4bangerjp.com

General Forums => The Mess Hall => Topic started by: DiGGeR77 on March 01, 2009, 04:42:51 PM

Title: 4 link suspension on YJ
Post by: DiGGeR77 on March 01, 2009, 04:42:51 PM
This probably belongs on Member projects, but I never got a answer with a previous post.  I'm highly considering installing a 4 link rear suspension on my yj. I've been tossing around the SUA, SOA upgrade, but the whole 4 link looks like it would solve all the problems. It would give more flex, smoother ride, I wouldn't have to mess with the whole 'track bar' issue to make it pass inspection, parts are relatively inexpensive, doing coil or coil over would be the only big expense. Fabrication isn't a problem, and heck I'm already doing an axle swap, what better time? I was going to keep the front SOA for now (i think). Please comment on this post, if you know anything (pro's or con's) about 4 link setups!
Title: Re: 4 link suspension on YJ
Post by: FourbangerYJ on March 01, 2009, 08:47:07 PM
4 linking will cost more than you realize. Good joints, tubing, threaded rod ends, brackets, coils or coil overs it all adds up.
Getting the geometry correct can be a problem too if you have not done this before.
Title: Re: 4 link suspension on YJ
Post by: aw12345 on March 01, 2009, 08:50:53 PM
Would it not be better to 4 link the front? Seems like most people like a lot of flex up front, keeps it from getting tippy. You leave the front with springs it will rock from side to side a lot, you kinda want to try to get eaqual flex front and rear so the body stays fairly level IE doesn't roll side to side to much while the axles follow the terrain.
Atleast that was my goal and after a bunch of work and some add ons it actually does pretty much just that
Still want to add a currie rear anti rock swaybar and that's it for my little put put.
Title: Re: 4 link suspension on YJ
Post by: Jeffy on March 02, 2009, 03:11:27 AM
I've seen some older Jeeps running SOA front and 4-link rears.  They produce 70-80% of the total flex from the rear as a result.  They look sort of awkward.  I think the prefered setup is to have a bit more flex from the front so the tires can pull the rear up.  There are a few DIY weld-together kits out there.  I think Gen-Right has one.

Like what FourbangerYJ said, getting the geometry straight is key and not easy.  Screw it up and your suspension will try to eat itself.  Some use CAD then build a small model before going to the real thing.  It's really a case of measure twice, cut once as parts are expensive.

Still, it's probably the ultimate suspension out there.  Although I would not discount a custom set of SUA leafs, a SOA setup or some combination of both. (front SOA/rear SUA).  Custom leafs will make a HUGE difference as they are built to your Jeeps specific needs.

Now, if you really wanted to link the rear, I'd consider chopping out the frame at the rear then constructing a new rear frame with tubing.  This will give you a flat area to work with.  Also, consider that the rear will really limit how big of a coil-over you can use.  Most of the time it's best to cut holes into the frame and add hoops to allow for the proper length coil-overs.  Otherwise you'l have to run the coil-overs further forward to run a triangulated setup or some combination.

For research, check out http://www.pirate4x4.com.  The forums there are not really noob friendly so do a lot of searching.  If you do your homework and ask appropriate questions, you should get some really helpful info from them.
Title: Re: 4 link suspension on YJ
Post by: Bounty Hunter on March 02, 2009, 07:33:25 AM
I think it'd be easier and perform better to link the front, the frame is narrower and coilovers can be outside the framerails.  Keeping the rear slightly stiffer than the front will make a more stable and predictable jeep offroad.
Title: Re: 4 link suspension on YJ
Post by: Jeffy on March 02, 2009, 11:58:53 AM
I think it'd be easier and perform better to link the front, the frame is narrower and coilovers can be outside the framerails.  Keeping the rear slightly stiffer than the front will make a more stable and predictable jeep offroad.
I agree.  This is the premise for the SOA(front) SUA (rear) setup that many people as well as I run.
Title: Re: 4 link suspension on YJ
Post by: FourbangerYJ on March 02, 2009, 04:07:54 PM
What type of wheeling do you plan on doing?

Can't you just put the track bar back on before your inspection then take it off afterwards?
Title: Re: 4 link suspension on YJ
Post by: Mr_Random on March 02, 2009, 05:15:18 PM
I agree.  This is the premise for the SOA(front) SUA (rear) setup that many people as well as I run.

Does soa allow more axle flex than sua?

