Rear Sway Bar Angle and End Link Length
- Thread starter mphilleo
- Start date
I just checked, as precisely as a tape measure on bolt centers can be, and I have 20.5" on either side, eye to eye (give or take 1/32").
I can say with pretty good confidence that it still has the stock rzeppa joints. Is that going to be a big problem?
Okay, that's what I thought, your lower arms are set way too long. Factory is 19-13/16" and AT MOST, you should only set new rear adjustable lower control arms to 20" and that's with 3"-4" of lift. Shorten them up to no more than 20" and then reset your pinion angle accordingly and you should be in much better shape.
Also, you might want to find a new shop because the one you're working with... I don't know how much confidence I would have in them anymore or at least, based on what I've been seeing.
Well, if that's the case, you were given bad advice to buy new adjustable control arms. There is no problem with your pinion angle being set the way it is but it definitely wasn't necessary to do.
Thanks for all the input, I appreciate it. So, for starters, set the lowers to 20" eye to eye and leave the uppers? I believe both front adjustable control arms are set to stock length. I'm guessing it's best to leave those be since the Jeep has already been aligned?
It's kind of annoying to install adjustable parts and pay good money to shops that don't provide good service. At this point, I wonder if my axles are really aligned properly, but I don't have a way to mess that myself.
Yes, I would set your rear lowers to no longer than 20" eye to eye. The uppers will need to be adjusted as well but set so that your pinion is in line with your drive shaft or so that it's parallel to the output shaft, as it would have been from the factory. Being that the rzeppa joints aren't too particular, you don't have to be exact. This will help reduce the spring bow you are seeing and help eliminate any rubbing that you might have now caused by it.
It is very frustrating for sure. It IS the reason why I started to learn how to work on my own Jeep over 25 years ago.
Ok, that makes sense. Just to make sure I understand, would it be best to set the rear uppers back to stock length? Or is it possible I might end up somewhere in between?
I've definitely learned a lot from communities like this one and working on my JK. As far as I'm concerned, I'd prefer to do as much work on it as I'm capable of doing.
Hold on a sec, I just realized that you have a JKU and I need to point out that the factory rear lowers measure 19-5/8" from the factory. On a JKU, I typically set my rear lowers to about 19-3/4"-19-7/8" or at least, for a 3"-4" lift. I would not set the rear uppers back to stock unless you set your lowers back to stock as well. Doing just the uppers stock while the lowers are still longer will make them too short and your pinion will be dipping. Somewhere just a bit longer than stock (17-11/16") should be okay. That will get rid of the big spring bow for sure.
Awesome, thanks! FWIW, I'm pretty confident that the lift installed by the previous owner was a RC 3.25" based on the equipment and measurement (front jounce to spring perch). I suppose that would put me on the lower end of the measurements you provided.
So, just to get all the info, I measured my rear UCAs and they're at 20.5" like I mentioned earlier. The rear LCAs are 17.5". In the Metalcloak installation instructions, to restore 5° castor, they recommend 20 7/16" for the LCAs and 18 7/16" for the UCAs. The lowers aren't far off from their recommendation, but the uppers are about an inch shorter. Based on my understanding, that's the adjustment that corrects the pinion angle upwards.
I'm definitely considering your advice, but I'm also thinking about seeing how the spring bow looks with the Metalcloak spring alignment/retainer kit. I did grab a picture measuring current pinion angle and a wide shot of the driveline for reference:
I'm definitely considering your advice, but I'm also thinking about seeing how the spring bow looks with the Metalcloak spring alignment/retainer kit. I did grab a picture measuring current pinion angle and a wide shot of the driveline for reference:
So, after installing the coil spring correction/retainer brackets, and after the wheel spacers previously, I'm still getting that clunk under hard turn or backing down a slope/driveway, etc. regardless of speed. At this point, I'm left to make the uneducated assumption it's either a bad heim joint in the crummy Rough Country adjustable trackbar, a loose body mount, or something otherwise unidentified. I'm not confident it's drivetrain related, because it made this noise before and after the axle was re-geared (I haven't had the time to try that test another member suggested yet). It obviously seems to be operating fine in this state, and I wish I could figure it out, but I might have to chalk it up to a "lifted Jeep thing."
