Leaf spring nightmare - JeepForum.com
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post #1 of 42 Old 06-11-2021, 11:13 PM Thread Starter
RARECJ8
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Leaf spring nightmare

All measurements are on center. Everything lines up. Yet we have a crazy off set. Center pins solid in right place. And yet. So tired of this CJ. All my CJ buddies that sold out and went to new JKs laugh at me. Still holding on to old iron but itís a never ending disappointment. Rear axle seems shifted to pass side but all #s says itís equal. Driver side shackle bolt now hitting fuel tank. DepressedÖ

Headed in for a 4 wheel alignment for measurements and go from there.

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post #2 of 42 Old 06-11-2021, 11:18 PM Thread Starter
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Front to rear center to center hub is 1Ē shorter on pass side than driver side. Meaning rear axle is not perpendicular to frame or Ö. Thats the best we can figure with a tape measure. So frustrated. 🔥

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post #3 of 42 Old 06-11-2021, 11:25 PM Thread Starter
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PS. All new components. Pax, shackles, everything. This after a 20 minute road test. Ugh.

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post #4 of 42 Old 06-11-2021, 11:26 PM
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Hang a bumb bob from the center of the rear hangers and center of the shackle mount, is the rear frame/hangers square? What is the measurement center of front spring hanger to center of rear hanger? Also is the center of the frame square?

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post #5 of 42 Old 06-11-2021, 11:50 PM Thread Starter
RARECJ8
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So far we know rear axle is not perpendicular to frame. Itís somehow twisted with pass side an inch fwd or driver side an inch back of center. Dog legging. Verified center pins in correct hole and u bolts tight. Something is clearly AFU. Thought maybe a sheared leaf pack center pin allowing it to walk, but no, itís all sold. In right hole. I need a couple shots of Jim and a night sleep. All my buddies on a run tomorrow and I get to sit home and speculate. Wifey not happy. Axle tubes in center etc tight and square. Maybe tweaked frame. Worst case use an axle plate off set to correct it but thatís not addressing the core issue. Or maybe it isÖlol.
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post #6 of 42 Old 06-12-2021, 12:12 AM
ctorj
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Did this just randomly start or was it after the spring over? Might want to check the leaf springs and measure from bushing center to center pin on both sides. One Leaf spring backwards will cause that.

Note - Center pins in leaf springs are not in the middle.
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post #7 of 42 Old 06-12-2021, 06:58 AM
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One thing I'd do is contact the company you bought those orbital shackle hangers from and maybe even send them some pictures of what you have going on. I'm not saying they are the problem but someone else may have had the same problem as you. It's too late to do this but if I were going to mount a different set of springs that required new hanger locations I'd establish the original location of the centerline of the axle in relation to the frame and make that my base line for locating the new one. Even if you want to move the centerline you always have that to measure to. You still have the other shackle hangers on the frame, correct? Those are a good reference too for checking what you now have.
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post #8 of 42 Old 06-12-2021, 11:40 AM Thread Starter
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the center pin on these pax is dead center between spring eyes. initially installed a set of used pax and new chevy OEM rear shackles. after ten miles driving you see what happened to the passenger rear eye. popped! Altho it looks like was already compromised the pass side spring wants to push outward. all 4 shackle hangers match the axle spring perch center holes. front hanger, axle perch holes and rear hanger all in a straight line, all exactly equal, yet we get this unwanted shifting, even before adding the orbital eye hanger. lifted the entire rear end so rear axle was hanging and the shackles reset to perfectly up/down. Drive around the block, clock and counter wise and after a couple miles we get what u see in the OP. going in for a 4 wheel alignment for some precise measurements to help diagnose the thrust angle issue. maybe... Now with factory brand new pax doing the same thing.
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post #9 of 42 Old 06-12-2021, 02:17 PM
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You say that all measurements indicate that everything is true but hub to hub measurements are not equal.

No way all mounting points are true and perpendicular to a straight frame with a different hub to hub distance.

You might want to recheck your rear main eye mounting points in relation to your frame AND your front main eye mounts.
The rear shackle spring eyes should trail a correctly mounted and true front main eye.
They should not be allowed to move left to right or stay on one side (passenger) or the other.

