ie, possible random rambling). I have a hard time seeing how a C could twist around the axle tube due to an accident, and if anything I think if it was possible the more likely result would be it would twist backwards and increase the caster (running into something or being hit from the side….you’re not really being hit from behind the front wheel with forward momentum). I also find it hard to believe the front axle tube twisted altogether. You can look for signs here at the diff –




I find it much more likely that control arms would bend or even that the axle tube would bend with enough force. As Sixty4x4 points out, it takes a s-load of rotational force (usually from high torque and HP) to twist those tubes pressed into the pumpkin or even a C onto the tube…..but I guess anything is possible and I certainly have no expertise in this area. I suspect the mismatched adjustable control arms might have been an attempt by the previous owner to correct some of this.

Regardless, you’re in the situation you are in. The first thing I would do is get all those control arm joints in order. Remove, inspect, rebuild or replace if necessary. Is this jeep just a pavement rig, maybe light wheelin type things? If so, I guess offset BJs are a simple solution to dial in as much as you can. That said, the 3° on your driver’s side is really low. You should have that caster up over 4° at a minimum. If you have adjustable arms that shouldn’t be a big deal. Get that driver’s side caster inline and then use offset BJs to get the passenger side as close as possible. Like Sixty….I’m surprised that jeep isn’t wandering all over the road with such large cross caster.

Another thought for those that are a bit more adventurous is keep your eyes out for a JK D30 bare housing for cheap. Pre-covid days you’d likely be looking at ~$300 for something like that. Who knows now. Anyhow, it would be pretty easy to pull the carrier and pinion out of the current axle and toss them in a different housing. Odds are super high that the current pinion shimming would be perfectly fine, and if anything you might have to reshim the carrier, but that is really straightforward stuff requiring only a dial indicator to check backlash, shims if necessary, gear paint to check pattern, bearing race driver (can borrow from stores) to get the pinion bearing race in/out of the housings, new pinion seal, new axle seals, and some common sense when it comes to the pinion nut. My point here just being you’re not looking at a full regear price to move to another axle since you could use your internals. That is probably not realistic for a lot of folks, but it is an option.

If you do heavy wheelin then it would likely be better to just replace the axle and/or housing. If you were doing heavy wheelin a D30 really isn’t enough anyhow.

 

I’m curious to see the alignment printout. With all the bad parts you’ve mentioned, I question whether the shop you used was any good. A good alignment shop will take 20 minutes and inspect the ball joints and rod ends to make sure the axle is solid in the first place.

I wonder what the thrust angle is between the front and rear axle. Did the alignment shop square the axles to the vehicle? If not, and if your front axle isn’t straight to the rear axle and the frame, then you could potentially see a difference in the caster since one side would be further forward than the other resulting in that difference.

I do agree with @resharp001 that the axle tubes aren’t likely to twist like that.

Start by getting your control arms and ball joints in order, then find a better alignment shop.

 

 

Maybe I’m not up to speed with how these machines work but I don’t understand how he can tell anything about the caster when the camber is out. Someone correct me if I’m wrong but isn’t the caster measured by a difference in the camber from -20* to 20*? So if the camber is out, the caster wouldn’t be measured right.

 

I didn't know that you could do that. I thought the caster was the forward or backward angle (looking at the side) and the camber is the tilt left or right looking from the front.