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Unread 12-30-2013, 09:43 AM   #16
Spieg8
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I ran a shackle reversal on my (okay it was my x-wife's) CJ7 for several years. Ended up taking it off after that. While it did seem slightly more stable on the highway, it also had a few peculiar issues that I wasn't able to overcome.

1) The upper shackle mount at the rear of the front springs was bolted through a hole in the frame (similar to the rear shackle of a YJ). In order to get decent spring travel, it required super long shackles or else the spring eye would hit the frame. The extra leverage created by the long shackles seemed to eat bushings quite often which would allow the inner shackle to rub the frame (was actually grinding away the frame near the bottom). Perhaps other reversal kits use a different mounting system, but I can only comment on my experience.

2) As mentioned before, it did brake awkwardly. A panic stop at highway speed would sometimes cause the Jeep to handle unpredictably (an emergency stop in a CJ is always a white knuckle affair, but even worse with this modification).

3) Because the axle shifts rearward when the springs flex (a conventional shackle setup will have the axle shift forward), the trailing edge of the front tires would tend to rub on the fender when driving over axles. This should be possible to overcome with custom made fenders (larger opening), and/or by moving the whole front suspension (and steering box) forward. It was just more modification than I was willing to put into that Jeep.

4) Even though the lift height was the same as it was with conventional shackle setup, I had to get a new front drive shaft with long travel slip joint. Couldn't understand why it started eating u-joints until someone told me the standard slip joint travel was being exceeded when the suspension compressed.

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Unread 12-30-2013, 09:49 AM   #17
Matt1981CJ7
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Quote:
Originally Posted by Spieg8 View Post
I ran a shackle reversal on my (okay it was my x-wife's) CJ7 for several years. Ended up taking it off after that. While it did seem slightly more stable on the highway, it also had a few peculiar issues that I wasn't able to overcome.

1) The upper shackle mount at the rear of the front springs was bolted through a hole in the frame (similar to the rear shackle of a YJ). In order to get decent spring travel, it required super long shackles or else the spring eye would hit the frame. The extra leverage created by the long shackles seemed to eat bushings quite often which would allow the inner shackle to rub the frame (was actually grinding away the frame near the bottom). Perhaps other reversal kits use a different mounting system, but I can only comment on my experience.

2) As mentioned before, it did brake awkwardly. A panic stop at highway speed would sometimes cause the Jeep to handle unpredictably (an emergency stop in a CJ is always a white knuckle affair, but even worse with this modification).

3) Because the axle shift rearward when the springs flex (a conventional shackle setup will have the axle shift forward), the trailing edge of the front tires would tend to rub on the fender when driving over axles. This should be possible to overcome with custom made fenders (larger opening), and/or by moving the whole front suspension (and steering box) forward. It was just more modification than I was willing to put into that Jeep.
I take it you didn't squabble over who got to keep that rig.

Matt
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Unread 12-30-2013, 09:55 AM   #18
swatson454
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There's got to be some missing element here. There are millions of Ford and Chevy trucks with the shackles in the rear that behave just fine under hard braking. I wonder if the shackle reversal needs a rethink in pinion angle or something. I suppose that could cause the front end to turn into a shopping cart under hard braking.


Shawn
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Unread 12-30-2013, 10:06 AM   #19
Matt1981CJ7
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My thinking is, if the reversed shackle were truly a better setup, then why didn't the AMC engineers go that route on all CJs? There certainly wouldn't have been any manufacturing cost difference.

Believe it or not, they did have vehicle safety testing in the '80s. I can only conclude that the standard shackle setup was determined to be the safest most functional setup.

Matt
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Unread 12-30-2013, 10:12 AM   #20
swatson454
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Originally Posted by Matt1981CJ7 View Post
My thinking is, if the reversed shackle were truly a better setup, then why didn't the AMC engineers go that route on all CJs? There certainly wouldn't have been any manufacturing cost difference.

Matt
You're not trying to suggest that AMC is known for their engineering prowess are you? From where I stand, Jeeps already have "reversed" shackles


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Unread 12-30-2013, 10:18 AM   #21
Matt1981CJ7
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Originally Posted by swatson454 View Post
You're not trying to suggest that AMC is known for their engineering prowess are you? From where I stand, Jeeps already have "reversed" shackles Shawn
Granted, the AMC engineers may not have been at the top of their class, but they were engineers, nonetheless, which most of us aren't.

It always amuses me when shade-tree mechanics think they know better.

Matt
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Unread 12-30-2013, 10:24 AM   #22
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I used to work underground with an old-timer who always said "I'd rather have a daughter in the whore house than a son who's an engineer"


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Unread 12-30-2013, 10:28 AM   #23
Matt1981CJ7
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Originally Posted by swatson454 View Post
I used to work underground with an old-timer who always said "I'd rather have a daughter in the whore house than a son who's an engineer" Shawn
You don't keep the brightest company, do you?

Oh wait...I think I just dissed myself.

