The Stovebolt Site Forums The Shop Area Driveline Questions on replacing leaf springs (1956 3200)

Hello,
I am considering replacing the leaf springs on my 56 (still original, really drops with a load in the back) and I am would like to know if I should replace both front and back, or if just the back is enough. I don’t want to change the ride height, just want to be able to haul stuff without it dragging the ground.

Thanks, Lee.

All four springs are 68 years old and have suffered the same amount of use and abuse and metal fatigue in that time.

There's no reason to suspect that the front springs aren't as worn out as the rear sporings.

I'd replace them all.

Thank you. Any special procedures for this? How do I make sure that the front end alignment doesn’t change? Are they self centering over the axle?

The replacement springs will have center bolts and the axle mount has a hole that the head of the bolt goes into. Since the springs aren't the same length from center bolt to each end, it's impossible to put them on backward (or at least it will be obvious if you attempt it.) As long as you get the center bolt head into its hole in the axle mount, you'll be fine.

You might look in your area to see if there is a shop that rebuilds the original springs.
The original ones have better metal than the aftermarket stuff and can be re-arched,
leaf's added, and tailored to your application. The cost may be less than the aftermarket
replacement ones.
Fred

Eaton-Detroit will sell you new springs or re-arch your old ones.

https://www.eatondetroitspring.com/

To think the ride height will not change with new springs after 60 years might be “optimistic”. Changing just the rears will likely raise the back and affect the front axel caster, which would be noticed in how the truck steers and returns to center.

Chuck

I figure the ride height will change since the present springs are almost flat with no load at all. That is one reason to do all four springs so it will hopefully at least remain level anyway. I have looked at lowering springs some, but I don’t want to necessarily lower the truck. At least not dramatically.

Is it worth getting the teflon sleeved springs? I need to replace my springs all around as well and read about teflon buttons or full teflon sleeves for the leaves. Seems like that would wear out pretty quick no?

The original leaf springs on my truck are 75 years old. I'm pretty sure any standard leaf springs you buy, even cheap ones from Rock Auto will outlive you.

Ditto. I got my front 22-188 dormans on my 3200 off of Amazon. Cheapest plus shipping don’t plan ong being around next time they need replacing.

I’ve got them mostly replaced; the front went fine, but the back bolts were really frozen on and I broke 2 of them getting them off. The ubolts are pretty corroded anyway, so now I wait for the new ones to get in.
I found that the left front spring had a 1/8 inch shim under it, and the left rear had a 7/16 inch shim also. Had to do some work to get it off and then drilled out to fit the pin on the underside of the new spring. Does anyone know why these were added? Or seen them on their truck?I guess an alignment issue? Just curious.

Your springs were shot. Somebody tried to even things up at some point in the last 75 years.

If those shims were tapered, they were to set caster. But that would only be in the front. Like Otto said, that shim in the rear was probably an attempt to level it side to side.

Shims on rear leaf springs are for pinion angle for drive shaft joints etc. why you would have one side makes no sense but you should check that if you removed any rear shims

I got the new ubolts yesterday so about to put the back in together. The left rear shim looks original; it appears to have been attached to the leafs when they were made. Also, the saddle that the leafs sit on are different; the right has the hole for the pin on the bottom of the leaf to drop into for alignment, but the left has a small bump that fit into the matching hole in the bottom of the shim. I had to drill out the shim to 1/2 inch so it would fit onto the bottom pin of the new leaf (the shim now has a 1/2 inch hole all the way through). I’ll tryto take some pictures before I go together with this.

It sure sounds like the spring seats (saddle) on the axle have been modified. I can think of no reason why they'd be different. Please be sure that there's a POSITIVE way to locate and retain the spring leaf pack on the saddle, not just the u-bolts. The center bolt should fit into a hole on the saddle. It's a safety thing.
The caster shims on my front axle have a pin on the bottom and a blind hole on the top for the center pin, so the spring position fore and aft is the same whether there's a shim in place or not.