How does the YJ frame compare to the TJ frame? Simplest solution (if it works), would be to chop off and swap over TJ components and use an XJ HPD30, methinks, But that isn't necessarily the best solution for flex and lift height.
Title: Re: 4 link suspension on YJ
Post by: FourbangerYJ on March 02, 2009, 06:04:08 PM
Does soa allow more axle flex than sua?


Yes, since you use a flatter spring. Less arch = more flex.
Title: Re: 4 link suspension on YJ
Post by: jfrabat on March 02, 2009, 06:11:17 PM
In my opinion, the nice thing about leafsprings is the simplicity; if you move to 4-link, yes, you will have better flex, but you will also open a whole can of worms.  Are you sure the extr flex is worth all that complication?  If it is, go for it, but if not, think twice before starting that project.
Title: Re: 4 link suspension on YJ
Post by: DiGGeR77 on March 02, 2009, 06:18:26 PM
What type of wheeling do you plan on doing?

Can't you just put the track bar back on before your inspection then take it off afterwards?
Well here in pennsylvania, we got greasey clay, hills, hills, hills, deep creek beds, fallen trees, slate dumps with huge was outs, and the rock crawl'n we do have is wet and slimey! I thinking on doing SOA front and back, then once complete (and my funds replenish) I'll use that for my ride height and convert it to 4 link front and back. That way i don't waste money on lift springs or beafier springs, I'll be able to get all the bugs out, before I get more problems from the 4 link. Does that sound like a good idea?
Will taking off the trackbar with stock springs running D44 & 35's be a problem? I'm fairly sure I got new stock springs om my jeep.
Title: Re: 4 link suspension on YJ
Post by: Jeffy on March 02, 2009, 06:59:47 PM
Seems like it will be a waste if you go SOA then go to link front and rear.  Really though, if you're going to go through all that trouble, sell the Jeep and build a buggy from scratch since that's what you'll end up with eventually anyway.  I've seen many friends chop up their Jeeps till nothing was left then sell the junk and build from the ground up.
Title: Re: 4 link suspension on YJ
Post by: FourbangerYJ on March 02, 2009, 07:33:51 PM
Well here in pennsylvania, we got greasey clay, hills, hills, hills, deep creek beds, fallen trees, slate dumps with huge was outs, and the rock crawl'n we do have is wet and slimey! I thinking on doing SOA front and back, then once complete (and my funds replenish) I'll use that for my ride height and convert it to 4 link front and back. That way i don't waste money on lift springs or beafier springs, I'll be able to get all the bugs out, before I get more problems from the 4 link. Does that sound like a good idea?
Will taking off the trackbar with stock springs running D44 & 35's be a problem? I'm fairly sure I got new stock springs om my jeep.

If you do SOA F&R make sure you put on a antiwrap bar on the rear. You will toast the springs and driveshaft U.J's in a hurry.
Personally I would not link it. I love my leafs. I am not running trackbars or swaybars. I have not for years and years, I drive it everywhere. Not a single problem or concern. Not sure if you needed them for your state inspection.
Many people run the stock springs SOA. They don't last long unless you add a extra main leaf. Since you only want to run 35's the stock springs should give you plenty of lift to clear them. The Full Traction zero lift springs look good too. I don't know of anyone running them but they look like a nice spring. But the best leafs are the custom ones Deaver or Alcan.
Title: Re: 4 link suspension on YJ
Post by: Bounty Hunter on March 02, 2009, 09:19:58 PM
Leaf springs flex pretty good, and they're stupid simple.  KISS is good.  I run stock leaf packs plus an extra main leaf SOA.
(http://i237.photobucket.com/albums/ff110/PepperJeep/MoonInTheBoonies/Moon6.jpg)
Title: Re: 4 link suspension on YJ
Post by: FourbangerYJ on March 02, 2009, 09:35:30 PM
Leaf springs flex pretty good, and they're stupid simple.  KISS is good.  I run stock leaf packs plus an extra main leaf SOA.
(http://i237.photobucket.com/albums/ff110/PepperJeep/MoonInTheBoonies/Moon6.jpg)

Looks good.  :nod:
I agree with keeping things simple!
Title: Re: 4 link suspension on YJ
Post by: DiGGeR77 on March 03, 2009, 05:20:02 AM
Well, it looks like the more I know, the less I know  :flush:
back to SOA!
Title: Re: 4 link suspension on YJ
Post by: TahoeYJ on March 03, 2009, 10:38:55 AM
I've thought many times about linking my YJ (Which if I ver do, is a LONG ways from now...)