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Unread 12-30-2013, 10:40 AM   #24
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Originally Posted by Matt1981CJ7 View Post

You don't keep the brightest company, do you?

Oh wait...I think I just dissed myself.

Matt
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Unread 12-30-2013, 11:14 AM   #25
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Ok, I've done a few panic stops in my CJ since the frame swap w/reversal. The nose dive isn't much of an issue to me as the poor braking. I don't notice any issue with the steering while in a panic stop any more than every other vehicle I've driven and had to do panic stops in.

Drive line modification wasn't needed with mine, as I stayed with stock springs. I guess if you have a lift which allows more travel before hitting bump stops you may have to worry about the slip joint length. I have had the front tire rub on the trails, but I am also running 31's with approx 1" body lift. The tire was rubbing the bolts for the charcoal can bracket. I reinstalled them with the head towards the tire and nuts under the hood and that helped that issue. This was only happening on a good flex obstacle and the wheels turned to the left.

I will say mine was done to the frame when TDK built it. I had to use YJ shackles on the springs and spacers since I am using CJ springs which are narrower than the YJ springs. The width of the frame requires the YJ springs, but since I had already bought the CJ springs I am using them for now. If I ever have to replace the fronts I'll go with YJ next time. I am using poly bushings in the front, so hopefully I won't have to worry about the shackle/frame issue as mentioned above.

Other that the nosedive issue, which I also had with the flat, worn out, OEM springs just not as bad then, I don't notice any other ill effects from the reversal. It drives much smoother now since the swap, and the steering is much more improved, but there was too many changes done at once to say what one thing it was to improve it. New frame (old rusted out behind steering box), new HD steering box mount (old one was cracked away from one bolt, missing one bolt, one bolt loose where washer fell out, and the fourth was the only one tight), New springs (old were sagging flat or worse), and poly bushings in the suspension. Either way, it handles just as good as my 88 Ranger does. Even in panic stops.
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1978 CJ5 258/T177/D300, '86 D30/D44 WT axles, 'glass tub windshield frame, and fenders, 31x10.5 BFG A/T, TDK galv'd frame - DD and weekend toy

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Unread 12-30-2013, 07:05 PM   #26
skizriz
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Quote:
Originally Posted by swatson454 View Post
There's got to be some missing element here. There are millions of Ford and Chevy trucks with the shackles in the rear that behave just fine under hard braking. I wonder if the shackle reversal needs a rethink in pinion angle or something. I suppose that could cause the front end to turn into a shopping cart under hard braking.


Shawn
I would imagine the stiffer springs have something to do with it.
Under braking the forces compress the springs, and also try to shove the axle rearward. With a front shackle setup, the compressing spring pushes against the forces trying the shove the axle rearward (axle moves forward as spring compresses).
With the rear shackle, the force pushes rearward, and the shackle helps it along as the spring compresses and the axle also moves rearward..

Stiffer springs, less compression, less shackle movement. Add together the combination or rear shackles, soft springs, and the extra leverage of SOA, I could see how it would want to pin the shackles against the frame under hard braking.
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Unread 01-05-2014, 12:08 PM   #27
O1dSoldier
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Hi Folks,

I'm in the process of planning a rebuild of my '78 CJ5. I recently picked up a frame from a local salvage yard the specializes in Jeeps and it already had a shackle reversal installed although I'm not convinced that the reversal kit actually is the right one. That said, I have a couple questions.

1. Is there a way for me to calculate how much extra lift, if any, this kit may have? I already have a lift kit (springs only) on the jeep that I will reuse and should I decide to keep the reversal kit on the frame it will be important to know any additional lift so i may need to compensate for.

2. Without any identifying marks I have no idea who the manufacturer is of this kit so am wonderig if there is anyone here who may recognize it.

Thanks folks.
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Unread 01-05-2014, 12:36 PM   #28
toads
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I have the MORE kit on my cj7. I am running the wider YJ springs. My springs are 4" skyjackers. On road the difference in handling is a huge improvement. Yes i do get some nose dive during really hard braking. I did move my axle forward with some offset spring plates that MORE makes. That helped keep the tires out of the fenders. I then had to move the steering box forward 1 inch also. MORE also has a steering box bracket for that. I wheeled mine lots before I changed to the shackle reversal. I folded the shackles backwards a couple time now I dont have to worry about that. I always destroyed my shackle bushings. I still destroy them but it takes a few more wheeling trips to do. I would say go for it. PS the guys at MORE are awesome.
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Unread 01-11-2014, 11:29 AM   #29
bldmncj
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Originally Posted by toads View Post
. I did move my axle forward with some offset spring plates that MORE makes. That helped keep the tires out of the fenders.
Can you post the link for that offset spring plate. I also have the same set up as you do on my 81 and i love it. The only thing i don't like is the front tire pushes back when climbing major obstacles.
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Unread 01-12-2014, 12:51 PM   #30
toads
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http://www.mountainoffroad.com/_e/Of...ings_OP_25.htm
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