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New shackles not straight?

10K views 16 replies 11 participants last post by  barrypicker 
#1 ·
I just finished installing some new 4 inch shackles from Crabtree Tool. Excellent quality and easy to order. The wierd thing is now that they are installed the both seem to kick out to the sides. Is this normal or is something else bent? Opinions or suggestions?



 
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#3 ·
Did you change any of the other spring mounting points?

The shackles will point laterally outward at the spring if your mounting points from the frame to the axle to the shackle aren't inline with the frame.

As an example:
1) If your springs are mounted 27.5" apart at the frame (spring eye)
2) If your springs are 28" apart at the axle perch
3) The shackle's frame mount is 27.5" apart.
4) Your shackles will lean outward (the springs will be about 28.5" apart at the shackle)
 
#7 ·
+1
Also snug everything up nice, while on jackstands and TQ to spec while it has its' own weight on it. I don't even know if it matters, but it looks like MAYBE some nuts are run down the bolt more than others, but that could be my bad eyesight. The nuns warned me about that! :laugh:
Also check to see if the grease fittings are facing in the easiest direction to service. W/O looking at mine, or better yet ANYBODY elses,....I can't say yours are wrong.
Good luck, and let us know how you make out.
 
#8 ·
The next thing I would do is loosen up all the bolts and remove the center brace, then retorque and see what it looks like. . The center brace length being incorrect is the only thing that makes sense.. I have the same thing only made by M.O.R.E and mine look straight.

One m ore thing. Did you install the metal sleeves in all the bushings?
 
#9 ·
The next thing I would do is loosen up all the bolts and remove the center brace, then retorque and see what it looks like. . The center brace length being incorrect is the only thing that makes sense.. I have the same thing only made by M.O.R.E and mine look straight.

One m ore thing. Did you install the metal sleeves in all the bushings?
No sleeves in these bushing, the bolt shank is 1/2" dia, larger than the stock setup.

I have the same shackles and found the center sleeve to be a bit too wide for the brand of bushings I was using (Daystar maybe?). I don't know if there are differences between brands or what the original shackle design was measured for, but for the time being, I left the sleeve out and just installed the center bolt. Did the same thing as everyone has mentioned and jacked it up, loosen u-bolts, snug the bushings, retorque u-bolts. Seems a little better, but I have not put a lot of miles on it since then. I need to beat on the suspension a bit and see where it sits after that.
 
#11 ·
zillla said:
I can see the problem in the pic below which I got from Crabtree's site. w/o the sleeve the bushings will collapse if tightened too far.. I am not impressed with this design..
That would have nothing to do with the problem. The issue the OP is having is that the shackles are leaning laterally like so /-/......not that they are bowed (-).
 
#12 ·
I don't think you've done anything wrong. What I notice is that the ends of the shackles are drawn in more than the center. I've seen this is some stock hangers and some springs, they're actually narrower than the center brace. If you're careful you can grind the center brace off a bit to take care of that problem.

The lean could be several things. Several customers have had that and found that the hanger itself was not sitting on the frame flat or that the frame was bent where the hanger bolts on. That's pretty normal. Hard to fix right though. Another thing to try, as has been mentioned, is to loosen the u-bolts and see if the weight of the CJ will settle them onto place. You may even need to push or pull the spring into alignment.

Another thing that is common is that the hanger itself is twisted. This seems to be the most common. New hangers are the fix for this, not new factory ones though and there's some good aftermarket ones being made too. In going back and looking at the pictures some more I think the springs need moved towards the center of the axle to better align things. I'd try that first. You have any long clamps that would reach from each spring to the other? You won't be able to move them much because of the spring pack bolts that extend into the spring perches but there might be enough play there to help the problem. It won't take much there to make a bigger difference at the end of the spring. Springs can twist too. Oh and take a tape measure and measure the outside distance on the springs where they mount of the stationary hangers then check at the spring perch and the then the shackle end of the spring. All three should be the same and from the pictures you post they don't appear to be.

Hope that's helpful
Jim
 
#13 ·
If you think that is not straight, just wait till you're flexing on the trail haha. Yeah I can see where the one side is kicked out more than the other. Thats caused by either a shackle twisted, or spring perches too far apart - they they kick outboard on the leaf spring end. I see you tightened down the leaf spring side a little too much on both. Oh well, check your shackle mount for any issues and if all is well then don't even worry about it - non issue. Actually it looks like a fairly decent setup they sold you. The nylon locking nuts will help keep every thing together.

I went with good ole rubber bushing instead of poly. Rubber gives, poly don't. I want as much flex as I can get, even at the expense of having to replace the rubber bushings more frequently - they don't last as long as poly. I'm going for max flex. It all depends on what you are wanting out of your rig.
 
#14 ·
So I took the center bolts and sleeves out and retorqued the ends. Then I went for a short drive and found a hill I could flex it on in both directions. i also loosened all the shackle bolts and used a ratchet strap to pull the springs together just a hair. I retorqued everything leaving out the center bolts and it looks like they have straightened up some. i reinstalled the center bolts and sleeves and retorqued everything. We've got a trail ride this Sunday that'll really break them in so I'll look at how they are lining up after that.

Thanks for all the suggestions guys, I'll keep you posted.
 
#17 ·
Did you resolve this? I am having the exact same issue. I have measured the distance between left and right sides at the rear mount point (Frame) to be exactly 27 inches, the middle (Axle perch) to be 27.75 inches , and front (Shackles) to be 27.875 inches and flared out.

For proper fitment it seems all mount points should be the same distance apart.

I am beginning to wonder if the axle perches have been modified from stock. I expected the axle perch separation distance to be the same as the rear mount points on the frame. If the axle perch mount points were widened it would cause this condition. If the mount points at the rear (Frame) is bent inward it could cause this condition. In both cases the only options for fitment would be the leafsprings bend laterally (unlikely) or the shackles flair out to compensate. Given the shackles are held in place using polyurethane bushings, it is likely the bushings give way before the metal leafsprings bend laterally.


Does anyone have factory measurements of the axle perch distance between left and right, and/or the rear mount point distance?
 
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