Technical Leaf spring lowering

I'm fitting a 3" dropped axle to my jailbar pickup. I'm looking to get a total drop of 4". The intention is remove 1 or 2 leaves to get a further 1".
Should i remove a longer or shorter spring?
Is it a good idea to lubricate the leaves or fit some kind of slippery material between the leaves, I intend to paint the springs packs when I'm done
Thanks
Ian

 

For "lubrication" I use the plastic spring liner material that fits between the main leaf and each spring below. Removing leafs is not the best idea but it's hard to answer without knowing how many leaves you're starting with. What I did to achieve the same result that you're after is had new main leafs made with the eyes reversed (on the underside of the spring rather than being on top).

- EM

 

I tried all sorts of leaf combos and settled on reversed main, stock 2nd and every other leaf removed. 11 leaves to 7

 

I'm hoping removing one or two leaves will soften it up a little as it currently has very little suspension travel
Ian

 

Long leaves carry the weight and the short ones stiffen the spring.

 

Right, so which would lower it a little?
Ian

 

It's a trial and error process.
In general:
If you remove longer leaves (and leave shorter leaves in place), the spring will be lower & stiffer.
If you remove shorter leaves (and leave longer leaves in place), the spring pack will be lower & softer.

I assume you've already reversed the eyes on the main leaf? That's usually done first, before experimenting with leaf removal, and lowers the car about an inch.

 

I haven't reversed the spring as yet, I want to lower it and soften it a little
Ian

 

Reconditioning a early Ford spring.

First, inspect the top of all the leaves for grooving.
If grooved, grind and taper the tops of all the leaves
for the last 3 inches.
The number of leaves you use will depend on the final
weight of the car and the "ride" you want. On a typical
early Ford it is possible to get a 100 lb. per inch spring
rate which will give a very comfortable "touring ride".
Have the shocks disconnected when checking spring rates.
The easiest way to check spring rate is measure the height
of a point on the front bumper. Apply a known weight to
the front bumper such as a 200 lb. person. Measure the
same point again. Say it went down 2 inches. You have
roughly a 100 lb per inch spring rate on the front.
DO NOT USE GREASE BETWEEN THE LEAVES. It will only attract
dirt and then you have grinding compound. I Parkerize
the leaves (optional) and then spray them all over with
SlipPlate (trade name) which is a graphite spray or
Moly Kote (trade name) which is a molybdenem disulfide
base spray.
DO NOT PAINT ANY PART OF A SPRING. The graphite or Moly
spray will stop rust. Slip Plate can be had at John Deere
dealers. Moly Kote can be had at auto parts dealers.
I use 1/16 UHMW plastic between the leaves.This is the
same as Teflon but about 1/3 the price. This is optional
but really decreases friction and prolongs spring life.
After determining the final configuration of the spring
I wrap it with black electrical tape from the eyes to
the U bolts. This keeps dirt out. There are commercial
spring covers available also.
If you use a reversed eye main leaf, be sure the second
leaf is short enough that there is no way it can bottom
on the eye when at full compression.
Sometimes the original spring clips will not reach over
the spring after the UHMW is added.
It is a simple matter to fabricate ones that will.
The inside top of the cross member where the spring seats,
usually has a radius.
BE SURE the top leaf of the spring has a radius to match.
A sharp corner on the spring leaf can cause a cracked
cross member.
I use moly filled Delrin shackle bushings because they
have almost no friction and they never wear out.

 

post some pics of what you are working on

 

I removed the mountings on the rear leaves and intend to remount them 2 1/2" higher and then remove leaves to hopefully get 4-5" of drop
Here is my rear leaf pack, I hope to get around 2-3" drop, how many leaves to take out?

 

It is not a cut and dried process. Each spring is different...To get in the ball park try removing leaf 3-5 and 7 numbering up from the bottom. Do not remove number 2 under any conditions.

 

That's interesting, I was thinking of removing every other leaf, what's the deal with number 2?
Ian

 

Ian,

I am interested to hear the answers to this as well. If I understand what you are asking you're looking for information on how your spring pack will respond to leaf removal WITHOUT doing any other work such as reversing the eyes on the main leaf. Correct?

I need to lower my '47 Tudor and eventually will add a dropped axle. But for now I want to remove a few leafs to lower the car as much as possible without doing anything else at this time. Thanks for asking your question on the forum.

Thor

 

I'm saving the reverse eye mod! If it isn't low enough I will reverse eyes front and rear
Ian

 

The main leaf and #2 have the most strain on them. If either one fails you can get the car stopped safely. If you remove #2 the main leaf is doing all the work. If it fails you are as they say in railroad
talk, on the ground.
If you go to a reverse eye main leaf, be sure the ends of the second leaf absolutely do not touch
the eye of the main leaf at full compression.

 

UHMW Polyethylene is not Teflon.\

The cheapest, but not the easiest way to do this is to hunt up an old 150 pound or heavier blacksmith anvil and a 3 to 5 pound blacksmith hammer and reverse bend each leaf by beating on them until they bend the way you want them..

Just walk the hammer down the center of each leaf as you watch your blows carefully bend them.

It won't take much to do this and if you are lucky enough to find or know an old Blacksmith, he can help you do this in several hours..

My old Blacksmith Buddy taught me this back when I was a pup in HS...

I figure a commercial spring repair shop nowadays will use a "cold roller" or maybe a "trip hammer" instead of a blacksmith hammer to do this easier and faster.. BUT it still is kind of an art. You know, onna those "feelie" deals to get the drop you want..

pdq67

 

"UHMW Polyethylene is not Teflon.\"
You are right. I should have said it has similar characteristics for the application we are talking about.
They are both very low coefficient of friction materials.

 

Isn't it easier to use a jig and a small bottle jack to rebend the spring? Haven't done it but seen a few posts and vids on the subject
Ian

 

I used a HF press to flatten the main leaf in my '37. Just marked it off in 3" segments and put the same number of pumps at each location. (Go easy at first, you'll get the hang of it) First one took about a half hour, second one about 15 minutes.
Straddle the press frame and let the jack do the work.

 

I am now ready to refit the front axle(had the kingpins fitted today)
Have a 3" dropped axle from Sid and want a further 1-2". The front leaf pack has 7 leaves, I initially removed number 2, now I wonder if that is wrong and maybe I should refit no 2 and remove no 1
Not a big deal removing leaves later but would be nice to get in the ballpark initially
Thanks
Ian

 

Finally back together. Not super low but looks so much better

 

Front suspension is very firm, make that very very firm!!
I have only removed the shortest leaf, should I put that back and remove a longer one? Don't mind if it drops a touch more but would like to soften the ride
Ian

 

Looks good, I just installed a 4" dropped axle from Sid as we'll and removed two leafs (1&2) but now I'm starting to second guess removing them.

 

Wondered if I should have used a 4" drop but then I would still need to remove leaves to soften it.
Would be interested on pics with that axle,how did you do the rear?
Ian

 

3" blocks on rear no leafs removed.

 

What year truck is that on? Blocks wouldn't work on mine
Ian