Okie.. heres the dilema.


I broke a leaf eye on my rear main passanger side.

So.. I got new springs to swap in.

The new springs... are millitary wrap.. and 4 leafs with an inverted 1/2" thick leaf on the bottom.. (I assume to control heavy loads, and extreme flex.) (lots of load, the big leaf contacts and stops sag)

I was going to pull the big (1/2" leaf) and rebuild the pack so it was just like the old one.

Only..

I just pulled the old leaf on the drives side out to get ready to put the new one in.. and looked at them.. then got the tape measure..

The leafs are the same length and the right leafs, only my stock YJ with an adda leaf are 7" from the ground to the spring.. when they are upside down..

The new ones are 6".

So I'm going to sit one inch lower right?.. BOOO..

Plus.

With my Amazing 170 lbs :P.. I can make the old spring sag to 6, 3/4" that's a 1/4" flex..

The new springs I can make sag to 5,1/4..

that's 3/4" flex..

So, I came to the conclusion that these new springs are flexier.. (duh).. so with some rough guesstimation... I can conclude that they will sit somewhere between 1" and 2" down...

Also, the old springs were just pulled, where as the new ones were not on a truck for a whiile with weight on them..

Ok if anyone is still reading this pat yourself on the back.



Conclusion:

My Jeep is going to sit, somewhere between 2-3" lower at the rear end then it used to.

Solution:

I have 6" shakles.. and my new springs are 4 leafs not 6..

I'm guessing a SOA would give me 5" of lift.

So, I could go 2-3" lower... or.. if it is 3" lower, I could go SOA, chop 2" from my shakles, giving me 1" of lowering power at the axle.. and finally equal a lift of 1".

Right?


Anyone care to check my math.. this is all theoreticall.. I'm going to load the springs to morrow and see where I am..






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I also just wanted to check.

SOA, longer break line.. (the one between the frame and axle)
vent tube (needed doing anyways.)
anti-wrap bar. (I can handle this and it can be an inprogess project.
SYE.. this is my big one.. Theoretically.. it would be like adding a 1" suspention lift to my current config... do I need a SYE? if so.. how mcuh... and then I need a special driveshaft too right?



This is only the rear end. so no steering or other complications..

Anyone got any insight.. hints..

Can I do this?
I've done carb swaps, fabbed my rollcage.. and installed OBA.. am I way out of my league.


Any info is greatly appreciated.

Thnx guys.

If you read this far you either are very bored or have a very boring job where you sit infront of a computer.

Holy Crap!!! What a post.....

Anyhow, I read most of it. Definitely ditch the shackle lift and go SOA. It should be easy on the rear, and you aren't really lifting the Jeep more than it already is(1" doesn't count, it will probably sag). So, shocks and brake lines should work. Just replace the shackles and weld some new spring pads on top of your axle. You may have issues with spring wrap. Those can be addressed with a traction bar later.

Later,
Tom

Thanks for the info...

I'm going to set it up SUA first and then go SOA if there is a need.


I had a question about the SYE and CV shaft..

Anyone got a good webpage that goes over this setup/project.

a CV shaft will lesten my driveline vibrations..?

and the Slip Yolk provides the travel in the rear right now... if I get a SYE.. then the travel is in the Driveshaft not the Slip Yolk?

Im a little confused are you planning on doing this to the front also? If so its going to sit a little funny. Also are you figuring your total lift based on 170 lbs load per spring? If it was me I would lose the shackle lift altogether and find a complete set of springs that serve your pupose better. Either stock springs with the spring over or springs with whatever lift you desire.

No, the front would remain SUA for now.. until I eventually went SOA and redid the front end to match.


This is sarting to become damage control just need to fix it time..

The 170lbs per spring is the most I can administer.. I don't have another way of testing how they flex.

I assume it will be much higher.. 2-3X the weight per spring when they are loaded into my Jeep.

Right now I have two options it seems.

When I put it back together and see that I'm 3-4" lower then I used to be I can:

A) Try to scavange as much lift as possible from MORE shackle extentions, add-a leafs,and other undesirable methods to make up3-4"

or.

B) Go SOA in the rear and instead just try to bleed 1".. if necessary through the more desirable shorter shackles, and more spring flex due to less arch/less stiffness.

If it is only the main leaf that broke in your old spring, you may be able to take one or two of the leaves out of the old springs and add them to the new spring pack. All you may need is some longer center bolts.

Someone with more spring experience can chime in now and tell you why my idea won't work, since this seems too simple. [img]images/graemlins/grin.gif[/img]