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  #1  
Old 11-12-2010, 07:48 AM
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rustywagoneers_com rustywagoneers_com is offline
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Lower SOA Option

With any significant amount of lift in a V8 powered FSJ, you can get into bad operating angles on the front driveshaft very quickly. While an SOA is a (relatively) simple way to gain clearance for a lot of tire - it is almost a guarantee of front driveshaft issues.

However - most of the front axles that you will find from non-FSJ applications are set up for SOA. So what do you do then? Well, it is entirely possible to do a little grinding and weld perches on the bottom of your GM, Dodge, or Ford axle - but then you still have the 'hooks' underneath your truck's front axle ('hooks' in this case refers to stuff that will hang you up on obstacles, like your u-bolts and such).

In an effort to maintain decent front driveline angles, lower center of gravity, and make use of the least expensive donor axle sets, I have been trying for a long time to come up with a solution to combat the height of most SOA setups. I have come up with a pretty good answer, which I will share here.

Dodge truck front leaf springs.

Here's the thing; Dodge front leaf packs have the rearward eye wound UNDER the spring, instead of above it - this moves the main leaf 2 inches (roughly) closer to the frame than a stock (or most normal) leaf spring pack. Coupled with the fact that most Dodge front leaf packs are 3 fairly thick leaves actually makes them a thinner pack thickness than the 7-leaf FSJ front packs. The thinner pack reduces the height from the SOA slightly. Also, the Dodges sit flat or slightly negatively arched under load, again bring the axle CL closer to the frame - limiting the amount of lift.
It is also nice that the Dodges are a thick main leaf which should be less prone to bending than the stock FSJ main leaves.

The downside is pretty minor - the eye-to-eye length is 48" instead of 47".

If you want to keep your shackle in the stock location and do the Dodge spring swap with the least amount of work, move the rear hanger of the front spring back on the frame 1". In order to do that, get some 3/16" by 1" steel. Cut 3 pieces 2" long. Use one piece of 3/16"x1" as a 'spacer', and the other 2 as 'stops'.

Hold or clamp the spacer behind one spring hanger tight against it and square with the frame rail. Place the first stop behind the spacer, tight against it and the frame, and weld the stop in place. Break the spacer free and repeat the procedure on the other side. Now you have a solid location for the spring hangers that will be exactly equal when the work is done.

Cut the heads off the rivets with your favorite implements of destruction - but DO NOT mangle the hanger. Also, remember to cut the weld on the inboard side of the hanger where it meets the frame rail. (remember; you are reading all of this on an internet forum - so use any of this information at your own risk, don’t just hack into your truck's suspension because of what some crackpot el-cheapo said on the internet)

Once you get the hangers off the frame, grind everything nice and flat on the frame and the hanger so they will go together nicely when you put them back on the frame. You are a grown up now, so no booger welding over slag or faking it or welding through rust flakes. Take a little time and prep the area well.

Installation is reverse of removal. However - the Dodges use 1/2" bolts instead of 9/16" - so make some 1/8" or 3/16" thick plates to use as washers which you can tack to the mounts and shackles. It probably wouldn't be a problem with just washers - but better safe than sorry.

The first truck that I have done this on has turned out really well - I will try to add some pictures soon. Next time, I will likely move everything FORWARD a little and do a shackle reverse, with the shackle bushing through the frame, and use a fixed front mount. Or, move everything forward by putting the shackle ahead of the front crossmember.
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  #2  
Old 11-12-2010, 04:55 PM
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sounds neat. so what's a rough guess at what it will it net you in height and how is the flex of those springs? where's the pin sit on those springs? i like the stretch and shackle reverse idea.

I'd like to keep my height at 6" of lift and do a little cutting and get some bigger meats under it and make her a little more flexy. this sounds like a good way to go without breaking the bank.
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Old 11-12-2010, 05:05 PM
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Rough guess right now is that this thing has 4 inches of lift.

I will get solid answers and pictures over the weekend.
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  #4  
Old 11-12-2010, 05:06 PM
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Quote:
Originally Posted by CutterN55
sounds neat. so what's a rough guess at what it will it net you in height and how is the flex of those springs? where's the pin sit on those springs? i like the stretch and shackle reverse idea.

