The Stovebolt Site Forums The Shop Area Driveline A couple 3100 leaf spring questions

FINALLY getting around to putting the new rear leaves and shackles I bought months ago. Have one side completely disassembled.

This is a later 55-62 style rear open driveline that was fitted to the truck decades ago.

1). The springs I got from STL spring have the nut on the top side and the round pin on bottom. That’s opposite the springs I’m taking out. As long as the nut fits into the hole on the spring perch….does it matter?

2). I ~think~ someone (Jon G?) mentioned a while back that I should have a rubber pad between spring and perch. Can anyone confirm?

I'm not talking about the shackles, their mounts, the spring eye bolt and it's mount.

Your 51 originally had leaf springs with a pin that goes through the leaf pack and the end of the same pin fits a hole in the bracket welded to the rear axle. This pin helps keep the spring pack in place. With a donor rear axle, you typically dump the original design out the window along with your 1) and 2) above. Usually the later year donor axle design spring mounts don't work with the original springs so these axle parts are usually ground off and a new weld-in mounting kit is used. Some can have home brew designs (close eyes and not look at). You purchased new springs for a different generation of trucks which adds yet another complication factor.

I would go back to the spring vendor and tell them what year/model rear axle you have and ask what they recommend for installation parts or kit. If you want Stovebolt members to help, you need to identify what axle you have, what model number STL springs you have and provide pictures.

I should ask that question a different way.

The round head of the center bolt should really face the axle mount. In this case, the spring and perch are below the axle, so the round head should be on top of the spring pack.

These were provided with the nut on top rather than the round head. Perhaps by mistake. So can a guy just remove and reverse the center bolt on a set of brand new springs?

Sure can. A couple of C-clamps will be your friend.

A rubber pad (can be made of the sidewall of an old tire) between the spring and perch will reduce sound emanating from the differential...but as I hopefully said earlier, it is mandatory the locator pin mate with the hole. These were used on lots of GM vehicles. Somewhat less important in an old pickup, however in a unibody car (like the Camaro) if you don't have these you probably won't like it: https://www.camarocentral.com/1967_1969_Multi_Leaf_Rear_Spring_Rubber_Mount_Pad_p/sus-150.htm

If you're removing and reversing the center bolt, please note: many spring makers stamp the top of the bolt (above the nut) to keep it from ever coming loose. If that is the case with yours, you'll need to buy new locating bolts / nuts as the threads will be damaged when you remove them.

I bought a foot of baler belting. I’d say it’s 3/16 thick and should allow plenty of pin to locate to the perch.

First bolt reversal was going fine until I got a little too zealous with the torque. It stripped. No one in town stocks 5/16 center bolts so I guess now I wait. The big “O” has a couple ordered for me.

I believe I've cheated before with allen drive cap screws.

Might be my imagination. But the leaves in the one I was fooling with, seems to be not be as neatly on top of one another as they were before. The 4th one from the bottom, is sitting off to one side maybe 1/8 to 1/4 inch.

Can I clamp the stack in the vise and try to straighten it back up? Not worry about it?

If the center bolt went back through them all, I don’t know why it would have moved.

Did you by any chance rotate that leaf 180 degrees?

Never took the pack apart. I C-clamped them together and reversed the bolt.

Best theory I got:

The center hole in that one spring was egg shaped and it shifted a bit when pin was driven back in.

Best plan I got until someone hatches a better one:

C-clamp leaves together. Drive out center bolt. Place stack in vise and try to re-align the stack. Drive new center bolt while stack is clamped from sides in the vise. Maybe try to tighten tip the leaf clips/clamps somehow. (Could definitely use some pointers on that process).

That's a good plan. The hole in the leaf will be slightly larger than the bolt but it should not be enough to allow for 1/4" of movement. If that's the case I'd say somebody at the spring place made a boo-boo. In some springs (by design) the hole is not exactly in the dead center of the leaves, however. That isn't uncommon, although I can't remember if any of the AD springs were made that way. If so, all leaves will be drilled off-center and the easy way to keep them straight is to draw a line from top leaf to bottom with a Marks-A-Lot before doing anything and then follow that when re-assembling. The clips/clamps don't need to be tight. They just need to be secured to the upper leaf so they provide a sideways limit and don't rattle. If they aren't attached to the leaf and if they're too tight around the leaves, they'll creep forward bit by bit as the spring leaves flex and soon will be doing nothing but rattling around. I've seen guys use radiator clips on them and those never work. JC Whitney used to sell some very good ones which were spring loaded with rubber pads so they would stay put...but those are long gone. Good luck!

