I know some might consider it a step backwards, but has anyone considered a leaf sprung SFA swap? I'm thinking a high pinion Dana 44, front spring hangers welded to a steel front bumber and rear shackle mounts attached to a reinforced frame (or like an XJ's), TJ steering box, crossover steering, etc. It just seems cheaper and easier. Can anyone foresee any potential problems? I've always liked and appreciated the simplicity of leaf sprung vehicles.

Aside from the fact that you will have to replace the springs more often than coils, and that you wont get as good of articulation? No nothing really. Why go cheap the first time when you can go better?

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Richard~Mid Atlantic VA Rep.
NCBBA/Mid Atlantic Jeepers/UFWDA Member
Mid-Atlantic & Carolina LOST #236236
2006 TJ Solar Yellow Rubicon
Lockers, Springs, Skids, Headers, Snorkel,
Exhaust Work, 4.5 Long Arm, Warn M8000
315/75/16 Nitto Terra Grapplers Moab's/SpiderTrax, 6000k HID, IPF H4

In addition to cheaper, it's in keeping with the K.I.S.S. principle. The brackets are easier to produce, less areas to reinforce, less stuff going on equals more room to work with, etc. And although it wouldn't be as high-tech as a coilover setup, it would still be an improvement to the current suspension limitations and weaknesses. In addition, once either of the swaps is completed, you'll probably encounter a host of other issues particularly, with steering due to lack of design testing. The price difference could be in the thousands.

If you're gonna go SFA, I would think there would be a relatively inexpensive coil-over application for another rig you could adapt to the KJ. I totally dig the KISS principle, but why reinvent the wheel? Just playing devil's advocate here...

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04 Sport
L.O.S.T.#000574
Blue Maglite, Revos on spare rims, Fuzzy Dice.
Long Island/Vermont

Leaf springs are relatively easy to design. The main issue I see is that the Liberty is unibody...no frame to readily design spring mounts onto.

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George Reiswig
2005 Jeep Liberty CRD
Suncoast, SEGR, lift, InMotion tune, homebrew B100
At 138k, new head & gasket, timing belt, rockers and swearing vocabulary

Are you also going to convert the rear to leaf springs? Or are you going to have a leaf front and a coil rear? That'd be weird!

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KJ 2002, 3.7L Sport
Stuff | Pics
Lifetime Member # EJ062115

Rear could just be converted to a four-link. A little weird but not a first. I've seen a number of Wranglers set-up with front coils/rear leaves and others with front leaves/rear coils. Not sure what the train of thought was.

It would be an interesting project. I have built several stretched TJ's switched to leaf packs in the rear. Leafs are a lot simpler to setup, and using a leaf/coil combo is an excellent combo. I'm not just saying that because I am an XJ guy, but if you look at all the built rigs that have coils or coilovers at all four corners, they are (or should be) running antirock swaybars for stability and to "control" flex and keep the coils from unloading so easily. If I had a YJ Wrangler, I would convert the rear to coils and leave the front as leafs. XJ's and rigs that go coils in the front and leafs in the rear have a fairly blanced setup, but the problem is, the coils flex a lot easier than leafs, and all the weight is in the front, so the coils easily flex in the front, but the rear which is so light, has troubles flexing the leaf packs, meaning the leafs will usually fight the flex more. It's not that leaf packs don't flex, they just need the right amount of weight. Since the front of the jeep is heavier with the engine and tranny, and the rear is so much light with only a gas tank, and the coils will flex easily with less weight, it would make more sense to put leafs in the front and coils in the rear. Leafs in the front would flex great and maintain stability. So in short, I think it would be a great project. If I were to build a KJ, front leafs wouldn't be a bad idea, and I would definately comp cut the rear and stretch that rear axle back, of course there would be full width axles under there too.

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WWW.ROCKLIZARDFABRICATIONS.COM

i've seen on some other forums some real nice 1/4 elipse setups on ZJ's and such with some real nice pivot mounts...they get some SERIOUS flex, would that be feasible?

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"It's not stuck...it just doesn't want to move on its own..."

Silver 2002 Grand Cherokee Overland (Not running as of 12/30/2014. Suspect dropped valve seat)

White 2003 Liberty Limited (RIP)

L.O.S.T. #: DV053827

Well.... as far as it being less places to reinforce to do leafs I disagree. You would still have to do some sort of reinforcement for the steering gear. And where I was able to utilize the strength of the unibody where the struts originally mounted, the only other real reinforcement I had to make (which I overkilled) is behind the axle where the radius arms attach. With leafs you would still have to create the strength in structure for the front spring hangers as well as beefing up behind the axle for the rear hangers.

You would never want to do 1/4 elipse on a front axle for the reason that there is too much movement and the steering would have a hard time being able to match the axle articulation on the pivot points and arcs of the linkages, not to mention that it would probably wonder around like crazy (at least not for anything you desired to drive over 15 MPH).

I have done both coil and leaf SFA conversions and really the coil versions are only slightly more work, but greatly better outcomes.

