Stumped. Rear Shackle Flip

**SJTD** · 07-28-2019, 02:54 PM

If I'm understanding your question the stiffness of the the spring keeps it from continuing back. The spring still has to compress for it to extend and the shackle to move.

The advantage of having the shackle pivot ahead of the spring eye is you get a lower effective spring rate.

The disadvantage is you can limit travel. If the spring wants to compress more and get longer but the shackle has moved to where its two bolt holes are in line with the front spring bolt you have a problem. The spring wants to flatten out more and get longer but the shackle won't allow it. Major bind.

I'd install it so the shackle is vertical or a little past with the vehicle sitting on the springs. Got some clamps? Should be able to clamp the hangers to the frame to get the position right.

**Rusty76** · 07-28-2019, 07:02 PM

Ok thanks for the reply. I think I've got it?
I assumed the shackle to bracket bolt was loose so it could swing front and back. That's not the case. You torque that bolt down enough so it will hold the weight of the body up. Keeping the shackle angle at around 45 degrees with the body weight on it. When you hit a bump the spring flexes pushing the shackle out a few inches before it comes back to fixed position....

Man, does my explanation even make sense? Sorry if I don't reply right away. Just heading out on a 3 day rafting trip/ Jeep sabbatical.

**SJTD** · 07-28-2019, 11:09 PM

Seems like you were wondering about the shackle should be able to move with the bolt tight.

If you had urethane bushings it would move. With standard rubber bushings it shouldn't. The rubber is vulcanized to the sleeve which is held tight by the bolt squeezing the mount against the sleeve.

This is why you want the vehicle sitting on the wheels before tightening the the spring and shackle bolts. It puts the rubber in an unloaded condition in the normal riding position.

I'm wondering about the 45 degree thing. Where'd it come from? Why?

**Rusty76** · 07-29-2019, 05:38 AM

Morning.. The 45 degree shackle was just a general guess after its all bolted
Like this pictures. up.http://i998.photobucket.com/albums/a...ostest0001.jpg

As of right now both rear springs are bolted in the front and cut in the back.
the old shackle bracket are gone. the body of the wagoneer is basically sitting on those rear spring. sitting on its wheels.

So by tightening the shackle to bracket bolt it will hold the weight of the vehicle but still allow it to move that little bit once the spring is flexed.

thanks again

**bufurd** · 08-07-2019, 01:29 PM

My opinion that pic is not how I would mount it, like said earlier, vertical (back a little bit okay) with the vehicle weight on it is how I'd roll. What you don't want is with the weight off (axle hanging) for the shackle to swing forward enough that it could lock forward.

**Rusty76** · 08-10-2019, 12:50 PM

I agree. I've been looking and chatting a lot about the flip. I'm hoping to get this done next week. Pretty nervous about drilling into frame. Really going to take my time mocking it up. Thanks for the help.

**rang-a-stang** · 08-12-2019, 04:27 PM

I think the real angle you want is with the weight of the axle hanging on the spring, the shackle should have a tiny bit of a downward angle. If the shackle and spring go straight under full droop you will have a good chance of the shackle flipping upward when you the axle comes back up and getting jammed into the chassis.

just my thoughts.... can anyone correct me?

**bagusjeep** · 08-14-2019, 12:50 AM

With full droop (i.e. jacked up and dangling) the line between the shackle eye, spring eye and spring should not be straight.

If you did, it would be 50/50 which way it would go when you loaded it back up. However, there is another effect which is that as you approach vertical, the shackle is jacking up the weight of the jeep and this can lead to a wild ride.

The closer you get to 180 degrees, the greater the impact of a small further droop in the axle. I suggest you keep it below 90 degrees just because of the handling characteristics.

On compression the angle would be well below 90 degrees. I suggest keeping this above 35 degrees.

If your range of movement is between those parameters, you should be safe from flipping the shackle or binding the spring or getting strange handling characteristics. It just takes a bit of levering and measurement to check you have it in the right position.

**wiley-moeracing** · 08-14-2019, 03:33 AM

get 2 4x4 blocks of wood, about 12" long, jack up the rear off the truck so the springs are unloaded and have a gap to slide the blocks of wood in. Position the blocks so when you lower the truck back end down, the springs have enough room to slide the eyes backwards and still be on the blocks of wood. Lower the back down so the full weight is on the springs. Mark where the center of the spring eye is on the frame rail, this will be your starting mark where the shackle mount should be. You will be able to hold the spring mount up to the frame and locate it so you can see where the shackle will be angled, shoot for a 35- 45 degree angle rearward(depends on your load and use), you will have room for the swing loaded and unloaded. Mark you bolt holes and drill it and then mount them. Make sure both sides are the same, you may have to move one side or the other to make them match. simple and easy.

**Rusty76** · 08-14-2019, 07:43 AM

This is a huge help thanks everybody! I'm just about to get started on replacing the front leaf bushing and shackles. After that I will tackle the rear. I will be sure to update this thread. Thanks again.

Quick question. When I move to the back shackle hanger replacement does a guy need to remove the shocks or can I leave them in and replace at a later date?

Thanks!

**Rusty76** · 08-22-2019, 01:49 PM

Hello; Ok so I got my shackle flip done but of course something is not adding up.
(Shocker)... Anyway my angle I believe is ok but the old springs are basically flat.
Prior to the shackle flip I did purchase the original shackles. Maybe I need to use those. They are a little shorter compared to the ford ranger shackle and hanger set up. I have not torqued all the bolds yet. Are my springs just so old and worn that they are flat and I need new ones? Learn as you go! That is the truth!

Sorry for the dark pics.

IMG_9980 by , on Flickr
IMG_4176 by , on Flickr

**SJTD** · 08-22-2019, 02:41 PM

Shackle angle has very little to do with the spring curvature. They'd have to be way past 45* before you'd get any "wedging" effect that would cause the springs to flatten out when just sitting.

The shorter shackles might get you a little height since they'd sit more vertical but not much if any.

I don't like the angle, seems too much but if the springs are sitting flat they're prolly ok. Should be pretty good if you get new springs of the same length with some arch.

Howzit ride?

**rang-a-stang** · 08-22-2019, 02:43 PM

How does it look when the axle is hanging?

**Rusty76** · 08-22-2019, 03:11 PM

Thanks for the quick reply Rang. Here is some pictures with the axle lowered.
Much more spring arch and I would say shackle in a better position.
So does this mean the old springs are shot and I need to replace?
Thanks everybody.

IMG_5117 by , on Flickr IMG_5534 by , on Flickr

Stumped. Rear Shackle Flip

Stumped. Rear Shackle Flip

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