1981-ton Bronco (99-04) leaf spring SAS

[1981tonbronco]

Here is a little info on my truck as it sat before the swap:

• 1981 custom package w/ rear sliding windows, GT rollbar, front bench seat and factory tachometer
• T19 transmission swap. 5:1 first with synchro'd 1st and 2nd (unlike 'granny' T18 and NP435)
• Mildly build 4.9 300 straight six (Holley 390 4bbl, offenhauser dual port intake, efi exhaust manifolds, 1.6 chevy rocker arms, port and polished)
• Stock New Process 208 transfer case
• 4" lift with extended radius arms and full rear leaf pack
• 35x12.50x15 BFG km3
• Custom rear bumper
• Rock sliders from 2x6 .250 wall rectangular steel
• Old Smittybilt cherokee bumper modified
• Desolate Motorsports rear gas tank skid
• Custom Saginaw power steering pump bracket

I have wheeled and driven this truck across the country for 10 years without a single problem or complaint. It has driven amazing on the highway and handled anything I have thrown at it on the trail. I have gotten into significantly harder wheeling the last few years and sadly, I did not trust the TTB/steering to hold up to lockers and 37"+ tires. I have no desire to attempt it and break major parts on the trail in the middle of nowhere. I grew up wheelin' in my dads old rigs and I have always wanted a 'traditional' rockcrawler. Leaf springs, big tires, lockers, low lift, etc. They are simple. There are pros and cons to every build but I wanted to do something a bit different than most one ton swapped rigs these days with links and coilovers so I settled for some basic leafsprings. I know that there wont be as much travel but the bigger the tire, the smaller the rock/hole so getting these axles under the truck will allow me to run the 38x12.50x17 that I am shooting for. Those tires combined with a few inches of useable travel and lockers should be able to get me anywhere that I want to go.

Here are some pics of the rig before the swap and some forklift pics for those that claim that the TTB does not flex:

 

[1981tonbronco]

Here is a parts list of what I used for the build:

• 99-04 Superduty dana 60 w/ 4.30 gears
• 99-04 Sterling 10.50 w/ 4.30 gears and Ford OEM e-locker
• Stock rear bronco springs up front (RUF)
• Ruffstuff spring hangers
• Ruffstuff lower track bar mount
• Ruffstuff 7/8" heim (axle side track bar joint)
• Ruffstuff diff covers front and rear
• Ruffstuff lower shock mounts front and rear
• Ruffstuff rear U-bolt plates
• Sky Offroad lo profile shackle hangers and 2" shackles
• Sky Offroad U-bolt flip kit
• Desolate Motorsports rear upper shock mount
• Broncoair track bar mount, track bar and EMF frame side joint
• Ford OEM F250 shock towers
• Stock 99-04 steering
• Stock bronco pitman arm
• 10" stroke Bilstein 5100's for the rear
• old 8" stroke shocks from the rear in front (for now)
• 37x12.50x17's (for now)
• 17x9 Vision Wheel steel wheels

 

[CDA 455 II]

Welcome; fellow FSBronco.



I'll be following along to steal ideas/tips/tricks, etc.

 

[CDA 455 II]

Crazy question:
Do you think a trac bar is necessary for a front leaf spring axle?

 

[1981tonbronco]

Crazy question:
Do you think a trac bar is necessary for a front leaf spring axle?

So I have actually had a few people ask me this question so it is not crazy at all!

From what I have heard, running the stock rear springs up front is really flexy but can feel a little bit unstable on the highway. On a full-size rig with really soft leaf springs, the leverage of the big tires and weight of the vehicle will want to push the axle laterally. Especially on the rocks. It’s just some reassurance to keep everything cycling correctly. Also, if I ever break a leaf spring then it will keep the axle in place at least to limp off the trail.

99-04 super duties and excursions on leaf springs use track bars and since Ford figured they needed one, I didn’t think it would be a bad idea to have one as well. Most leaf spring swapped rigs are strictly rockcrawlers and this truck sees a lot of road miles to get to the trail.