To be my own anti-me though, there is no reason why a leaf SFA would not work on the Libby. And if more people try different things there will be more options out there and we'll get more notice and perhaps more parts builders will get ideas.

-Adam

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My Libby SFA Project

Question for you fab guys, how long are leafs typically? I mean I know on the old wranglers, the placement of the bumper seems to be dictated by the need to have front spring mounts way out in front of the axle. Is there enough overhang on the KJ to accomodate that? Or would you be hindering your approach angle?

Just curious...

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04 Sport
L.O.S.T.#000574
Blue Maglite, Revos on spare rims, Fuzzy Dice.
Long Island/Vermont

The XJ guys use old Wagoneer front D44 axles with the stock Waggy leaf springs. Anytime you use leaf springs, front or rear, you are going to hurt the approach and departure angles. Size of tire and lift height will have a big effect on the angles as well. I don't remember the length of the Waggy front leaf packs, but the rear XJ packs are about 52". I think the front Waggy leafs are in the low 40"s, but I would have to find one and measure. I would also have to compare measurements on a KJ to an XJ, but I don't think it would be much more difficult to do and front leaf conversion on a KJ compared to an XJ.

Jedi, I do hafta say........I wish my jeep looked like that! That is one bad mama jama! If I only had the money....but on the topic of that, how much did your SFA conversion end up costing you, minus your rims?

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<----DK050059---->

Ye Old Grocery Getter....
96 XJ 4Dr Stick <----The New Mall Crawler

another problem with leafs is the handling problems. I am not talking about ride quality on the highway, I am talking about what you lose in turning. Leafs like to get in the way of wheels especially on tight trails and u-turns.

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'02 KJ Sport V6 4x4
3/8" Clevis lift
Rusty's 2.5 lift
255/70/R16 Fleet Farm All Terrain (yes they work)
Class 3 hitch
Hellas
Police Scanner/CB radio
LOST #: JH061986

The XJ springs might be too long. I think Waggy or YJ springs are the way to go. I tore a CV boot so the KJ is deadlined! I'll be deciding in the very near future whether or not to proceed with my conversion, wait for a professionally developed conversion, throw more money away on my current debacle, or just sell or trade her in. I believe that regardless of which aftermarket lift kit you decide to purchase, the current IFS setup is so inferior that it's a moot point. Aluminum front diff, ball joints, CV boots and yes, even the unibody design that will need to be heavily reinforceed to support anything other that what it was initially designed for. What the f@$K, over? SFA, sell or trade-in! I've owned a CJ-5, 2 XJs and 1 FSJ. In addition to my KJ, I also own a WJ and a TJ. This is the first Jeep that I WOULD NOT recommend to an off-road enthusiast. What a POS! My apologies if my venting offends anyone, but it's true. I knew the KJ was going to be a challenge from day one but good Lord. That said, I do know that I would rather wheel and turn heads with a tricked out KJ than just blend in with another TJ. (Although that one's still running and hasn't posed any problems... knock on wood!). Seriously though, what a freaking headache. It's just one can of worms after another.

Go sfa

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'05 KJ Renegade 3.7L
stuff
Lost Member Number: 051898

What are your thoughts on tying in the front suspension to an aftermarket steel bumper like RL's or would I be better off with fabbing a cross member from box tubing. That's something else I'm concerned with, making mods which would hinder the installation of RL's front bumper.

I was thinking of doing the swap with a HP D30 from a YJ and keeping it SUA (KISS). A SOA could be performed later with more money. With wheel spacers it could be made to match the rear axle. I was also looking for a FSJ D44 to take WMS measurements, but right off the bat the bolt pattern is different. I guess you could upgrade the rear with a matching 44 from a good donor truck but then it would need a disc brake conversion, etc., etc.

I was planning on welding spring mounts to lengthy, 3/16ths steel channel and bolting it to the uni-body. Still looking at engine, tranny, & shackle clearance issues. I don't know if I could do a shackle reversal.

Wally, I read somewhere that you used a steering box from a Bronco II. Do you see any reason why a TJ steering box might pose a problem? I've already acquired one with a pitman arm.

Clint, what's the deal with the idea of flat fenders you tossed out a while ago?

RL,

Since you have a lot of experience with XJs and unibodies, what's your school of thought on reinforcing the frame for shackle mounts? Weld, bolt or both? I've attached 2, apparently different trains of thought. Please see the following excerpts.

