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View Full Version : Rear shackle flip without moving spring eye (pivot)?


BostonWagoneer
04-02-2002, 12:47 PM
I know this topic has been beaten to death, but I couldnt find a straight answer to this in my searches.

I have some CJ-style shackle hangers left over from a Wrangler project and I could just weld or bolt those onto the bottom of the rear shackle mount and remount the spring with CJ-style shackles pointing downward.

This is WITHOUT moving the front eye bolt of the spring. The pivot will be in the same place.

Will this work or does it change the pinion angle too much?

I will be using stock springs and a slight block if necessary. The front will be SOA with stock springs.

Thanks!

EDIT:

What is the maximum working angle for a 1310 ujoint? Is it about 20º ?

I just threw this together in Inventor to show what I am talking about. The angles dont represent real angle values, but they are there to show that the u joint angle is not 0 (which would be indicated by 180).

The circles represent the axle position. The lower one is after shackle flip. The ends of the lines at the far right is where the spring bolts to the shackle, so the distance between them represents the distance that the shackle flip has moved the spring eye downwards.

The two lines that meet at a point (center of the ujoint at the transfer case) on the far left are the two driveshaft scenarios. The top one is before shackle flip.

The other point where two lines come together on the left/middle is the main spring eye pivot. This stays the same before and after shackle flip.

The short line coming out of each circle represents the pinion. The angle of the pinion to the spring is the same before and after (because I am not moving the perches).

I hope this explanation makes sense smile.gif and my drawing is simple enough.

I have another complex drawing that has all the angles and distance relationships, I just have to measure my Wagoneer for the right dimensions to input. (if interested: http://www.jeepjunkies.com/boston/misc/shackleflip.jpg )

http://www.jeepjunkies.com/boston/misc/shackleflip2.jpg

[ April 02, 2002: Message edited by: BostonWrangler ]</p>

BostonWagoneer
04-04-2002, 04:02 PM
Anyone?

jeepbob
04-05-2002, 04:35 AM
I run a shackle flip on the rear of my 65 without moving the front pivot point. I also have stiffened the rear springs by adding a couple of exter leaves to the spring pack. I have not had a u joint problem since I went from a strap style yoke to a u-bolt style yoke on the rear end. In the past I had twisted out a few joints due to straps flexing and allowing the cap to be spit out. I am running home made (shortened) driveshafts that have been some what balanced on a lathe and still do not have a vibration. Either I am really lucky or even better than I thought :D I have and can use several different design programs but do most of my stuff from plans in my head. This seat of the pants engineering is way old school and obsolete because it calls for a little common sense (very little in my case) and has no place in the modern design world.

graham
04-07-2002, 01:28 AM
BostonWrangler, Check out the link below, it shows how I did what your trying to do. I gained nearly 4" of lift at the axle. This has been tested many times since it was done with no ill effects as yet.

Shackle Flip. (http://www.geocities.com/ozbearhunter/suspension)