Leaf Spring Suspension

[Stevetoxic]

Like some of the others - I'm following with interest.
My 59 came to me with a front disc conversion, I added Posies 3" drop springs all round and a CPP400 power steering conversion.
Its a really nice drive now - sits on the motorway at 70-80mph no problem, stops and steers straight.
I'd like the front a little lower, but do not want the expense or work involved in an independent front conversion.
There used to be new drop straight axles advertised (CPP ??) but not seen them for 55-59 trucks lately.

[speesh]

There is nothing wrong with the solid front axle, Dodge used it on their 2 wheel drive trucks up until 1971, long after the invention of freeways and interstates. I am definitely keeping my suburban stock front axle, I agree that it just seems cooler.

[1project2many]

There is nothing wrong with the solid front axle, Dodge used it on their 2 wheel drive trucks up until 1971, long after the invention of freeways and interstates

Dodge and Jeep engineering spent many years working with solid axles. The 2017 Wrangler will be equipped with a solid front axle and those trucks are far easier to drive than many of our older rigs. Solid axles can even have an advantage. In my years working with vintage race cars I learned that solid axle cars could be set up more consistently for a particular track or family of tracks as there were fewer variables to work with.

Few people think hard about what isn't working in their trucks when they complain about the original front end. The beam axle generally isn't the problem. The problem comes from asking steering components designed for stiff, skinny, bias ply tires to provide the same level of tire control as modern vehicles after switching the truck to wider, soft radials. Almost every part of the steering system (not the suspension or axle, but the steering) is going to flex when you put larger tires on. The steering arm bolted to the driver's spindle and attached to the drag link, roughly 7/8" diameter and curved, will often flex first moving like your arm as you bring a cup of coffee from the table to your mouth and back. Then the tie rod, roughly 7/8" diameter, will bow in the center. At either end of the tie rod is another steering arm which, although shorter than the arm at the drag link, will also allow some flex. All of these areas combined can cause the truck to feel sloppy and to allow it to steer the driver as the truck moves over uneven surfaces and ruts. Combine this system with wider radial tires and you've got a recipe for a truck that's more work than fun.

In order to get an idea of what it takes to tame the steering, look at the size of the components used on modern 1/2 ton solid axle trucks and compare them to our old vehicles. Tie rods and drag links are often in the 1 1/6" to 1 1/8" diameter range and steering knuckles have much larger cross sections. Several aftermarket companies are selling 1" tie rods for our trucks which can help, but the knuckles still flex. On vintage race cars we used to weld plates inside or along the edges of the knuckles to stiffen them. If welding is not an option then it might be possible to make a bolt-in brace, at least for the curved arm on the drag link side. With good front end components and good alignment angles, an upgraded tie rod and stronger knuckle make a noticeable difference.

[tsmith8]

Originally Posted by 1957 Chief

On my 49 I have a 3 inch drop axle from Sig's with all new kingpins with upgraded steering components with new roller bearings as well. I also have posies 3 inch drop springs with the upgraded shackles and what not with drop shocks. I had a professional alignment done and i don't have any issues whatsoever. Maybe a small hint of bumpsteer, but nothing like it used to have...heck it would change lanes on the road if i hit a bump.

Like Yos mentioned, I'm in it for about 1000 bucks, but my truck is stock drivetrain except with a borg warner overdrive unit.

So does this mean before you started theoretically you were lowering your front end by 6"? (3" lower springs and 3" lower straight axel) I know you old spring would of had sag and you may not have got a 3" drop with new lower springs.

I like the way your truck sits. What did you do it the rear? axel flip and/or 3" lowering springs?

Drop shocks. Are they just slightly longer shocks to compensate for for the lower front end?

[dubie]

I'm running a 3" dropped axle from CPP, Mono leafs on all 4 corners and nitro slammer shocks. We replaced all the king pins and bushings, heated and bent the steering arm to bring the drag link in line to avoid the bump steer problem and installed a beefier drag link and upgraded tie rod and ends. The truck rides and steers great. After adjusting the steering geometry this thing drives like it has power steering. And we can do 70+ MPH on the highway and le go of the wheels and she runs straight and true as anything. Yes, its nowhere near the ride of an IFS system, but it's a 60 year old truck on leaf springs, it is what it is.

[Stevetoxic]

That looks perfect Dubie.
Where'd ya get the CPP axle ?

[dubie]

i bought it from CPP when i built this truck 3 years ago.

[1957 Chief]

Originally Posted by tsmith8

So does this mean before you started theoretically you were lowering your front end by 6"? (3" lower springs and 3" lower straight axel) I know you old spring would of had sag and you may not have got a 3" drop with new lower springs.

I like the way your truck sits. What did you do it the rear? axel flip and/or 3" lowering springs?

Drop shocks. Are they just slightly longer shocks to compensate for for the lower front end?

Thanks for the props brother.

Yes, theoretically 6 inches. Pretty sure it dropped that much because my grandfather put new stock spring packs in a few years ago.

As for the rear, I had to switch it to a 55-59 rearend because I put a Borg Warner OD unit in the truck and had to go to an open driveshaft. I also added 3 inch blocks as well. And yes, the axle is on top of the springs.

Pretty sure the shocks are a lil shorter and a little more beefier.

[joedoh]

good googly moogly that is a beautiful truck

[tsmith8]

Let's do it this way. This is my truck. stock springs, stock axle. Want to lower it down about 3"...............to start.

Should i start with lowering springs or axle?
I want to fix up the front end as i do currently have some bump steer that i don't like.

As you can see the current set of springs appear to be almost flat already.

Thoughts?

[Stevetoxic]

Originally Posted by tsmith8

Let's do it this way. This is my truck. stock springs, stock axle. Want to lower it down about 3"...............to start.

Should i start with lowering springs or axle?
I want to fix up the front end as i do currently have some bump steer that i don't like.

As you can see the current set of springs appear to be almost flat already.

Thoughts?

Ground to front fender lip on my (59) truck with 3" drop Posies springs is 29" - they ride nice, very smooth, never touch the stock bumpstops.

[1957 Chief]

Originally Posted by Stevetoxic

Ground to front fender lip on my (59) truck with 3" drop Posies springs is 29" - they ride nice, very smooth, never touch the stock bumpstops.

I agree. I have a set. What makes em lower is the reverse eye on the springs.

The leaf spring bushings however are a PITA to get out...both on the truck and springs.

Bubba

[FAKKY]

Steve at industrial chassis and dakota IFS swap has been brilliant so far.... just ordered kit.
I'll get a build thread going once I start and we will see how it goes ..... but so far top guy to deal with.

[Essexeddie]

New on here and looking at this post with great interest.
My ride is a little stiff and been looking at making it softer. Looks like I may have a winter job of removing the leaf springs and clean and grease them. But at the moment I have a blown water pump issue which is on order. Keeps me out in the garage for a bit.

[yossarian19]

Originally Posted by FAKKY

Steve at industrial chassis and dakota IFS swap has been brilliant so far.... just ordered kit.
I'll get a build thread going once I start and we will see how it goes ..... but so far top guy to deal with.

Really, truly, I would love to see a build thread on this. I keep pestering Steve about details and he's been nothing but responsive and professional. I really want to put his kit in 8-lug form under the '57. Hopefully later.