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Soa Front Leaf Conversion, 8"+ Lift


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I just picked up an 89 Comanche with 100,003 original miles, great condition. I'll have pictures up on Sunday.

 

I used to have a lifted Mitsubishi Mighty Max, and contemplated doing a straight axle swap for a long time. This will be my third Jeep, and I have always wanted a Comanche since I was 16. All my friends drive big Toyotas, and I don't do any intense rock crawling, so I am building this to my liking: tall, light trails, mostly mudding.

 

Here are the parts I have ordered, this build will take place next week. Hopefully be done by next weekend.

 

Ford 8.8 rear, keeping Dana 30 front (for now) - 4.88 gears

Front YJ Leaf springs, 4" lift - Rusty's offroad

Rear MJ Leaf springs, 4" lift - Rusty's offroad

1.75" lift YJ shackles, to go in the rear of the front leaf springs

3.5" Drop pitman arm

AA SYE

TC drop

RX35 shocks - Rusty's

 

If a SOA gets 4-5 inches, once the leaf springs settle I anticipate 8" inches or so. For now I will run 35's.

I think this setup will future proof me for when I am ready to trim, put a Dana 44 up front, and get bigger tires.

 

The part I am sincerely concerned about is STEERING! Any one who has experience with big SOA YJ's, or can offer any advice please do.

I just want to get the drag link to not hit the leaf springs. I know TERA and RRO make high steer kits for over $500, but I think they are for coils.

 

This LOOKS like it might work: http://jb4x4.com/store/jbrsb.htm

Seen in use: https://plus.google.com/photos/106141265775993604532/albums/5459311166661517569?banner=pwa

 

Just not sure with my amount if lift if the drag link will clear the leaf springs. Thanks for looking.

 

 

 

 

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  • 4 weeks later...

Sorry for the really long delay. Had a couple issues and took time to get the parts, but here it is sitting now. Decided to keep the Ford 8.8 rear, and unfortunately that leaves my options limited in the front, but I will regear 4.88, (35's for now), and probably upgrade the front axle.

 

The problem is that we want to do a front shackle reversal. As you can see, the angle would be ridiculous. The front mounting location is soo much higher than the frame. My shackles are also not very long, because I tried to get the height to match the rear. Is putting the shackles up front, and probably building a cross member to lower them even more, the only way?

 

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Super Scary!  Why do you want so much lift?  If it's purely a trail rig and not to be driven on the road I can totally understand.  But if you plan on driving it 50mph be prepared for death wobble with that much lift.

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Two questions:

Why did you decide to convert the front to leaf springs?

Why do you need 10" of lift?

 

As far as steering goes, build and finish the front suspension first, then figure out the steering. Unless you're okay with horrible bump steer, the drag link needs to be as close as flat as possible. With this much lift that will mean high steer, at least for the drag link.

 

Another option, which would automatically prevent death wobble in the process, would be hydraulic steering. 

 

 

Spring over axle will net you: the thickness of the spring pack plus the diameter of the axle tube plus the spring perch. That usually adds up to about 5.5". With the natural rake out trucks have most people lift the front 6.5" to level it out. With 4" lift springs the 5.5" becomes 9.5". Add in the original old sagged springs and you should be more than 10" from where you started.

 

SOA rear and 6.5" up front is perfect for 33" tires. Larger than 33" tires you would need to build the front axle to the extend that you might as well throw a Dana 60 under there. I retained the D30 for not quite 3 years after I went to 35" tires. In that time I went through 4 axle housings and over 20, possibly 30 axle shafts, u joints and unit bearings. And that's with the stronger Spicer 5-760x u joints. Also tried Duralast Gold (junk compared to Spicer), Neapco Bruteforce (also junk compared to Spicer) and a Alloy USA Chromoly joint (twice the cost of the Spicer, still broke on the 4th trip out).

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To comment on some more issues from the original thread that started this build thread, going that high IHIGHLY advise going to full width axles. Yes, your tires will stick out, which might be an issue in some states, but at least you will be able to turn without flopping over onto your side.

 

Waggy axles have been suggested. A Waggy D44 is about the same width as a stock Comanche or Wrangler axle.

