Shackles Inverting at Full Droop

While crawling on the John Bull trail in Big Bear last weekend, my front driver's side shackle inverted (flipped inward and up) when my suspension was maxed out at full droop. I know that this is not an entirely uncommon problem in the Jeeping community, but I don't ever want this to happen to me again. I'm going to be making several modifications up front, one of which is to fab up some stops that I can weld onto the spring hangers or frame in order to prevent the shackles from flipping too far up. Has anybody here tried that? If so, I'd be interested in seeing the pictures. I've also heard of folks running boomerang shackles up front so that the middle support bolt will act as a stop. I'm not planning on doing that, but I am curious if anyone here has tried this with any success. If so, I may consider it. Just for reference, I've got a '72 CJ with a YJ spring conversion. I've got the Old Man Emu heavy-load springs with Currie shackles.

 

You could probably locate some anti-inversion shackles --- the ones that OME supplies with their leaf spring kits. These work great and are greasable.

 

You could add a bump stop to limit the travel of the shackle. Place it so the end of the spring hits it, not the shackle. I had to do this to a utility trailer 10-15 years ago. Still working fine.

 

Limiting straps bolted onto the shock mounts could work.

 

I've got a M38A1 with a YJ spring conversion. It also has the Old Man Emu heavy-load springs. I did use the shackles came with the kit. I haven't had this problem yet. Do you think you mounted the plates in the wrong spot?

 

To start with, a shackles length can dictate overall travel, both droop and compression. Stock YJ jeep leaf springs sit pretty flat with the load of the jeep on them, not so with lift springs since they have a larger arch in order to provide that lift. Since lift springs are designed to bolt in with no changes to the mounts, the eye to eye dimension of the spring is the same as stock, but with the additional arch, the main leaf of the spring pack is actually quite a bit longer. So, in order for a lift spring to compress all the way to being flat, the eye to eye dimension is going to be greater than the stock spring. If the shackle is not long enough to allow this to happen, the spring will bind before it gets flat..........the reverse of that on droop is if the shackle is not long enough the arch of the spring will try to pull it (shackle ) towards the frame.......hit a rock or solid object during that event and they invert.

Not knowing how your shackles were set up angle wise or what lengths you have more than likely they are too short...........notwithstanding that most lifted springs should require that (at ride height weight in compressed ) the fixed end on the chassis may or will probably need to be moved to accommodate the longer main leaf and also to properly get the shackle in the right starting position angle..........that position or angle forward on front mounted shackles is around 15-20 degrees on new springs assuming they will soften and settle into something less than 35-40 degrees ...........sounds complex, but not really......jack your jeep up and support it with stands under the frame while the suspension hangs....cycle it with a floor jack the picture will start to get clear what you need to do to fix it.

 

I didn't actually buy a YJ conversion "kit" per se; rather I bought the springs, built my own hangers, and bought Currie shackles (which don't have an anti-inversion provision). To be honest, I didn't know that anti-inversion shackles were sold by OME for Jeeps, so I learned something new there. While I've seen these shackles before, everyone I've seen has actually had them mounted on backwards thinking that they are tow-bar provisions, similar to Currie's tow-bar shackles. The OME anti-inversion shackles are more than $330.00, which seems a bit pricey for shackles. It seems like another option could be to put boomerang shackles on with the short leg towards the frame which would allow the middle support bolt to serve the same purpose as anti-inversion shackles. Quality boomerang shackles are only $100, so the savings would not be negligible; providing they function correctly. Longer shackles would also help, but they also come with associated issues such as digging into rocks and altering caster angles slightly. I believe however, that shackles are only a part of my problem/solution. Ever since going with the OME springs, my CJ has been super flexy; too much so. I had to put a Dakar extra leaf in each of the rear spring packs (which made a huge difference for the better), and I will be doing the same up front in order to stiffen things up a bit. At full articulation my calipers make slight contact with my Bilsteins and my front driveshaft also makes slight contact with my bellhousing. If the extra leafs don't alleviate this situation, then I will be adding limiting straps; although I kind of hate to do that. The following picture shows shackle angles at moderate articulation. The right side shackle is pulling inward as that side droops and the left shackle is pushing forward as that side compresses. I believe the angles seem to be in spec. All the input was and is appreciated, and I'll post how everything works once the modifications are complete.

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Now that I'm done fixing the shackle inversion issue, I figured I'd review what I did and post some pics. Hopefully, it may be of help if anyone else should ever have this issue.

First off, if anyone is considering doing the YJ spring conversion on a V8 CJ with Old Man Emu spring packs, you should definitely plan on putting a large add-a-leaf in all four spring packs. Without the add-a-leaf, the spring rate of the packs is simply much too soft. This caused problems for me such as scary body roll, clearance issues as the suspension cycles, and spring shackles inverting. The final straw for me is when my front shackle inverted and I actually bent the main spring (photos below). Here's what I did to resolve my problem:
-Purchased new spring pack to replace damaged unit (OME CS014F). This is the front heavy-load pack.
-Purchased long add-a-leaf (ARB D23XL) for each of the spring packs.
-Purchased Currie Boomerang shackles. Flipped them upside down so the middle support bolt will prevent them from inverting like an anti-inversion shackle.
-"Massaged" my custom spring hangers to build a pocket for the support bolt to recess into as the suspension droops.

After flexing the ol' CJ out in the rocks yesterday, I believe I'd call this job successfully completed. I love the way it rides with the add-a-leaf, and I know it will never again invert a shackle. Photos are posted below.

My old spring pack with the bent main spring is shown on top. The bottom spring pack is the new unit. Notice the front spring packs only come with four leaves. Adding a fifth leaf makes a huge difference for the better.

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This photo shows a good comparison of running a standard front shackle vs. running the boomerang.
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I had a do a little grinding in the spring hangers in order to "massage" a step for the center bolt.
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This is the boomerang at about static ride height.
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This is the boomerang shackle at what should be full droop. You can see how the support bolt will prevent the shackle from rotating any further.
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The next photos show the Jeep flexed out a bit.
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very nice looking Jeep. Been there, done that on the inversion topic. I used the CS036R all the way around on my conversion. They are the same length as the CS014F, but are 5 leaf and have a higher spring rate. The CS014F is too soft especially for a V8 equipped Jeep.

 

CSO14F is too soft for a V-6 and a big winch. I had to order a add a leaf.

 

I've never understood why the CSO14F's are listed has heavy duty and the CSO36R's are listed as medium duty then. Anecdotally speaking, my 36R's on the rear of the Jeep, were so soft that I had an add-a-leaf in them after my first couple of drives.

 

The 14F is listed that way because it's the only front option "technically" speaking. It's also the light load spring for the front- Only the spec'd lift height varies between the two. If you look around on a lot of forums, most opt for CS036R all the way around and sometimes an Extra leaf added in too. The difference between the CS037R and 36R is only arch, the rate is the same. The 14F has a taller arch but much softer rate than the other two. For most trail jeeps, a 36 or 37R is appropriate on all 4 corners with potentially adding an extra leaf if needed..... IMO. =)

 

Nice work. That Jeep is awesome.