build thread from the wind tunnel

[Gunnibronco]

Thanks. Not sure I'm ready to buy a set of custom springs, but its tempting. Moving my springs back will involve removing my rear bumper & rebuilding the mounts. The guy who made my bumper did a jack-ass job of mounting it, welded it to my frame (really, it wasn't me). It's going to be a bitch to remove it. But it sounds worth it.

[Justin]

I bet you could find some light pickup Springs that you could run without needing custom.

[Gunnibronco]

We are on the same page. I've been Googling & searching CB.com hoping to find an answer, but I haven't found anything that fits the bill simply. I think the magic combo of leaf length, width, axle location, & spring rate might not be hacked yet.

[Gunnibronco]

This is as close as I've come, but he hasn't actually tried it.

http://classicbroncos.com/forums/showth ... p?t=251078

I don't know enough about our stock Bronco shackle positioning vs flipping it, etc. I don't want to completely screw up my truck. I think I'll put off resetting the rear end for a while so I can think this through. I have lots of other stuff I can do, while I read up a little.

[Justin]

I kicked it around for a bit then decided just to link it. If you can hack the engineering, the level of work isn't that different. Mostly.

[Gunnibronco]

http://littlekeylime.com/MrN/mrnimages/leaf_springs.png

What is the advantage/disadvantage to the shackle facing up vs down?

Is giving up an 11 leaf WH leaf pack and switching to a stock Tahoe spring with 4/1 leaves a good move? I assume this is 4 full leaves + 1 zero rate leaf?

Too bad the Explorer spring rate is so low, I have a set of those.

[Justin]

Explorer with an additional leaf?

[Gunnibronco]

Used leaf springs are cheap, and both Tahoe & Explorer packs are available fairly close to me. Its sort of scary to start experimenting with this.

[Gunnibronco]

I've decided to try a set of Tahoe springs. I've done some reading, and the longer spring, with less built in arch should add some flex (I hope). I should be able to set the Tahoe spring even with the back of the frame, and get about 4 inches added wheel base. Most longer springs have too much "back half" of the spring. To get 4" more wheel base, you'd have to extend the frame, but the Tahoe dimensions, seem just about right. I might notch the crossmember and move the fuel tank back if I can grab another inch or two extra. I'm not sure how my wheel openings & flares will line up at that point. The real trick will be to get the right lift from the springs. I'll flip the shackle hanger, allowing me some adjustment from the length of shackle. I'll also try to tuck the front of the spring higher than the low hanging stock spring hanger. Since the Tahoe spring bushings are 3", I'll be using some Ruffstuff spring & shackle hangers, and building some outriggers- something like this:

http://offroaddesign.com/catalog/suburb ... ackets.htm

I figure, if I don't like the springs, I can always have a custom set made. If this works out, it might keep me from linking it later.

Finally got to use my awesome Chrismas present. They are about 28" tall collapsed & up to 46" tall extended.

P1030194.JPG

It took plasma, a grinder, a sawz all, crow bar & floor jack to get the bumper off.

Grind, grind, grind, grind.

Fresh start

P1030195.JPG

P1030196.JPG

P1030197.JPG

Ran out of grinder disks, but got everything chopped off the driver side, still needs cleaned up.

[Kinder]

I love it when you jump head in on a project and commit, I'll be following along and taking notes. Good luck!

[Jesus_man]

Yeah I am excited to see how this all works for you. Interested if the tahoe springs offer good flex. I'm pleased with my 11 leaf pack, but I don't like how low the spring hangers are.

[Gunnibronco]

I love it when you jump head in on a project and commit, I'll be following along and taking notes. Good luck!

I could sit and scratch my head for a week about this, and not make any ground. I figure my axle is moving back one way or another. Worst case scenario, I'll do what Cory said & just reinstall my stock springs set back 4".

Interested if the tahoe springs offer good flex.

That is the million dollar question.

[Colorado75bronc]

If you go 4", tape a plumb-Bob to the front of that crossmember and ensure that you have enough clearance on up travel. My d60 only allowed 3 1/2" due to the size of the diff cover, the 9" is smaller, but by how much I am unsure.

Sent from my SAMSUNG-SM-G890A using Tapatalk

[Gunnibronco]

Drove to Saguache and picked up a set of Tahoe springs. Saguache makes Gunnison look like a metropolis, and he lived 15 miles east of town. Scrap hauler, buying & parting cars on the side. The springs are in pretty good shape, excepting the grinder knick he put in one. Ruffstuff stuff should be here tomorrow. I think I've figured an easy outrigger. We'll see.

P1030203.JPG

Had to cut more floor out to install the Atlas shifters. I think I'll be cutting some length off these and pulling the shifters back a little further. Still need to install the doubler shifter, ZF shifter, and driver seat first.

I had read Advance Adapter's instructions suck. Today I can confirm that. Not even a real diagram of how all the parts fit the shifters. I will be removing the t-case again, to install the bracket for the doubler shifter. It's also obvious they make updates to their products, without updating the instructions.

P1030201.JPG

Also spent some time finishing frame clean up, and getting the spring perches ready for a 2.5" wide spring. When I bought mine from Ruffstuff, they didn't have a 2.25" perch, so I welded 1/8" flat along the sides of a 2.5" perch, creating a small cradle to set the springs into. I cut those off today, returning the perch width to 2.5".

[Jesus_man]

You might want to brace the end of that shift rail for the atlas off the tranny or something. Of course, that could depend on how much you shorten it.

Great progress once again!

[Gunnibronco]

You might want to brace the end of that shift rail for the atlas off the tranny or something. Of course, that could depend on how much you shorten it.

Great progress once again!

Thank you.

I agree. There are 2 threaded holes (for the old t-case shifter?) in the transmission, very near the end of the tube/shifters, that would be easy to fab up a bracket to brace the end of the tube/linkage.