I'd like to keep my height at 6" of lift and do a little cutting and get some bigger meats under it and make her a little more flexy. this sounds like a good way to go without breaking the bank.

A SOA will net you about 6"s of lift. Going this other route sounds like you will be closer to 4"s or so...
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Old 11-12-2010, 05:06 PM
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Ohhhh... Ya beat me to it...
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  #6  
Old 11-12-2010, 09:11 PM
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I like the sound of this setup. Really looking forward to seeing some pics. Are there any years of Dodge springs that people should look for? What about differeneces between models like between 1/2 tons and 1 tons?

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  #7  
Old 11-13-2010, 09:51 AM
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this caught my attention as well... So, what of the front driveline? Steering? Someone has to post it, so might as well be me....
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  #8  
Old 11-13-2010, 10:01 AM
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Steering and driveline shouldnt need to be changed with only 4"s of lift. I always reccomend a DPA with 4"s anyway though.
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  #9  
Old 11-13-2010, 10:05 AM
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Well, let me back up for a minute there...

Steering wont need changed due to the severe angles like what is encountered with a normal SOA.

So, if you SOA your current axle, you will be fine.

However, if you want to swap to a dodge or chevy axle for either strength or better gearing, you will have to address the fact that most have a different seteering set-up to begin with.
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Old 11-15-2010, 09:37 AM
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Currently the truck is sitting slightly nose-down. Once I get the rear height reduced somewhat and level the truck out - I expect the front will gain a little more height due to some weight being transferred off the front.

Currently, with old-school 'low' high-steer arms on the GM D44, the drag link actually runs just the slightest bit UPHILL from the pitman arm to the tie-rod. If it isn't at least dead-level when the rear height is corrected, I may switch this to a DPA and remove the high-steer.



The beater DD 82 with some moderately saggy springs that I drove to the shop on Sunday measures 11-1/4" from the top of the frame rail in front of the shock mount to the centerline of the front axle tube.



This is the condition of the 82 saggy springs in the above example:



The truck with the Dodge front springs measures 14-1/2" from the top of the frame in the same location to the centerline of the axle tube. Which, in case you hadn't figured out by now - is just over 3 inches of lift up front. However as mentioned, I expect it so gain some height as the rear comes down.



Here is a shot of the stop mentioned in the first post. It really is very simple - use a spacer to locate the stop, use the stop to locate the spring perch.



The front driveshaft is no longer pulled out of the splines. It is close to maxed out, and will need to be extended in order to restore proper travel - but at least it isn't on the verge of coming apart at all times.

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Old 11-15-2010, 08:13 PM
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wouldn't it be easier to flip the main spring on the stock pack? i have a hard time believing it would cause any stress/damage to the main, bending the 'other' way.

Al
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  #12  
Old 11-15-2010, 08:22 PM
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Quote:
Originally Posted by AlsChopShop
wouldn't it be easier to flip the main spring on the stock pack? i have a hard time believing it would cause any stress/damage to the main, bending the 'other' way.

Al

Ive been thinking the same thing and I might just try it with a J10 that Im getting soon.
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  #13  
Old 11-16-2010, 07:00 AM
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Quote:
Originally Posted by AlsChopShop
wouldn't it be easier to flip the main spring on the stock pack? i have a hard time believing it would cause any stress/damage to the main, bending the 'other' way.

Al

The amount of free arch in the stock springs makes it almost impossible. That was the path I wanted to go with this cherokee initially. Plus you can ditch that ultra-huge and ultra-squishy bushing at the frame side of the spring by doing this. About the only thing you can do with the FSJ main leaves is to turn the eyes around - which I had a hard time finding a spring shop who would do it.
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  #14  
Old 11-16-2010, 06:55 PM
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I just converted from SUA to SOA using stock 1/2 ton Chevy leaves. Granted, this was on my Nissan, but it had 4" wag lift springs and when all was said and done I am only about an inch taller. The chevy leaves bolted right in without moving anything.
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