Yes, the springs have a positive lock for alignment; just slightly different on both sides. If I were to remove the shim on the left side, I would have to drill a 1/2 hole in the saddle to accept the pin from the leaf spring.
A separate question: I got everything installed and was standing on the rear bumper bouncing up and down to make sure all was settled. When I looked back under the truck, I noticed that the carriage bolts in the rear shackle were bent, both sides. After looking at it all, I discovered that the second leaf from the top on the new springs was about an inch longer and closer to the end of the spring. So when the truck was on the ground, that end of the spring is now contacting the carriage bolt holding the shackle together. I could flip the shackles so the carriage bolt is closer to the bottom pivot (it is not drilled in the center), but that appears to be incorrect as far as I can tell and I don’t know for sure until I try it if that will give me enough room to clear the spring. Any thoughts?

can yopu post a picture?

Yeah those with the taper and just that carriage bolt to hold it together is a bad design.
This one with the threads on the ends are much better and can be used for those early year trucks springs.
Here are the two offered. Yes you should flip the shackle.

I’ll try to post a couple of pictures. The original springs did not interfere with the bolt, and that second leaf was about an inch shorter than on the new springs. I thought that maybe I had accidentally switched the position of the shackles, but I had not.

This might be a silly question, but did you install the spring pack backwards?

Post a picture of the entire spring pack or at least both ends (side view)...

Mike B

Looks like your shackles need to be flipped ends
Your center pin holes on your version are not centered holes on the metal. If you flip the longer side to spring it should not interfere.

Ok I went and looked at my 56 and my shackles are in the same orientation as yours. The stock leaf is just short of hitting the bolt by 1/4 inch. My second leaf definitely does not go out like yours does on either end. If you can just cut it shorter.

I bought 2 new carriage bolts this morning and installed them with the shackle holes now closer to the frame instead of the spring. The clearance is close, but it looks like it will be okay. Will need to keep an eye on it to make sure it doesn’t get worse with a load in the bed. If it doesn’t work, then I will have to try the style that has no carriage bolt in the center.
To answer Mike B, the spring ends use 2 different type of pivot pins that cannot interchange, and I didn’t try it, but I think that if you try to install the spring backwards, the center pin hole won’t line up if the front pin is installed. Or vise versa.

Does the front end of the spring pack have a shorter second spring? Could the bushings have been pressed into the wrong end or could the second spring have been spun end for end during assembly? The factory spring pack has one clip on the front half and two clips on the back half.

Mike B

Attached is a page from the 1956 Chevrolet Truck Vehicle Information Kit for the rear suspension. Earlier vehicle data indicated length from center bolt to the ends, but not this one that I can tell. It gives overall spring length of 52 inches and a measurement of 41.52 inches labeled spring centers, but that doesn't make sense that the center bolt is only about 10 inches from one end. If only one spring had the bushings installed on the wrong end, that would put the rear axle at an angle to the frame length instead of perpendicular, so it would be pretty obvious if one spring were backwards. If both were backwards it would make the driveshaft either too short or too long with everything installed.
Hope the info helps you figure it out.

41.52 inches spring centers @ measured on rear axle, could that be across the axle to the center of the spring seats?
Below is the spring assembly chart. His spring are 3712520. 52” long 26” center to center. The number 2 leaf is 25 ¼” center to center. It looks like 26”. If #2 is not 25 ¼ or #1 is not 26”, I would return them. Check the arch, you will have to remove the spring. Arch 6 5/8”

jimgmc's info indicates that the center bolt is exactly centered between the eyes at the ends, so it's possible the spring is installed backwards.

That 41.52 inch measurement could easily be the distance between spring seats.

Sorry it has taken me so long to get back; been working on a house project. Looking at the springs, it appears they are installed correctly. The lengths seem correct, and there are 2 clips at the back half with 1 on the front. The only thing different seems just to be the length of the second spring; the new one is a little bit longer. All I have had to do was flip the rear brackets to give the carriage bolt more room and so far, all is working well. Thanks to all for your help.

Thanks for getting back. A lot of times guys will ask a question get a lot of feedback but never post that all is well and what the fix was. By reporting issue fix and how it was fixed it helps others that find this thread in a search.

awesome your issues is resolved. Welcome to the 56/3200 club.