4 link rear suspension

I recently bought my first XJ and have had a blast ever since.I converted from an auto to a manual and added a (semi homemade) 4 in. lift. I was wondering if anyone had specs or a diagram of how to build a 4 link rear suspension?I have done one four link on a fullsize ford that worked alot better than stock but without a real frame to bolt to i am slightly confused.could a partial frame be added to the xj's unibody?I am a good welder and ok fabricator,should i just wing it?help?

What most people do to add support to the "frame" is to weld 3x3 angle iron, or cut a side off of ?x? box tubing and slip that over the unibody rails. As for the 4-link, cant help ya, im an old-school leaf spring kinda guy :wierd:

go to pirate4x4.com and search for "god of suspensions" and "links for dummies" read each 4 times. Biuld your 4 link. Drive it for a month. Realize you screwed up, rebuild and be happy.

Four links are cool.



Leaf springs work really well on the rear of XJ's.

I tried the "god of suspension thing with no results......i want some more flex from the rear,I have awesome spots to flex on my ranch.I was thinking about taking out a leaf from the spring packs.....it worked on a fullsize for me but i dont know the rate of the XJ's springs.Is this a feasable project?

TwiztedXJ said:

I tried the "god of suspension thing with no results......i want some more flex from the rear,I have awesome spots to flex on my ranch.I was thinking about taking out a leaf from the spring packs.....it worked on a fullsize for me but i dont know the rate of the XJ's springs.Is this a feasable project?

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You can get quite a bit of flex out of leaf springs, if that's all you're after. If the bind is removed, the shackles are long enough and positioned properly, and the spring clamps are the right type, they'll flex nicely. Nothing wrong with a four link if that's what you want to do, but it won't necessarily work better, and it's a ton of work to do.

Removing a leaf would add considerable spring wrap, unless you already have aftermarket springs that are too stiff.

Goatman said:

...and the spring clamps are the right type...

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Care to elaborate?
Billy

I built a subframe then tied the suspension to it, with a 4 link rear, you will have to figure out the stress the links will have at the angle you decide to go with, also the more angle or distance between the upper arms will give you less rear steer, you will also need to learn about the anti-squat figure, you should search pirate4x4 for 4-link, and anti-squat. You need to know all this before you figure out how you will mount it to the unibody (thats the easy part). You will also need decide if you are going to run coil springs, or coil-overs, once you decide on what type of spring, you will need to figure out the spring rates and lengths, also if you are running a stock axle you will have to build mount across the pumpkin for the upper arms, it should also wrap around the rear for better support. YOu will not have much room to build a mount because of the gas tank. so you will need to go high in the lift to clear it when you are pressing the rear down. You can check this link, http://www.pirate4x4.com/forum/showthread.php?t=183879
I remove the pictures when I decided to sell it as a kit, I have know just decided to donote my research and knowledge, I am in hte process of doing a complete write up on the build up of creeprs. You can email me at [email protected] for more info

That was an awesome setup.Similar to what iwas thinking about.....but MUCH sturdier.The only problem i think i will encounter will be the geometry of the links. Or do you have any measurements offhand? And how does it work? Also....i have looked into the front leaf swap on another site...Does anyone have this done and does it make a difference in articulation?Better/Worse?

the geometry is fine as long as you understand the amount of stress that is put on each link and stay with in the specs of the hardware you are using. The measurements will be differant then mine depending on how you set it up, just remeber the longer the links the less angle, the more rear steer.

TwiztedXJ said:

...i have looked into the front leaf swap on another site...Does anyone have this done and does it make a difference in articulation?Better/Worse?.....

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Twiz, do you KNOW what you really want? To ask about how to do a 4 link rear and then consider a leaf spring front is SUCH a contradiction.

Why do you want links over leaf springs is the first question to ask yourself. Do you know why?

Are you able to understand and willing to spend many many many hours researching the geometry?

Are you willing to build your suspension many times? Can you cut it off when it doesn't work & rebuild it?

This isn't a bunch of BS my friend, I spent the better part of 6 months building what I thought was a kickass front 3 link + TB, it didn't work so I modified it some, it didn't work again, I went back on POR & spent 3 days of my vacation reading, LITERALLY! Then I cut off my front suspension for the 3rd time. Finally after many hundreds of hours of work I have a great working triangulated 3 link front suspension that works as it should and I like it very much.

If you can't answer the above questions, dont do it. Build up off the stock suspension until you have some reasons for the mods you want to do.

.02

-jb

Ditto what Vintage said.

Leaves in back, and you want a four link. Four link in front, and you want leaves. WTF? :huh:




BTW, in case you hadn't noticed, the front coil/rear leaf of the XJ work extremely well, with reasonable modifications. Make up your mind what you want the rig to do for you, and there's plenty of info/experience around here to get you good information.