 

[1981tonbronco]

First task was to build the front crossmember to brace the front of the frame, as well as give the spring hangers a place to sit. It is 6x2 rectangular steel that was .250 wall. The frame horns were previously boxed with .250 wall for the bumper mounts. The front of the crossmember sits just flush the the lower edge of the frame. The crossmember is also designed to be the winch tray. The back bolts are drilled and sleeved so it is water tight. The front bolts are through the .250 fairlead plate with two DOM sleeves underneath/against the crossmember for strength and bolt protection.

 

[1981tonbronco]

Onto the tear down process! I will have to admit that it is a very nervous feeling, having your truck hovering on jack stands. Theres no turning back now.

I would never give the typical middle finger salute to the beams because they have been an amazing suspension set up. Everything from cruising the dunes to the red rock at Moab, they have performed incredible. Never had a problem with alignment or excessive wear on steering/suspension parts.

Removed the coil towers and cleaned the frame up.

9" was removed. The overload spring is coming out of the current 4" lift leafpack and an Offroad Design zero rate will be bolted in. This will allow me to push the axle back either 1" or 1.5" depending on the position you place it. I went with the 1.5" option and the 37/38 will sit perfect in the wheel well and will not contact the front lip of the rear fender. It used to rub there before even with the 35's. I used a 2" block to mock up ride height before I order the Deaver J40 springs which are 5" of lift. This will net me 6" of lift with the ORD zero rate. Pinion angle was set and everything was burned in by TRA Motorsports in Camarillo, CA.

 

[CDA 455 II]

So I have actually had a few people ask me this question so it is not crazy at all!

From what I have heard, running the stock rear springs up front is really flexy but can feel a little bit unstable on the highway. On a full-size rig with really soft leaf springs, the leverage of the big tires and weight of the vehicle will want to push the axle laterally. Especially on the rocks. It’s just some reassurance to keep everything cycling correctly. Also, if I ever break a leaf spring then it will keep the axle in place at least to limp off the trail.

99-04 super duties and excursions on leaf springs use track bars and since Ford figured they needed one, I didn’t think it would be a bad idea to have one as well. Most leaf spring swapped rigs are strictly rockcrawlers and this truck sees a lot of road miles to get to the trail.

Good points.


I still have TTB;
For similar reasons; I'm swapping in 2013 F-350 front coils with 6" lift.


For my rear axle suspension I used my old '99.5 front leaf springs.

 

[1981tonbronco]

Good points.


I still have TTB;
For similar reasons; I'm swapping in 2013 F-350 front coils with 6" lift.


For my rear axle suspension I used my old '99.5 front leaf springs.

I am very excited to follow your build as well! Sounds super cool.

 

[1981tonbronco]

Next was setting everything up and seeing where it wanted to sit. Typically people trim the front crossmember to fit a track bar but I did not want to do that. I opted for the Broncoair track bar and bracket, which puts it right above the housing. These parts were designed to work with their Balljoint 60 coilover/ coil spring SAS so some modification was necessary. The track bar needed to be shortened so that it could sit just inside of the spring perches and the lower mount was set so that the both the track bar and drag link were at parallel angles. I am aware that the overall length will be shorter than the draglink and that could cause bumpsteer but with the leaf springs doing majority of the job of locating the axle, it should not be that big of a deal. Only time will tell.

The Ruffstuff spring hangers were flipped backwards, placed all the way forward on the new front crossmember and tacked on. I wanted to push the axle as far forward as possible to increase the wheelbase a little and prevent the tire from stuffing into the back of the front fender during bump. The u bolts were snugged, the Sky shackle hangers were clamped on to see where the shackle angle was at ride height and then it was tacked it on. Lower shock mounts were placed on the outer edge of the u bolt plate and centered between the u bolts. You are able to get the shock off without removing the u bolts, which is nice. The shock tower was tacked on as far up as possible and placed where the shock wanted to sit once bolted onto the lower mount.

