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My lift is off kilter


CO MJ
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10 hours ago, Eagle said:

 

Well, that's your problem. In order for the shackle angle to be correct when you put in lift springs, the main leaf HAS TO BE longer than the OEM main leaf. What you need is the eye-to-eye distance, at curb weight, to be the same. That means the main leaf length measured along the arch has to be longer.

 

Just measured the length of the main spring. Old is 56, new is 58. Don't think that's enough for 4.5" of lift while maintaining a safe shackle angle. I've sent this info along to rustys.

 

@75sv1 not a bad idea, but this kit is sold on the premise that I should be fine with stock shackles.

@ghetdjc320 Agreed. Even if they settled the shackle is still going to be at an awful angle, and they'll probably smash into my frame ever time I hit a bump. This was a full kit for MJ so plan B better be them sending me the correct springs :)

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Still waiting on his response, but I'll share some pics that he posted to get you an idea of finished product. Still not completely sold on the shackle angle. There will be settling, but as @ghetdjc320 said it won't be a lot.

 

I'm going to ask just because it hasn't been yet. Are you installing with the DS and Shocks removed?

 

Installed Wrong:

image.png.eb48b114f4b5f9434e49bb0de1ad5dc9.png

 

image.png.71776bf8409101ce5d2f01d6dc86234a.png

 

Installed Right:

image.png.dd3d36b21414626dbdeb985bad214cda.png

 

image.png.fb6487ed48eba889c6f06a6f9fb4da28.png

 

 

Someone did this to get theirs sitting right. Not sure how I feel yet lol:

image.png.8502264c6a0dffd36d0277bdd84e6a35.png

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@howeitsdone you're the man, thanks for those, giving me hope! I think I will pull the shackle bolt and see if I can persuade things into position. I'm not sure what DS is, but I did install with the shocks removed as per the instructions (which to be honest, absolutely terrible). Frame bolt, shackle bolt, axle bolts, shocks, in that order.

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20 hours ago, Big_Mark said:

Andy if he measures the way you describe his new springs are going to measure longer because of the lift (top spring measured flat will be 3-5" longer than stock) eye to eye is the way to measure here as that is the cause of the shackle position.
 

 

No. The inverted shackle position is caused by the combination of main leaf length and spring arch. If the main leaf is too short or there's too much arch, any time the vehicle is up on a chassis lift the rear spring shackles will flip to the inverted position when the vehicle is lowered back onto the ground.

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5 hours ago, howeitsdone said:

He just got back and said he did something like the last pic I posted. He put something between the frame and spring to keep the shackle from inverting while he jacked up the spring to flatten.

 

Ended up doing the same this afternoon. Looks better, still not perfect, and the driveshaft angle hasn't really proved. If springs settle another inch I think I'll be okay though.

A9F9F907-4F82-4525-AA78-CD999FE7AE47.jpeg

3B50C039-DBED-4067-9768-F11ABA801F47.jpeg

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Much better. A bit inverted still for ideal operation. A nice pothole could potentially invert that. The other side looks better. Your springs should be longer in the rear.

 

Settling won't fix that pinion angle. For the most part, your perch position dictates that. Like I said earlier, if you swapped the axle to SUA without positioning the leaf springs first then that will lead to your problem.

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36 minutes ago, howeitsdone said:

Much better. A bit inverted still for ideal operation. A nice pothole could potentially invert that. The other side looks better. Your springs should be longer in the rear.

 

Settling won't fix that pinion angle. For the most part, your perch position dictates that. Like I said earlier, if you swapped the axle to SUA without positioning the leaf springs first then that will lead to your problem.

 

Not sure what you mean. Stock config is SUA right? How can you position the axle if it has to sit on the pin fixed to the leaf pack?

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43 minutes ago, howeitsdone said:

I misread your initial post. You said "axle over spring" and my brain said "spring over axle". You either get shims or re-weld.

 

So I have shims installed that came with the kit, it might behoove me to just remove them. I think they are 6 degrees. PO must have put the plates on the axle with some angle, I bet removing the shims will put me spot on

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On 9/22/2022 at 9:34 AM, 89eliminator said:

i think you'll still have big issues with the shackle swinging forward.  something is really not right.  i ran the 4.5" rustys springs many moons ago and they werent even close to that bad in relation to the shackle angle.  

 

Any chance you have a pic?

 

On 9/23/2022 at 6:18 AM, 75sv1 said:

I'd put weight in the bed to compress the springs a bit. That should put the shackle angle closer to what it should be. Also, hopefully prevent then from flipping to the front. 

 

On 9/23/2022 at 1:08 PM, Airborne Janitor said:

I think at this point you should back it up to a tree, put a strap around the tree and your rear axle, drive forward a tiny bit to "pull" the axle rearward to correct your shackle angle. Then throw 1000lbs of stuff in the bed and leave it for a week.

 

Not a bad idea, wonder how much of this is just not trying hard enough to get them in the correct location during install. Rustys insists these are the correct springs and the numbers do match the screenshot of the video earlier in the thread so maybe if I can force them to the right spot maybe they'll eventually relax and hold.

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I have the Rusty's 4.5" on mine. I used the shims they sent with with the kit. My shackle angle wasn't that bad but it wasn't great either. 

IMG_20220926_192608550.jpg.273919b1d8920f62b52c28f7ae5a9549.jpg

I'm guessing this is the tag # your talking about. Mine have sagged a little bit but not allot.

 

 

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On 9/22/2022 at 7:34 AM, 89eliminator said:

i think you'll still have big issues with the shackle swinging forward.  something is really not right.  i ran the 4.5" rustys springs many moons ago and they werent even close to that bad in relation to the shackle angle.  


I'm a little late to this thread, but 100% agree with 89elim and Eagle. 

shackle is still inverted, no good. 
I would be contacting rusty's again and be adamant you want to swap the leaf springs out.

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Quote

 the spring will relax as soon as you use it and it is designed to have the shackle pulled forward , you can leave like you have and the leaf will relax and be too long , then you can put back like it belongs and go that way , we have designed this spring and it works prefect once you install and use it, the spring will relax and go right into shape and the shackle will have a 10 degree angle towards the TC , just as it should. I can promise you got the correct springs and they are installing correctly and will settle right into place. 

 

This is the last response I received from Rustys. I'm not an automotive engineer but from everything I've read there's a good reason for the shackle to be perpendicular to the eye to eye line of the springs, which makes their response very suspect. Not sure what TC stands for, but there's no way these springs are ever going to relax so much that I get into correct alignment. There must be 30-40 degrees between where they are and the correct angle.

That being said, I just want to make absolutely sure it's not something I've done incorrectly before requesting new parts to do the job again, but I've followed the install instructions to a T, so I very much believe that is not the case.


Here's another question. Should I have sprung for the adjustable control arms? After a little bit of driving, I feel like I am being pulled all over the place, steering feels off, etc. I  adjusted the track bar and have the body perfectly centered, but I have not checked camber, caster or toe. With stock uppers and the fixed lower control arms, am I able to do anything about the caster angle? Presumably I've lowered the angle by lifting right?

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TC = Transfer Case

 

Here is a great video explaining the differences between shackle angles and why you wouldn't really want to run like they're suggesting. Not sure why Rusty's would design it for a more stiff setup. I'm beginning to think this kit needs to have the shackle mount relocated. Either way, getting new components won't change anything if that's how it's designed. I think running with some weight in the rear for now to break them in is best bet unless you decide to return. I'm sure there is a nice restocking fee though.

 

 

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