You mentioned a Wrangler D44. If you meant for the front, it still has Dana 30 outers, and the low pinion pumpkin which is not much stronger than a high pinion D30.

 

Pretty much all Dana 44 front axles us the same u joints as the larger shaft stock Dana 30 uses. Unless you pay $240 each for CTM ones, they will break.

 

If you want to run 37" tires, a front D60 is pretty much a must.

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OK well I admit I underestimated this amount of lift. I still think 35's will look somewhat normal without any trimming though.

 

I will pretty much be doing high steer, with the raised bracket and 3" drop pitman arm, the drag link should be pretty level.

 

Right now my question is about mounting the front leaves and shackles...

 

I probably need to get the longest shackles possible, and put them in the front. Is this the only way? Will I almost definitely have bump steer? Why would death wobble be an issue?

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Front leaf with shackles in the front is simple, why people go this route as I did. Rear mount for leaf use factory lca mount then use about a standred 5" shackle in the front and adjust from there. If want to go shackles in rear you would want to french them into the frame to get your desired result. But keeping in mind that must provide room for the shackle to swaing back as the leafs flatten out. This approuch involves more fab work, clearly. And also with 10" lift Id suggest a trac bar and brace as steering willbe grappy with no hgydro assigt at least.

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Front leaf with shackles in the front is simple, why people go this route as I did. Rear mount for leaf use factory lca mount then use about a standred 5" shackle in the front and adjust from there. If want to go shackles in rear you would want to french them into the frame to get your desired result. But keeping in mind that must provide room for the shackle to swaing back as the leafs flatten out. This approuch involves more fab work, clearly. And also with 10" lift Id suggest a trac bar and brace as steering willbe grappy with no hgydro assigt at least.

 

Thanks MiNi Beast, and sweet rig. How is the front leaves holding up for you?

 

Frenching the shackles into the frame... what frame? Is the unibody strong enough? We were going to reinforce it then weld the mounts onto the reinforcement. I just don't see anyway to make up the huge difference in the front, without having an extreme angle.

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Sorry, thought we was passed technical terms in means of Frame, yes we all know as MJ or Xj owners know we have a unibody frame, so let's not make something more complicated. I was referring to the front being that was where the question was directed, yes naturally you are going to want to reinforce any mounting area to help in aide to stresses to the rig itself.

 

Do some reading and go from there.....

http://www.pirate4x4.com/forum/jeep-cherokee/720309-totm-unibody-front-leaf-spring-conversions.html

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  • 1 month later...

Sorry it's been so long, lots of waiting on parts and a few complications. I believe the mounting to the frame, reinforcement, the front cross member and shackle reversal, etc, all came out really well. The problem right now is do you think this drag link angle is too much or doable? I see a lot of other build threads where it ends up close to that. My only other option would be to hold off for full width, (ditch the ford 8.8 rear), and do a true high steer with flat top knuckles and the tallest high steer arm I can find. I'm not sure it will end up that much higher though, because I'm already using that bracket I linked earlier.

 

c85889e7fe1dec4d38a8b908d988f119.jpg

 

116c243a99116f54c7ea9d66fc9b000e.jpg

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Could also use a 6" drop pitman arm, just a thought. But yeah man looks awesome for a bdmt. Not sure if you plan to hit trails or boggs but either way I see full widths in your future. Also they sell hy steer knuckles for a d30. But ummmm yeah.

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I actually decided to wait on full width axles. Finally found a deal on a pair coming right out of a 79 F250. I'm driving 2 hours tomorrow to hopefully buy them.

 

Lol BDMT... I mostly do trails and mud. No crazy rock crawling, but trails are great and muddy up here in Oregon. I don't think it's too ridiculous.

 

Was gonna do 4.88's, but now I'm getting the axle's with 4.10, I'll probably run it for a while on the 35's, and we'll go from there.

 

64440_381135142012452_1157082659_n.jpg

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Where abouts in Oregon are you?

 

I live in Southern Oregon, Medford area. 

 

Jeeper, haha that CJ is not mine, but yeah that thing is a beast.

 

Now I just need to find a machined flat top knuckle, high steer arm, and drag link... budget is tight. Let me know if you have suggestions for good price.

 

1170669_356492994481220_901575539_n.jpg

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  • 1 month later...

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