Oh, and to answer your question, guys put leaves in front because of the simplicity, not because they work better......because they don't work better. Some put in leaves because they are easier to understand, rather than figuring out how to fine tune the four link or converting to a three link or radius arms. (might have started something with that comment)

Thats funny,and, Really is the reaction i expected but was hoping not to get.As far as the leaf question,it did seem wrong to me,but i thought "hey maybe i missed something".just wanted to get all the questions out of the way before i go head long into a very drawn out project.BTW,Yes i have the time and am willing to build over and over again.and again.I was looking for someone who had some measurements they would give up to get me started.And since it was mentioned the factory four link is respectable,but where can i find parts for upgrades,Or will i have to fab them up myself?Or,do you have any pics of your three link?I have never dealt with them and it sounds like you are pretty impressed with yours.Just want to get ALL the questions i can out of the way,and ANY help would be gtreatly appreciated

Twisted, I have some excel documents, that will help you figure out angles and stress loads of the arms at differant angles,

The three link wishbone, is not really that much more differant then a four link, if done correclty,

shoot me an email offline to [email protected] to remind me to send the document to you, I have a couple of them, giving you differnat information, the first will give your 4 link cacls, it allows you to play with the lengths of the arms and see how much stress is applied on the end link. This comes in real handy for setting up the 4 link, you do not want to overload the end links and just throwing something together from someone else's measurement may be bad for you. Ex. I can give you all my measurements but because I built me a frame to go under it, they would be differant on a unibody. My framerails measure 32.5" inside to inside and total wheel base is 8" longer then stock. Do not use somebody elese measurements get down with a tape and measure. I built a jig out of pvc, to simulate my suspension, a lot cheaper then rebuilding your arms, over and over. measure your frame rails inside to inside, all the way down the frame or after the transmission x-member if you are only wanting to change the rear, then build your a model of the frame from wood, a few 2x4's will work, and buy some 1" pvc tubing, then build your suspension the vehicle with this using the documents, I will send you. I will work the first time, mine did.

my opinion is this:

if you aren't willing to cut link tunnels in the floor of the xj, don't bother doing a 4-link. leaf springs work just fine.

if you don't understand why, keep reading/learning/searching.......

TwiztedXJ said:

Thats funny,and, Really is the reaction i expected but was hoping not to get.As far as the leaf question,it did seem wrong to me,but i thought "hey maybe i missed something".just wanted to get all the questions out of the way before i go head long into a very drawn out project.BTW,Yes i have the time and am willing to build over and over again.and again.I was looking for someone who had some measurements they would give up to get me started.And since it was mentioned the factory four link is respectable,but where can i find parts for upgrades,Or will i have to fab them up myself?Or,do you have any pics of your three link?I have never dealt with them and it sounds like you are pretty impressed with yours.Just want to get ALL the questions i can out of the way,and ANY help would be gtreatly appreciated

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Many companies offer aftermarket control arms, coils, trackbars, even subframes and complete suspension kits that will give you a great suspension for everything you want to do.

Rubicon Express, Skyjacker, Currie Enterprises, JKS, and many more.

You can wheel the hardest trails in the country with conventional XJ suspension.

Once you've mastered that & found the shortcomings for what you want your Jeep to do, then build something custom. You really need to know the basics before you jump into advanced suspension geometry 101.

But if you persist to build your own, do yourself a favor & learn about what you're doing on POR. You'll need to know what all of these are before you proceed (and much more): Instant Center, Roll Axis, Anti-Dive/Lift, Link separation, torque loading, your c.g., calculating spring rates, 1/4 1/2 3/4 elliptical springs, rear suspension unloading, spring wrap, etc etc.

Once you've got the basic stuff down you can find what you need to know to build your own link suspension. OR you can just jump into it and build what you think is right only to find out later on how wrong it was, usually after it's broken and taken other parts with it. Good luck.

-jb

vintagespeed said:

Once you've mastered that & found the shortcomings for what you want your Jeep to do, then build something custom. You really need to know the basics before you jump into advanced suspension geometry 101.

-jb

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exactly.

Oh come on. Those who jump head-long into projects they don't fully understand are the most fun to be around!
They take the pressure off of those who are testing stock type mods when we are on the trail (while you remember to tighten those bolts you installed last night...everyone else is trying to get them thru the section of trail you just cleared)
I have yet to encounter any situation that I felt I needed some exotic suspention to overcome.
I still don't mind watching those who know what they are doing...be it fabrication or driving.
And I also enjoy watching those who think they know what they are getting into ! :rof:
Rick R

WoW!This is going better than i thought!Not only have i realized i don't know crap,but now i realize it takes alot of reading and research to know just a little crap.Anyhow,everyone has helped a ton.As far as pirate4x4.com goes,Do i need a membership to search the site and does it have a price?When i try to search it says i dont have the privelage.I filled out the page it sent me to but i still cant search.Is there a price for the membership?It seems like EVERYONE has sent me there at one point or another,and i would really like to pick it apart.

i know a couple years ago you didn't have to sign up to be able to search, but they may have changed that. signing up is free, just like this site, and you can become a member with more priveleges for a few bucks. do lots of searching and reading before posting, and when you do post, HIGHLY consider doing it in the Newbie section.