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KB Article Leaf spring Update/Rebuild

2021 Arizona International Harvester Rendezvous
By Bill Hamilton (Bill usn-1)

As part of my SOA conversions I usually add an additional full length spring to the stock scout spring pack. This time I decided to take it one step further and do a little upgrade by adding anti-friction slides to each leaf tip.

List of materials used.

1 set of the top (long) leaves from stock spring packs.- A lot of guys part out scouts or upgrade to lift springs. If you are not in a hurry, you can normally get these for free or close to it. There aren't many Scouts in Europe so I was lucky and got Jeff at IH Only North to ship me a pair over.

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3 boxes of BDS-suspension 129007-1 sliders (10 per box)

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If you can't get the springs drilled for the above pads then look for something like this UHMW tape availible at some plastic suppliers like http://www.multicraftplastics.com/ or www.mcmaster.com

76475A66
Tape Made with Teflon® PTFE .032" Thick, 2" Wide X 5 Yard Length
In stock at $67.65 per Roll

or

76445A775
Strong & Slippery UHMW Polyethylene Tape 2" Wide X 5 Yards Long, .0325" Thick
In stock at $26.79 per Roll


2 packages of BDS spring(hendricks) clamps. BDS228007 (4 per package)
2 packages of Center bolts. BDS228002-1 (2 per package)

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Optional upgrades.

Heavy duty 3/8" spring plates and 5/8" U-Bolts
IH Only North

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Poly spring bushings

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So lets get started....

First is to remove the old spring pack.
Block the wheels and jack from the frame to allow the spring to droop.
Then spray a little WD-40 or penetrating fluid on the ubolts.

I leave the tire on the ground and only jack until all compression is relieved.
Then remove the nuts and ubolts.
Then unbolt the front and rear mount bolts.

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With the spring now out, I use a C clamp to hold it together while I remove the center pin bolt.

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You will also need to pry the tabs out on the clamps and remove them.

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Once seperated, you can see that the majority of spring wear(friction) occurs at the tips of each leaf.

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To replace the bushings it is recommended to use the cheap HarborFreight ball joint tool.
This makes a very hard, long job...very easy.
Using one of these can remove the bushings in the time it takes to turn the screw.
I prefer to use my impact wrench for this job.
These took about 30sec each.

If you have one that the rubber is deteriorated then simply use a 7/8" socket upside down on the tip of the screw where it meets the bushing.

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Then grab one of the donor top springs and your 4 1/2" angle grinder with a metal cutoff wheel on it, and remove just the eye from the spring.
This will leave a full length leaf to go just under the top leaf to help support the ends.
Under hard wheeling, the ends may start to curl. By adding this leaf, the ends are fully supported.

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But for now I will just assemble like the original.

Once the center bolt is in you can install the clamps.
Again I use a C clamp to hold in place while I bend the tabs over.
The clamps need to be located in the hole in the leaf to keep them from sliding off the end.

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I place mine on the bottom leaf to allow the maximum articulation. I used 2 per pack.

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Then reinstall with new hardware.

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Note how the second leaf now extends all the way to the eye on the top leaf.

After the install I jumped up and down on the back and noted a nice smooth and Quiet movement.
It was so much better that I now realize that my shocks are gone. The back end bounces free and easy.

I also did the before and after hieght measurements at the bottom of the rear bumper.
Before 22 1/2"
After 24 3/4"
So the 1 leaf and teflon sliders was good for a 2 1/4" lift.
I will need to wheel this some and see if it settles out any.
The replacement leaf had a little more arch left in it compared to my old spring.

I also rebuilt the front spring pack. This time I removed the second long leaf and replaced it with the second long leaf from the stock rear spring pack. The rear leafs are twice the thickness of my front leafs so i was concerned about being too stiff if I left both leafs in.

Again I adjusted the tip length to give full support to the top leaf.
When they were done and installed, the ride height had increased 1" in the front.
The spings move much smoother and quieter now. I will have to wait to see how they flex off road. Note I installed the band clamps towards the center to allow the packs to droop when off-road.

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Now we need to start preparing them to go back together.

After some scrubbing and some sanding, to include smoothing any wear lines down, I gave them a good coat of rustoleum black.

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The anti-friction pads I chose require locating holes in the springs.
Not sure if any of you have tried to drill springs before but they are not easy.

I sharpened up my small pilot drill bit and was able to use my drill press on low speed with lots of oil to go through them.
But I needed to increase the holes to 3/8" for the pads. My bits just weren't up to the task.
So I ended up having to use a 3/8" end mill with the speed as slow as possible and using oil. I was able to drill one complete leaf pack in about 45min. Each pad requires 2 holes!!

This was the only bad part of the whole job. Not everyone will be able to do this so plan ahead. I'm sure there are machine shops that would do it reasonably cheap.

Another option would be to glue the friction pads on.
Companies such as Graingers and McMasters sell a wide variety of anti friction stock material in all shapes and sizes. Some simple 2" wide X 1/8" sheet would work fine.

McMaster-
7998K41
Bar Made of Teflon® PTFE Adhesive-Ready Rectangular Bar, 1/8" Thick X 2" W
In stock at $13.30 per Ft.

Bondable: Etched on one side so bars can be bonded with epoxy cements and other high-strength adhesives.

Weather Resistant
Can be used indoors and outdoors. Generally withstands exposure to ultraviolet light, humidity, temperature, rain, snow, wind, and other elements. Very Low Friction
Allows objects to slide or roll easily, leading to higher efficiency, quieter performance, and less wear. Generally has a friction coefficient no greater than 0.2.

But I chose to use the BDS pads this time.

Once all the holes were drilled,

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I used my heat gun to soften the buttons on the pads to allow them to slip in easier.

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I used a large punch that just fit inside the buttons to push them in and seat them in the spring.

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Then stack the leafs together and insert the new center bolt.

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Here's another option that I may do next time I pull these apart (during the next scout rebuild)

That is to flip the bottom leaf to soften the pack up a little and make it just an overload spring.
The short leafs increase stiffness.

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Author
Bill USN-1
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Much appreciated tutorial; nice job and looking forward to completing this upgrade on my own build!
outstanding instruction
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