[Jesus_man]

That's exactly what I did. You don't want your twins flopping around when you're trying to work 'em....

[Gunnibronco]

That's what she said.

[Gunnibronco]

4" back, 9.25" from frame to axle.

P1030269.JPG

Doh!

P1030267.JPG

The frame crossmember is 6" directly above the center section.

Realistically, how much up travel will a leaf sprung truck get?

[Digger]

5" is sufficient.

6" is better. You can always limit uptravel with bump stops.

[Justin]

What digger said. I'm setting mine up for 6.75 to account for a future set of links.

[Gunnibronco]

Thanks,

That pic might be more like 4.5"-4.75" back. Can someone measure their stock or other known axle location to the rear most end of the frame? I measured 31.5" before starting this, my 66 measured 32.25". Just curious.

My questions:

Does the axle move back when the spring compresses? I would think it would. How far? Basically, how much horizontal space should I leave between my diff & my gas tank? I cut the body panel pinchweld, folded & welded it to the bottom of my floor, so I can move my tank back another 3.5". Pics with the axle at 4"+ back, gas tank pushed back even with the frame. I'd like it as far forward as possible.

P1030270.JPG

P1030271.JPG

How long a shackle should I shoot for? I was thinking 4"-5".

Can I remove the zero rate spring at the base of the pack?

I built some outriggers & used some Ruffstuff spring & shackle hangers. If I mount both at the bottom of the frame, it really looks like I'm going to have about 6" lift. Just guessing. But Im thinking, I'm going to go ahead & tack everything together that way to get a baseline, then start adjusting front & rear mounting points.

P1030273.JPG

P1030259.JPG

P1030261.JPG

[Jesus_man]

That is a good look!! I can do what you're doing, but where you'll be miles ahead of me is moving the fender opening. I have no body work experience!

yes, The axle will travel towards the shackle slightly when compressing.
The more the leaves are arched, the more it travels until your shackle can't go anymore. Might be worth a call to deaver or something to see if they can offer any insight.

When you had that tank made, were they open to other customization ideas? Like would it be beneficial to have welded in a concave section vertically into the center of the tank at the front to clear the pumpkin? Like cutting a 12" pipe along it's axis and using 120* of it?

[Gunnibronco]

Thanks for confirming that. I might disassemble the leaf pack and only use the main spring to see what kind of compression & droop I get. Then set my bump stops & gas tank, and adjust my wheelhouse & quarter. I don't want to get into any paint or real bodywork. There is 1/4" of bondo falling out where the quarter meets the rocker, on both sides. I might do a quick patch on the front of the opening after the flare is moved, then maybe just bedline the tub from the body line down. We can get a blue bed liner that looked close, or custom tint it.

Aero made my a couple inches shorter, but sounded like they would work to get what you wanted.

[Gunnibronco]

If anyone wants to lift the back of their Bronco 7"+, I know how.

P1030276.JPG

P1030278.JPG

Forgot the SD card & the camera ran out of memory.

The axle ended up right about where I wanted it horizontally, but I need to pull about 4" out vertically. Unfortunately, this means a complete redesign of my spring hangers, and maybe my 4 rear body mounts. I have an idea for the spring hangers, and will probably incorporate body mounts into the spring hangers. Thankfully, I have a bunch of 2x4x.25 I bought, but never got around to building rock sliders.

[Colorado75bronc]

I would also flip the rear shackle back like stock, it will net you roughly half of the distance the rear spring eye moves up

Sent from my SAMSUNG-SM-G890A using Tapatalk

[Gunnibronco]

I would also flip the rear shackle back like stock, it will net you roughly half of the distance the rear spring eye moves up

Sent from my SAMSUNG-SM-G890A using Tapatalk

I thought of that, but was able to make new mounts that keeps the shackle flipped. The rear mount of the spring is so close to the bumper, with the shackle in the stock position, it would rotate through the space occupied by the top 1/2 of the bumper. In the stock position, unless the shackle hanger is mounted below the frame, the shackle would only be a few inches long, or it would put the spring into the bottom of the tub. As it its, I'm going to have to do something with the bottom of the bumper (notch it for the shackle, or remove it outboard of the frame). Actually, because I'm going to have to remove most of the receiver hitch, I might just end up building a new bumper.

Yesterday, I cut everything off and made most of all 4 new mounts. I got the passenger rear mount tacked on. Hopefully tonight I'll get more together and take some pics.

[mickphatmac]

Lookin' GOOOOOD!
Great progress, keep on it!

[Gunnibronco]

Getting closer.

Rebuilt the spring hangers out of 3/16 2x4 & plate.

Both sides are sitting at 10.5" from frame to axle. So I figure just about right, with a little more weight. But the axle is a little forward of where I'd like it, and the shackles need rotated back a little. So I cut the front hangers off, and will move them back about 3/4" and check again.

[Gunnibronco]

Today, I cut the front spring hangers off. I finish welded both brackets, prepped and placed them back on the frame 3/4" further back. When I reassembled it all, everything settled in, just about right. With it sitting back on its tires, the axle is 3-3/4" further back than when I started. Shackle angle looks good. Pinion angle looks decent to the eye, and I can adjust the t-case up or down a little to help, before finalizing the crossmember. The frame to axle measures at 10". I'm shooting for a number around 9.5" when fully weighted. If its sitting low, I can always add a 1" lift block, or get a longer shackle (5" shackles right now). And since I have the adjustable front coil buckets, I can pretty much dial in my lift as needed. So I think I'm close enough to finish weld all the brackets & hangers, and finish plating the frame around the pick up points.

P1030307.JPG

P1030296.JPG

P1030299.JPG

P1030300.JPG

P1030303.JPG

P1030301.JPG