C-clamp, remove center bolt, find a rod or tool that will fit somewhat snugly in the hole. Loosen C-clamps slightly. Push on rod until your hole lines up the way you want it to. Tighten C-clamps. Recheck straightness with rod. Looks good? Replace bolt. Doesn't look good? Repeat process.

You seem to have first hand experience with this exact scenario….

I've done one or two.

Just so I can understand correctly, is your 1/4" overhang at the center bolt or out on the ends of the leaf?

Mike B

Excellent question. I hadn’t looked at it that way before.

It’s out at the ends. And both ends hang over on the same side of the pack, so it’s not just twisted.

Perhaps it was always like this and nothing to do with my bolt replacement?

If the entire length of the spring is hanging over the rest of the pack by 1/4" then the center hole could be offset. What happens if you spin that leaf 180*...does that take care of the issue?

Mike B

It’s not hanging over the entire length. It’s more or less aligned at the bolt. Gradually more overhang as you progress toward each end.

I’m inclined to think that leaf always just had a little sweep to it. Not sure what I’d have done to cause it.

How close is the other side of the curve to being "normal" looking? If it's close, I'd leave it alone. The U-bolts along with the clips are what keep the leaves inline, if they are in good shape you should be fine.

While you had it apart did you look for cracks? The leaf in question could be cracked half way to the center bolt allowing it to now be curved as it opens up...

Mike B

I didn’t have the pack apart. Just clamped it together and reversed the bolt.

If I was to take it apart to inspect…just pry the clips open I guess?

You might be able to see a crack without taking it apart or see a rust streak running down from it. Use a bright light and look close right where the center bolt is located...

Mike B

Pics of the ornery leaf. For reference, the one immediately above the crooked one is in line with the others.

Hmmm. Those leaves should sit flat and straight as can be when assembled. Something is amiss there. Where did you get those?

Based on the spacing to the end of the adjacent leaves, I think that one is assembled 180 degrees out. The center bolt isn't in the true center of the spring pack (lengthwise).
Do the ends of the offending leaf match the position on the other spring? Try spinning that leaf 180 degrees.

The leaf with the red X will hit the rebounding clip when the rear axle moves up.
Definitely in the wrong position.

Yes, it obviously will. I asked if the leaves had been rotated, but the answer was no. So...?

Center bolts are in at the parts store. I will disassemble as needed and inspect/ correct. Perhaps we will find our answer.

Unless I physically drove a new hole in that spring while reversing the bolt the other night….I’m struggling to explain.

However, as much as I’m a newb to the world of leaf springs, I do think I would have noticed the cockeyed leaf earlier. I bought these things from St. Louis Spring and Brake months ago. Maybe even a year ago.

My first experience with leaf spring disassembly and reassembly was around 1965. The only time I have seen something like this was if the center hole wasn't "centered" in each leaf and I or somebody else put them back together all wonky or if the leaves had been damaged somehow. When you get them apart, look and see. It is really difficult to tell from just your images, but it almost looks like those leaves are twisted or something. And I can't imagine how a spring shop could have done that, but they aren't sitting as they should. Please look at the attached image. This spring was taken completely apart and cleaned...I bought it new many years ago but it had sat around a while and picked up some rust and I wanted to see if it needed attention.

When I say damaged, I mean in 1967 I helped a friend work on a Jeep that had fallen on top of a large rock coming down a mountain. The impact had ruined one leaf spring and it looked sort of like yours. Just couldn't be made right without some serious work.

What's the other side spring pack look like...is that same leaf almost hitting the clip?

If you measure from the end of the spring to the center bolt is the distance the same on both ends?

