TJ rear suspension

Okay here’s my first question , let’s see how bad I get beat up …

I have researched pro’s & con’s on doing this and have decided at this point it will be in my best interest all around. As mentioned in my welcome post while driving I’m putting my life in jeopardy at any speed over 40mph due to the poorly set up and worn out rear lift.

As far as what I am going to be doing with this jeep (use) and my budget the best way for me to correct my rear steer happy TJ is to go with a leaf suspension in the rear. Most all will say it’s going backwards but it will serve my needs and wallet perfectly.

Question I have is I have seen a lot of people use XJ front springs and go with a SOA app. I am trying to get as close to the same height as the front is currently. From what I can tell it has a 6" rough Country lift on it now so I am aiming for a 6" lift in the back from stock. I would rather go SUA so I’m thinking a leaf spring for a 6" lift should get me in the ball park and I can fudge it from there if need be with shackle adjustments to even out ride height with the front.

Any thoughts on what I should use for springs lol

:open_mouth: :open_mouth: :open_mouth:

Drop it all down 2 inches. I think 6 is too much for a TJ.

If you do decide to do a SUA you may need 8" leaf springs as the front 6" lift is measured form the top of the axle to the Jeep, and the SUA will me measuring lift from the bottom of the axle to the Jeep? I would think the lift you are loosing from having the axle hosing on top of the spring would mess with the dimensions? Gene will be able to chime in on this.

I agree with Derick, get shorter coil springs in either 3" or 4" lift and lower it. Going with leafs will involve a lot of welding and fabrication unless you can find someone who makes a kit to do this…

Ya dropping the TJ is the better option.

I wouldn’t recommend leafs myself…

What exactly is wrong with your current lift?

It probably be cheaper to fix what you got.

The problem with the current lift is it was gaffed in. The links ‘were’ adjustable but they cranked them all the way in to get as much pinion angle as possible. Once they got that far they welded the threads on the links. Either that or in time they stripped out and welded them. The angle is just all wrong and due to it the rear springs are bowing like banana’s because the spring perches on the axle are about 20 degrees tipped back from level. On top of it due to the high lift & short arms the stability left to right is awful thus giving me rear steer with every crack in the road. The shocks are hitting the lower spring perches along with the exhaust pipe. The track bar is up against the gas tank, one of the shock mounts is broken on the frame so they welded the shock to the body :open_mouth: . The spring mount plates on the frame are all rotted and need replacing also. It would be just as much work if not more to fix what’s there now than going to leafs. A long arm kit would solve this or a lower lift kit as mentioned also. If I go lower an entire kit is needed as the front links are also welded costing about 1K+. Same deal if I go with a long arm set up in the rear alone or fab up a 4 link. And if I go that route I still need to address the mounting points of the coils, track bar & upper links on the frame. Leaf springs,hangers,shackles,u bolts,plates & perches will cost me about 400 on the high side. I can fab & weld so no cost there except for paying the electric bill. The 600 left over will come in useful and let be able to fix other issues it has to get it safely on the road.

I realize leafs are a step backwards and do not flex,articulate or ride like coils do. But a properly set up leaf suspension will out perform a poorly set up link suspension everytime. For what I am looking to do with it I dont care about the ride (if I did I wouldnt have bought a jeep lol) or the off road flexibility as it will be 90% on road & 10% off. Just for laughs check out this link 4x4wire.com/jeep/tech/susp/tjleafsprings/

I put a string along the bottom of the frame rail from the bumper to the tranny pan where the perches for leafs would be. The top of the axle is 6" from that & the bottom at 8". Between the front spring hanger and the shackle on the rear that will drop that measurement another 2" if I went with leafs. So ‘in theory’ it seems a 4" spring in a SUA app after it sags from weight would sit the axle right about where it is now. Like I said , at this point it’s all about the wallet & getting this thing on the road.

Down the road I want to do a long arm 4 link in the rear. It’s probably just about the same amount of work I’m looking at now. Once I get the jeep squared away I will return to the suspension. Just looking for a short term patch at this point to keep moving forward as much as possible.

I talked to rubicon express today for some measurements. A 4" spring has a 9.5" arch , the next down would be a 2 1/2" spring that has an arch of 7.5. Funny thing was the guy in tech told me he’s had plenty of calls on the same exact thing so glad to know I’m not the only wack job out here !! He felt the spring for the 2 1/2 lift paired up with shackles about an 1" or maybe 2" longer than stock (depending on how I mount them) would be pretty close to where I need to be. Thinking about it now I can see where a leaf meant for a 2 1/2 lift will be a lot more stable then what I have now to end up with the same amount of lift.

Do what I did when my truss and upper control arms from Rock Krawler wore out. Buy some DOM tubing and rod ends and bungs and find someone that can weld. Drop the jeep to 3-4" of lift and you can get a full set of control arms custom made for a lot cheaper than a new lift

I’m just finishing a trip at Rausch two YJs and a xj plus my tj one YJ is 4 linked in the back and never lifted a tire more than a few inches. The xj and other YJ with leafs kept lifting tires in off camber climbs due to the leafs not flexing as well as coils. I had no issues with lifting tires with my long arms…

X2 bad rod ends would cause a lot of your issues. Billing New links is pretty cheap and easy

Lucky for me I’m in no hurry or need for the jeep and my free time is all but nill right now. After checking more things out and poking around more (and input from here also) I’m going to rebuild the short arms I have. If I can get the weld off without screwing up the links to bad I’ll replace the adjustable ends with johnny joints and put new bushings in the other ends. If that fails I was looking into a RC kit that sells both the upper & lower arms all together for 700$.

My front track bar is adjustable but the one in the rear is not. Should I have an adjustable one in the rear or doesnt it matter as I’m not changing the height its at as of now. I’m assuming it’s a fixed length for the lift or adjustable for a one does all for various lift heights . I have to replace all 4 shocks (relocate the rears for clearance) and the links one way or another so all will be new & tight. I figured while I’m up there I might as well change out the rear track bar also. What is the better option for the rear ? They all the same using stock locations or is there a better way to set it up ?

Sorry for all these bonehead questions , just dont want to end up with a pile of useless crap that doesnt work if I dont have to.

dont waste the money on a

$700 kit. buy DOM and rod ends/heims and you are out of this for a lot less $$!!

You don’t have to.

What’s your end game? If you are in this sport for the long haul and plan to spend significant time on the trail then your best investment is Clayton Offroad.

Absent that, converting your existing arms to use genuine Johnny Joints and Clevite bushings sounds like a decent approach. However at that point you might as well just build new arms from scratch.

There is no way the stock rear track bar would work with 6" lift. Mostly likely there is a bolt-on bracket at the top or bottom. I guarantee that bracket will break sooner rather later if you wheel the rig. At a minimum it should be welded in place.

I would go with a adjustable bar in the rear so you can get the rear to track properly. It is easy enough to make one from a stock bar.I have also made them out of two of the bushing ends from the stock front bars.