Here is a shot of the Sky Offroad lo profile hanger and shackle at height.

 

[1981tonbronco]

Everything starting to come together! Here are some shots of the front and rear before everything was burned in. You can see in the picture of the rear suspension, the rear upper shock mount from Desolate Motorsports. I will post some specific details on that later.

Put on fresh brakes and had a custom hardline for the Sterling 10.50 made from TRA Motorsports in Camarillo, CA.

 

[1981tonbronco]

Everything is painted and assembled. Wrapped up the front brake lines with some brackets since the coil tower was removed. The rear is waiting for a driveshaft and then its time to get it on the forklift!

 

[no class]

Rear leaf up front is fine without a trac bar. I have a super cab long bed with a 460 and I used the heaviest rear springs for an F150 up front. With 39.5 Iroks I can run down the highway at 70mph with one hand on the wheel.
The downside is my front flexes so much I need a limit strap to keep my front driveline front separating. A friend used super duty leaf pack on his SAS (springs for a 5.4 truck) and they basically don't flex at all.

 

[1981tonbronco]

Rear leaf up front is fine without a trac bar. I have a super cab long bed with a 460 and I used the heaviest rear springs for an F150 up front. With 39.5 Iroks I can run down the highway at 70mph with one hand on the wheel.
The downside is my front flexes so much I need a limit strap to keep my front driveline front separating. A friend used super duty leaf pack on his SAS (springs for a 5.4 truck) and they basically don't flex at all.

That is good to know about the stock springs up front, thanks! I was thinking about it the other day and IF somehow I broke a leafspring, then I would still be able to limp home safely with the trac bar. I have heard of guys breaking 2wd stock rear springs (2.5" wide instead of 3") but never bronco springs. Since they flex so much with big tires, you never know.

That seems to be the common response from people with superduty and even excursion springs. I am assuming it is because those springs are made for one ton vehicles, which means stiffer springs would be required to support the increase in weight above the axles. Where as a one ton swap on a half ton truck would mean that half ton springs would be more appropriate. Especially for offroad use.

 

[1981tonbronco]

Just waiting on a driveshaft!

 

[fordpickupman]

It’s looking good! I love that body style.

 

[1981tonbronco]

It’s looking good! I love that body style.

thank you! For some reason you don’t see a lot of them used as serious wheelers (or in general) but they are the last generation of Ford trucks with glass headlights. Kinda cool

 

[Levigarrett76]

That is good to know about the stock springs up front, thanks! I was thinking about it the other day and IF somehow I broke a leafspring, then I would still be able to limp home safely with the trac bar. I have heard of guys breaking 2wd stock rear springs (2.5" wide instead of 3") but never bronco springs. Since they flex so much with big tires, you never know.

That seems to be the common response from people with superduty and even excursion springs. I am assuming it is because those springs are made for one ton vehicles, which means stiffer springs would be required to support the increase in weight above the axles. Where as a one ton swap on a half ton truck would mean that half ton springs would be more appropriate. Especially for offroad use.

Bronco is looking awesome!

In my 79 ford with dana 60 & 44 tsls and crossover steering and a a healthy 460 I tried out stock 3" wide rear leaves up front, tried adding some leaves and it was just too soft, and the axle wrap was bad. Still drove great down the highway.

I stumbled on some used 4" skyjacker rear lift springs , with those up front it rode and drove great, you could feel the steering trying to move the axle a bit off road in some situations, I eventually put hydro assist in which really helped. TRuck flexed great and like these guys the main problem was front driveshaft. Eventually I found a used tom woods long spline front 1350 cv driveshaft a 1410 at the pinion and i no longer had to worry about the ujoint binding or shaft coming apart.

 

[Deleted Member]

Yes! I love this thing! How's that Inline 6? Pushes it around just fine? The 300 is one of my favorite bulletproof engines...