ORGS' Steering Brace System:

"Laser-cut chassis plates are supplied for the inner and outer chassis rail, along with special sleeves that tie both plates together and provide additional support for the steering gear. The chassis plates and sleeves must be welded to the vehicle's chassis, as a bolt-on design could not possibly provide the same level of integrity and fitment."

http://store.jksmfg.com/merchant2/merchant.mvc?Screen=SBS&Store_Code=JKS01&Category_Code=Trackbars_Steering

Rusty's Long-Arm Upgrade:

Due to the thinness of the Jeep unibody, we've designed our long-arm kits to be completely bolt-on. Although it is possible to weld to the unibody, the longevity of the weld in questionable. The unibody is only 16 guage (.060 in.) and the heat of a weld stresses the thin metal. The weld may not crack but the unibody around it may. The unibody is welded from the factory, however, robot controlled welding is done complete with heat sensors creating welds much more exact than a human is capable of. Our bolt-on systems are not only more durable but are also much easier to install. Our clamped/sleeved mounting system uses 1”x3/16” thick tubes thru the unibody which creates a larger surface area that distributes any stress over a larger area than a weld-on installation.

http://rustysoffroad.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=rustys&Product_Code=XJLT1&Category_Code=sus_xj_kit

OK, I don't know if I will get your questions answered directly, but Ted and I have been discussing doing a front SFA leaf spring conversion on his junk. I have seen these conversions done on XJ's (though never preformed the procedure personally) and I have done several rear leaf spring conversions on TJ Wranglers, so I have a pretty good idea of what is involved, although the KJ will be a challenge with what needs to be removed of the IFS to be able to finish the procedure. The nice thing about leaf springs is the simplicity. No complicated suspension link geometry from running coils, plus the price would be about 1/3 of setting up a coil suspension. I can find Waggy front D44's all day long here and the pick and pulls for $100 complete brake to brake. I know guys that will do a bench top gear install for $150. Cost of D44 gears, about $120, plus cost of master install/rebuild kit, ARB air locker, your looking at about $1200 just for the front axle, front shocks and leaf springs, maybe $100. I'll have to look up the part number, but on the TJ conversions I have done, I used the leaf spring frame mount brackets for YJ Wranglers for about $15 each. Just need to build custom front shackle hangers, which could be tied into the bumpers mounts. Plating the unibody is a real good idea. My XJ front bumpers come with the unibody bracing/steering box reinforcement plates built into the mounts. I have a lot more measuring and research to do, but on the XJ conversions I have seen, they use the Waggy front leaf springs they picked up with the front Waggy D44, and they use the lower control arm mounts to bolt the rear of the leaf spring too, then the leaf springs line up with the spring mounts on the Waggy 44, then they just line up the front shackle hangers. Very simple conversion for XJ's.

The biggest obstacle with the Waggy D44 front axle is the bolt pattern, being a 6 on 5.5, and the rear KJ 8.25 being 5 on 4.5. I don't remember the WMS to WMS on the 8.25, but I'm thinking it is just under 60". The front waggy D44 is at 61.5". The waggys are often confused with the FSJ. They are not the same. I forget all the years available off the top of my head, but the easiest way to distiguish between the waggy and the FSJ, is the waggys were four doors. Stay away from the 83-84's as they mostly had the vac disco D44's. The FSJ's looked like the waggys, but they were only two doors and had wide fender flares. They had the D44's as well, but they were 64" WMS to WMS, so considerably wider. The AMC20 rear axles that usually came in the waggys were considerably stronger that the old CJ 20's, but the waggys got a bad rap being called the 20 due to the weak design of the CJ 20's. The rear D44 would be a great swap in to match the front, but then you run into the problem of the rear suspension geometry setup, which would have to be done on the swap in D44, then you loose the whole point to doing a cheap front conversion. The cheapest way I can think of to match the bolt patterns would be to get rear 8.25 alloy shafts with the 6 on 5.5 bolt pattern to match. I do believe you can change some front D44 components to make the front a 5 on 4.5 bolt pattern, which I will dig that info up here in a little bit. As for steering, I will have to look more at how the KJ is setup before I can even think on how to set that up.

More ideas. You could get an HPD30 out of a 97-99 XJ, cut all the bracketry off and weld on the leaf spring perches. That would be simple, keep the stock bolt pattern, and if you get the 97-99 D30, it is the strongest D30 available stock with the High Pinion setup, and has the 297 joints, which is the same as the Waggy D44. These D30's and the stock 29 spline 8.25 that came in the KJ and the late 96-01 XJ's are plenty strong enough from running up to 35" tires. I wouldn't even consider running a YJ D30 when a newer HPD30 or waggy 44 would be so much stronger, but very little more work. The other problem you run into when it comes to gearing is the limitations of the 8.25, which can only go to 4:56 gears, which is fine for 33's, but if 35's were ever a consideration, 4:88 gears would be most ideal, although it isn't that bad running 4:56 with 35's.

If I were to build a KJ tomorrow with an SFA setup, and only had a budget of about $3500, I would do the leaf spring front conversion with a late model HPD30 from and XJ, cut off all the brackets, weld on the leaf spring perches and shock mounts, get the front leafs off an old Waggy or YJ, YJ frame mount leaf spring hangers, build a custom front leaf spring hanger bracket off the front bumper, use TJ Wrangler rear lift coils, build custom adjustable rear suspension linkage in the same configuration as stock, gear to 4:56 with ARB's, and slap on some 35" somethin's with aluminum 15x8" rims with about 3.25" backspacing. If budget permitted, I would cut the rear wheel well comp style straight back to the taillight, relocate the gas tank up into the rear cargo (or use a fuel cell $$$$) with a custom enclosure and when making the new rear control arms, make them long enough to stretch the rear axle back about 7".

That would be sick.