Correcting shackle angle on post mount (pre 76) rear shackle flip rigs using 76 and up springs?

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Nikkormat
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Correcting shackle angle on post mount (pre 76) rear shackle flip rigs using 76 and up springs?

Post by Nikkormat »

I've been reading up on shackle flips for the rear of my jeep for a couple of days now as an option for gaining height economically but have hit a wall at crappy shackle angle creating a rough ride. My understanding is that after flipping, the rear shackle will be pointed towards the front of the vehicle, making the ride much harsher.

But after thinking about how to correct that shackle angle for a good long while I remembered that the rear portion of 76 and up springs are a couple inches longer! So, could I use 76 and up springs to correct the rear shackle flip angle? Would the two inches be enough or would I need extended shackles to to make the angle more pronounced? Has anyone done this?
Last edited by Nikkormat on Sat May 30, 2015 11:19 am, edited 1 time in total.
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Re: Correcting shackle angle on post mount (pre 76) rear shackle flip rigs using 76 and up springs?

Post by Nikkormat »

I'm also wondering how well the flipped shackle will control axle movement compared to stock. Would axlewrap be worse with flipped shackles? Is there any dangers to the drive train after shims have been installed to correct pinyon angle?
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Re: Correcting shackle angle on post mount (pre 76) rear shackle flip rigs using 76 and up springs?

Post by Nikkormat »

OK, here is what a shackle flipped post mount rear end looks like. Image
A longer spring would correct the shackle angle, right?
It should also be noted that this picture is at static ride height.
Last edited by Nikkormat on Sat May 30, 2015 11:44 am, edited 1 time in total.
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Re: Correcting shackle angle on post mount (pre 76) rear shackle flip rigs using 76 and up springs?

Post by Nikkormat »

KaiserMan wrote:Here is a cut and paste from a post made by Laher Spring Company on FSJN.

Wagoneers

"1962-73 Wagoneers use 22 x 22 x 2 1/2 inch front springs with 9/16 ID bushings on both ends, and 26 x26 x 2 1/2 inch rear springs with 7/8 ID bushings on the post and 9/16 ID bushings on the shackle.

1974-75 Wagoneers use 22 1/2 x 24 1/2 x 2 1/2 inch front springs with 9/16 ID bushings on both ends (the same as 1976 up), but 26 x 26 x 2 1/2 inch springs on the rear (the same as 1962-73). The kicker on the rear springs is that they have a 1 inch post mount instead of a 7/8 inch like the 62-73's - same spring - different bushing. The shackle bushing is the same 9/16 inch ID.

1976 and up Wagoneers use the 22 1/2 x 24 1/2 x 2 1/2 inch front spring with 9/16 inch bushings on both ends, and a 26 x 31 x 2 1/2 inch rear springs with 9/16 inch ID bushings on both ends. "

Trucks

"1962-69 trucks use 22 x 22 x 2 inch front springs with 7/8 inch post mounts and 9/16 inch shackle bushings, and 26 x 26 x 2 1/2 inch rear springs with a 7/8 post mount and 9/16 shackle bushings.

1970-73 trucks with a 119" wheel base use the same front spring and the 26 x 26 x 2 1/2 inch spring with a 1 inch post mount and a 9/16 inch shackle bushing.

1970-73 trucks with a 131" wheel base use the same front spring but a 26 x 31 x 2 1/2 inch rear spring with a 1 inch post mount and a 9/16 inch shackle bushing.

1974-75 trucks with a 119" W.B. use a 22 1/2 x 24 1/2 x 2 1/2 inch front spring with 9/16" bushings on both ends, but a 26 x 26 x 2 1/2 inch rear spring with 1 inch post mount and a 9/16 inch shackle bushing.

1974-75 trucks with a 131" W.B. use 22 1/2 x 24 1/2 x 2 1/2 inch front springs with 9/16 inch bushings on both ends and 26 x 31 x 2 1/2 inch rear springs with a 1 inch post mount and a 9/16 inch shackle bushing.

All 1976 and up trucks use 22 1/2 x 24 1/2 x 2 1/2 inch front springs with 9/16 inch bushings on both ends and 26 x 31 x 2 1/2 inch rear springs with 9/16 inch bushings on both ends.

All of this assums that your truck has rubber factory bushings. If your truck has brass bushings, well, that's another ball game. It seems as though the Jeep engineers set out to drive the aftermarket guys crazy. "
So I may need new bushings, but aside from that it should be a slam dunk eh?
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Re: Correcting shackle angle on post mount (pre 76) rear shackle flip rigs using 76 and up springs?

Post by Nikkormat »

If im guestamating correctly full droop with the springs 3-4 inches longer on the back end should net 90° at full droop, 60°-70° static, and 40° at full compression. My time lurking in Toyota forums in that past tells me that those numbers should both ride and flex well. Right? Am I crazy or might this work?
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Re: Correcting shackle angle on post mount (pre 76) rear shackle flip rigs using 76 and up springs?

Post by ghcoe »

I did a shackle flip on my '72 Wagoneer and it road better than stock. I had a spring shop re-arch the front springs and they added a helper spring that sat right under the main leaf full length. I never had to correct for axle angles and I did not notice any ill effect. Heck, I did not even know about those things back then. No vibrations and steering felt no worse than at stock height, ride was better, life was good till it got hit by the semi.......but that is another story.
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Re: Correcting shackle angle on post mount (pre 76) rear shackle flip rigs using 76 and up springs?

Post by Lumpskie »

FWIW, my stock shackle angle was almost straight up and down on my rig. My yota is kicked back 45 degress (which I think of as "normal") but it's also a standard shackle mount from the factory.
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Re: Correcting shackle angle on post mount (pre 76) rear shackle flip rigs using 76 and up springs?

Post by Stuka »

Nikkormat wrote:If im guestamating correctly full droop with the springs 3-4 inches longer on the back end should net 90° at full droop, 60°-70° static, and 40° at full compression. My time lurking in Toyota forums in that past tells me that those numbers should both ride and flex well. Right? Am I crazy or might this work?
I don't even think you will be able to bolt those springs up without a shackle that is way longer. To use the stock shackle you only need a main leaf that is about 1.5-2" longer.

And using lift springs will move the axle forward because you are only lowering the rear mount, and not the front. Plus the horrible pinion angle you end up with. I had terrible drive shaft vibrations until I lowered the pinion down via a shim.
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Re: Correcting shackle angle on post mount (pre 76) rear shackle flip rigs using 76 and up springs?

Post by Nikkormat »

Well crap. There's never an easy way out is there.
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Re: Correcting shackle angle on post mount (pre 76) rear shackle flip rigs using 76 and up springs?

Post by carnuck »

How about this: Look up Riverbeast (sorry, I forgot the newer name as I've had a sinus headache off/on for almost a month now thanks to Cottonwoods) and see how the front part of the rear spring is mounted under where it was stock. Move it back 2" and Voilà! you have your extra length plus a sizeable lift with stock springs at the same time. It also "fixes" most of the pinion angle change.

found a pic

Image
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