Correction, it might be whatever you have installed on your Jeep, what you chose to buy on top of it and how you chose to address this problem, kind of thing.
Yeah, I get it. It's nothing inherently wrong with the Jeep. I'm not blaming it at all. In my honest opinion, it was a mediocre lift install to start with. Then you're either stuck trying to play detective to the problems it created or scrapping it all and starting with a proper lift. Unfortunately, I chose to try improving on a poor lift kit instead of the latter option. So it goes.Correction, it might be whatever you have installed on your Jeep, what you chose to buy on top of it and how you chose to address this problem, kind of thing.
Honestly, I'm not saying that it "will" fix your problem but the one thing you haven't done is do what I suggested and that's to shorten your rear lower arms back to about stock or just a tiny bit more and then set your uppers accordingly. I get that Metalcloak is all the rage but what they are recommending is just stupid. It's always been stupid and I don't understand why they do it. The factory control arms are designed to have your axles travel in an arc and to sit dead center in your wheel well at a full bump. If you make them too long like social media trendy manufacturers state, this WILL cause things like your tires to sit too far back and rub at even a partial bump. Sure, correction wedges will help even out spring bow but they WON'T fix the other issues that come with it including coils rubbing up against the track bar.
Again, I'd be the first to say that my recommendations may not fix what you're hearing but I sure as hell wouldn't be okay with just writing things off as something I have to live with. But then, that's just me.
duktrx
Active Member
Have you checked that everything is appropriately torqued down?
Are you sure it is in the rear end? Sounds have a way of traveling through the vehicle. I had what I swore was a noise coming from the back end; I could even feel it in the gearshift. I took it to the tranny shop, I trust; the owner test-drove it and said, bad u-joint. Ended up being the front passenger side.
This ^^^ Things you think are up front end up being in the rear and vice versa. Sounds have a funny way of traveling.
GP NOIR
Hooked
Are you certain you aren't getting the instructions for the front control arms mixed up with the rear? 5 degrees of castor is the setting for the front axle, not the rear axle.
Thanks for the insight; I might try adjusting those back this weekend. My uppers measure 17.5" right now, so just leave those, right? And the lowers measure 20.5" right now - I believe you suggested a different length in a previous post to adjust those to. I'm pretty sure of the answer, but I'll ask anyway: I should be able to make those adjustments to the rear lower control arms and that shouldn't overflow into needing adjustments on other components, right?Honestly, I'm not saying that it "will" fix your problem but the one thing you haven't done is do what I suggested and that's to shorten your rear lower arms back to about stock or just a tiny bit more and then set your uppers accordingly. I get that Metalcloak is all the rage but what they are recommending is just stupid. It's always been stupid and I don't understand why they do it. The factory control arms are designed to have your axles travel in an arc and to sit dead center in your wheel well at a full bump. If you make them too long like social media trendy manufacturers state, this WILL cause things like your tires to sit too far back and rub at even a partial bump. Sure, correction wedges will help even out spring bow but they WON'T fix the other issues that come with it including coils rubbing up against the track bar.
Again, I'd be the first to say that my recommendations may not fix what you're hearing but I sure as hell wouldn't be okay with just writing things off as something I have to live with. But then, that's just me.
Honestly, I can't say for sure 100%. You are right, though, it's possible it's something more midboard. I still need to check some of the skid plates and things of that nature. The front outer u-joints have been changed, but I suppose it's possible the rzeppa driveshaft might be popping under load?
I'm basing my measurements off of Metalcloak's instructions which have this chart (same one for the upper and lower RCAs):
Beyond that, I can't say just looking at it whether it's way off base or not.
I've been pretty well tied up with busy season at work, but I'm going to take @wayoflife 's suggestion regarding rear control arm lengths. Thanks for weighing in, everyone.