My D35 started making noise this weekend, and I've already rebuilt it and geared it once, so I really don't want to spend sny more on it. I've got a Ford 9" that's been sitting for over a year in my garage and after some research, I've found it won't take as much $$$ as I thought to build it like I want. So I'm seriously considering a SOA set-up in the rear when I get it in, and keeping the front SUA until I have the time to set it up. Sucks because I just spent $180 on my DS yesterday to have it more or less rebuilt, so now I've got to spend even more to have it lengthened if I go SOA  :pirate:

I've seen lots of SOA YJ's and CJ's and they seem to wheel pretty damn good IMO. The ride quality is better than my SUA set-up too :)
Title: Re: 4 link suspension on YJ
Post by: Jeffy on March 03, 2009, 12:45:34 PM
Well, keep in mind that when people say SUA, most of the lifts out there aren't that good.  The only two worth installing is the OME 2.5" and the Rubicon Express Extreme 4.5".  Other then that, you would want to look for something custom like National Springs, Dever, Alcan, etc...

Otherwise, if you want to go SOA, do a lot of research on leafs.  Personally I like my SOA/SUA since it's a good median between articulation and driveability.  No axle wrap either.
Title: Re: 4 link suspension on YJ
Post by: Jesse-James on March 03, 2009, 02:54:19 PM
I am very happy with the SOA/SUA combo on the road, almost no body roll with the sway bar in use. If it was my only DD I might keep it that way but the offroad ability is too lacking. 4 link rear is underway and a radius arm front will probably happen next year.

Articulation was pretty poor.

(http://i68.photobucket.com/albums/i33/jlafaive/ramp.jpg)
Title: Re: 4 link suspension on YJ
Post by: FourbangerYJ on March 03, 2009, 03:06:29 PM
I am very happy with the SOA/SUA combo on the road, almost no body roll with the sway bar in use. If it was my only DD I might keep it that way but the offroad ability is too lacking. 4 link rear is underway and a radius arm front will probably happen next year.

Articulation was pretty poor.

(http://i68.photobucket.com/albums/i33/jlafaive/ramp.jpg)


3 or 4 link the front, radius arms are not the way to go. They bind to much. Causes problems in the long run with broke/tore brackets plus they don't flex as well as the 3 or 4 link.
Title: Re: 4 link suspension on YJ
Post by: Jesse-James on March 03, 2009, 03:14:50 PM
I got plenty of time to figure out the front, just thought radius arm for streetability and an easier build. Four link fronts are a PITA to put together.
Title: Re: 4 link suspension on YJ
Post by: Jeffy on March 03, 2009, 03:20:49 PM
I am very happy with the SOA/SUA combo on the road, almost no body roll with the sway bar in use. If it was my only DD I might keep it that way but the offroad ability is too lacking. 4 link rear is underway and a radius arm front will probably happen next year.

Articulation was pretty poor.

(http://i68.photobucket.com/albums/i33/jlafaive/ramp.jpg)

Looks like the rear leafs are too stiff.  That driver side rear doesn't look to be flexing at all.
Title: Re: 4 link suspension on YJ
Post by: jagular7 on March 04, 2009, 01:53:44 PM
If you want a radius design arm for the front, look into Cage Offroad's SAS kit  (http://www.cageoffroad.com/solidaxleswap.asp) for the Ford TTBs. I've got a Duffy design radius arm I'm going to use when and if I install the front D60. Duffy's you have to weld on the 'C' cups on the axle and use the rubber isolators to adjust your caster. Cage's you weld on the preset location.

img]http://www.cageoffroad.com/images/solidaxleswap/F2F1_200.jpg[/img]


It is non-adjustable for caster but I think it could easily be mod'd similar to the TJ's setup. You have a keyway bolt with a cam on it. The cam rotates against an edge and you tighten it once you dialed in your caster.
(http://www.cageoffroad.com/images/solidaxleswap/F2F1_200.jpg)

BTW, the frame end has a heim as big as my palm.....
Title: Re: 4 link suspension on YJ
Post by: Jesse-James on March 04, 2009, 02:14:56 PM
Looks like the rear leafs are too stiff.  That driver side rear doesn't look to be flexing at all.

They were, after wheeling a few times and adding new 6 leaf packs to the front it wasn't much better. So 4 link it is.