Are you using some sort of orbital socket on the front rear leaf main eyes AND the same type of socket on the rear shackle eye?

Although I understand the idea of an orbital shackle eye on the rear at the shackle hanger I totally disagree with the premise beyond that of a sales gimmick. Not to offend but it’s just not a good design despite the claims. Kind of like revolver shackles. I saw your other posts about converting to the Pax system and refrained from giving my opinion. Sorry.

Leaf springs are not designed to rack back and forth at the shackle hangers. I don’t get why company’s sell a product brought over from a link type suspension system as a viable option for a leaf spring system…the two do not function the same way, especially on a solid axle. Pax clearly shows the system they recommend with the orbital eye being used with a solid bushing on the leaf spring eye at the shackle. Why do you have so much movement at the rear shackle bolt through the leaf spring?

I too looked into Chevy springs on my CJ8 as way of getting a bit more flex. After looking at the rear frame horns on my 8, how far out along the frame I would need to mount the hanger and the spring rate of a full size 63” Chevy spring (half ton trucks and larger) I decided the effort was way over kill without strengthening the rear frame horns. The difference in weight between a CJ7 and 8 is not as much as you think. The spring rate for a soft 63” Chevy is likely beyond what a heavy CJ8 would need or support. To me, the Chevy spring defeats the purpose of more flex when your rig (on the rear) is not able to weight the springs enough to feel the difference. An air ride or cushion system would further reduce the intended purpose of more flex. Just my opinion.

On another note, I’m building my Willys truck on a TJ frame with extended frame rails at the bed and I’m using Chevy springs. So, I get the direction your wanting go.
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post #10 of 42 Old 06-13-2021, 07:46 AM
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You may have covered this and I missed it. But could the axel perches be welded to wide? In you first pics it clearly looked like the springs are being forced outward at the rear shackle mount. Have you checked the distance between the two perches welded on the axel and the distant left to right of the spring eye frame mounts? I think they should be the same. Apologies again if already covered.
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post #11 of 42 Old 06-13-2021, 03:08 PM
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I had a somewhat similar problem with my Skyjacker springs . The front shackle would want to lean outward and had a hell of a time getting the shackles bolted together. Turns out the centerpin hole on one main leaf was offset toward the side about 3/32 of and inch (I forget the exact amount, this was over 10 years ago). Multiply that by half the length of the spring and it amounts to enough to cause problems. The other four leaves in the pack were ok. The pack did look a little funny when I got the springs. Fixed it by elongating the hole back toward center with a chainsaw file.
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post #12 of 42 Old 06-14-2021, 12:10 AM Thread Starter
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We measured every dimension every angle Kris Kross front to back side-by-side every number was perfectly matched suspension hanging no bind perfectly lined up then take it for a test ride it’s all twisted up like a pretzel. This system reflects countless hours of professional suspension engineers and all our befuddled with this circumstance. There is something fundamentally wrong that we cannot detect or observe. We have had this rig on the lift with tape measures checking every possible angle. There is no broken Leaf spring center Bolt and all critical components leaf spring perch leafspring center pin top plate and you bolts cinched down to correct spec. It all looks great now go for a drive return to the shop and it’s AFU. It is time to retire to dreamland and perhaps receive an epiphany from truck designers in heaven. Signed me mildly depressed good night. Iran trail rated Toyota trucks with 63 inch Chevy rear spring packs with consistent 1000% reliability and consistency and performance. How is this now such a train wreck applying that technology under a CJ?

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post #13 of 42 Old 06-14-2021, 09:00 AM
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What does it do if you disconnect the shocks and swaybar? You said that putting it up on the lift, letting the suspension droop then everything returns to straight, then it gets all shifted over after a short test drive correct? Are you running a traction bar of any sorts?

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post #14 of 42 Old 06-14-2021, 01:23 PM
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When the problem occurs, does the Jeep lean like there is more arc in one spring pack enough to upset the geometry? Have you tried switching springs right to left to see if there is any difference.
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post #15 of 42 Old 06-14-2021, 02:56 PM
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Quote:
Originally Posted by 80cj View Post
Have you tried switching springs right to left to see if there is any difference.
That's what my suggestion was going to be.

Are these orbit eyes intended to be used with a panhard bar?
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