 

[Levigarrett76]

Yea what he said! ever have any issue with the holley off road?

 

[1981tonbronco]

Bronco is looking awesome!

In my 79 ford with dana 60 & 44 tsls and crossover steering and a a healthy 460 I tried out stock 3" wide rear leaves up front, tried adding some leaves and it was just too soft, and the axle wrap was bad. Still drove great down the highway.

I stumbled on some used 4" skyjacker rear lift springs , with those up front it rode and drove great, you could feel the steering trying to move the axle a bit off road in some situations, I eventually put hydro assist in which really helped. TRuck flexed great and like these guys the main problem was front driveshaft. Eventually I found a used tom woods long spline front 1350 cv driveshaft a 1410 at the pinion and i no longer had to worry about the ujoint binding or shaft coming apart.

thank you! That’s funny you say that about using those skyjacker lift springs, I was looking at my current rear 4 inch lift springs and how they’d be perfect if the current stock rear springs were too soft.

I’m dealing with a pinion angle issue and gear break in so I have only put 80 easy miles on it. Zero bump steer but with the soft springs, I bet the track bar is helping out big time. Success!

 

[1981tonbronco]

Yes! I love this thing! How's that Inline 6? Pushes it around just fine? The 300 is one of my favorite bulletproof engines...

Yea what he said! ever have any issue with the holley off road?

This 300 is an incredible motor. Especially with the work done to it to open it up. It’ll do 16 hour trips with no overdrive from CA to CO in summer and not be a single degree over 195° the entire trip.

It was definitely being bogged down a little with the 35’s and 3.50’s but I could still even break tires free on the street. It’s badass. With the 4.30’s, in low range combined with the low end power of the 300, it’s going to be an insane crawler.

And luckily enough I have never had a single problem with the Holley 390. It’s been great. I’ve wheeled this truck for almost 10 years and have never been on an incline or decline where it would cut out. It is almost 15 years old now so I definitely have my eye on that new offroad style Holley when these throttle shafts get worn

 

[1981tonbronco]

Stretching her legs a little bit! Just testing out how everything fits/cycles.

 

[Levigarrett76]

Sex on wheels

Iirc the 4” springs netted around 6” lift in front

 

[WaterH]

Nice build.

 

[rattle_snake]

Cool rig, I like that generation of bronco. Well, I wish I had one of every generation.

 

[1981tonbronco]

Sex on wheels

Iirc the 4” springs netted around 6” lift in front

This build truly has exceeded my expectations in every way. Could not be more stoked on how it turned out. Time to get a front driveshaft and hit the rocks!

Nice build.

Thank you! Amazing that all the parts were from different manufacturers and everything worked out.

Cool rig, I like that generation of bronco. Well, I wish I had one of every generation.

Right? Haha there’s things I love about each generation.

 

[1981tonbronco]

Here’s some perspective on the rig. That’s a powerwagon with Thuren Fab suspension and 3” Kings. Both on 37’s.

Id say that’s a fullsize bronco now!

 

[1981tonbronco]

And just for reference, the final wheelbase is 108 inches. Exactly 3 inches longer than stock. 1.5 inches in the rear thanks to the ORD zero rate and 1.5 inches in the front based off where I mounted the front of the leaf springs.

Also, rear bronco/f150 springs have the center hole 1” forward of center. By the time the soft springs flatten out, this helps push the tires closer to the front of the truck (increased approach angle) and adds a little bit of caster. It steers incredible.

 

[WaterH]

Here’s some perspective on the rig. That’s a powerwagon with Thuren Fab suspension and 3” Kings. Both on 37’s.

Id say that’s a fullsize bronco now!

You'd think. I was in a autozone yesterday with my 90' Bronco on 38's and the guy who worked there was standing outside when I pulled up. Even asked me if I wanted to sell it. We get inside and he asks if it's a Bronco or a Bronco II.