Mike B

I’m leaning heavily toward it being ME that screwed up the spring. But my simple brain can’t yet figure out how.

The retaining clips, are they typically riveted through multiple leaves or just one and then wrapped around the others? Can I just secure the stack with a clamp and pry them open to disassemble?

In an interesting side note, the image on Jim Carter’s website of the 1/2 ton leaf spring has the st Louis spring stamping. And it also has the center nut on the top (wrong) side of the stack. This place has an excellent reputation and I’m not trying to defame them. Just wondering if there’s a backstory here.

Yes, the clip is riveted through one spring only. That spring has a faired hole that the rivet in crushed into and then ground smooth so it won't dig into the spring above it.

You can open the clip if needed, but it might be easier to do if you heat the clip red hot at the bend first. The clips should have a loose fit when folded over, the springs need to be able to move.

Mike B

Don't pry open the rebound clips. During assembly they may have been heated to make them pliable for bending but the metal may temper as it cools. You can break the clips trying to open and squeeze them back into place. Please post a picture of the whole spring so we can see the pin and orientation of the leaves. The two shortest leaves do not have rebound clips. They are held in place by the U-bolts once the springs are installed.

The springs are new. If they are assembled wrong they need to be returned or get a refund.

Update:

Long story short, that leaf must have been out of position when they drilled it. If I remove the center bolt, and clamp the stack in my vise to true it up to the others, the hole doesn’t line up.

I also tested the theory that it moved to one end when I first reversed the bolt and that nut stripped. Thought maybe I punched an entirely new hole with the new hardened bolt. (Unlikely, I know) So I tapped one end of the leaf with a socket extension and a BFH to make it the same distance from the clip as the “good” one. No hole there. Furthermore, the post assembly paint job they did shows where everything was when I got them.

As to where we go from here:

1) Best option but the one I dislike the most - find a day to drive two hours one way to STL and have them fix it. I just want to get this job done and get on with my life. Not sure when I will find time to get to STL.

2) Position offending leaf correctly and drill a new hole. I’m sure that’s not a great idea.

3) Grab the corresponding leaf out of the original spring, clean it up and replace. Probably no guarantee it would line up perfectly.

4) Compare old springs to new to make sure they aren’t de-arched. Put one old spring back in service. Clean up, replace bushings, repaint and install.

Need a beer….

It's been asked twice whether the offending spring is the same as the other side spring pack. Did you check that?

Also, did you try spinning that leaf 180 degrees? If all the other leaves are drilled offset from center (to one side), then turning that leaf around might make it line up. Is the offset leaf held in place by the clips? It looks like it might be one of the shorter leaves that isn't clipped in place. If that's the case, it would be easy to turn around. Clamp, remove center bolt, install all-thread and loosen so the leaves are loose, turn that leaf and see what happens. If it's better, tighten the nuts on the allthread, reinstall clamps, and replace the center bolt.

Don't try drilling a new hole in that leaf. You'll probably burn up a couple drill bits, and the leaf will be weakened.

Sorry,

The offending spring is about 1.5 inches shifted out of place if you compare it to the other “good” spring.

The offending spring IS retained by the clips and I didn’t try to unclip and turn it 180 because some suggested that was not a good idea. I’d gladly try it if there’s a general consensus that’s fine to do.

Edit: just measured center to ends of that leaf on both springs. Pretty sure the spring shop just put that one in backwards.

From the pics you posted, it didn't look like it was retained by the clips, but hard to tell for sure.

I don't think you'd have an issue with unbending the clips and rebending them. You shouldn't need to heat them, as they're mild steel, but some heat might help get them back in place.

If the shop screwed up, you should be able to get them to replace it, but I wouldn't be afraid to try spinning that leaf. Even if it doesn't work, they'd probably replace it if you document the as-received condition.

I’m sure they’d make it right. Really cool, historic shop and nice folks. I just don’t want to make the drive and want to put my truck back together.

I’ll probably try to spin that leaf around and report back. Just bang the clips back into the same place when I’m done? No need to get them especially tight?

Why drive? Call them up and tell them you're shipping it to them UPS and they can reimburse you for it and ship the new spring back at their expense.