Speedy Auto > Car Tech > 4x4 > Suspension Brakes

Sprung Out: Leaf Spring Rebuild - Four Wheeler Magazine

Life is all about important decisions: What career should I choose? Should I marry this girl (or guy)? Do I want fries with that? You get the idea. And the same holds true for your build projects.

sprung Out 1978 Ford Bronco Rear Chassis Photo 41362614

This project started with a ’78 Bronco that had been abandoned. It’s very close to being a basket case, but the price was right (free), so we couldn’t turn it down. What originally began as an effort just to get it running wound up like this: Yanking the worn-out leaf springs off the stripped chassis.

One of the most common questions when building your 4x4 is which components to refurbish or rebuild and which to replace. Sometimes you choose to rebuild because new parts simply aren’t available, sometimes because you enjoy the process of making old new again, and sometimes (maybe even often) it’s because you simply don’t have the budget to buy all new stuff.

Lack of scratch was the main reason we decided to rebuild the leaf springs on the rear end of this ’78 Bronco. Hopefully, there will someday be a suspension lift in this Bronco’s future, but for now we just want to get this rust heap back together and running. After all, there’s no sense spending money on a new set of stock replacement springs if we’re going to do a complete suspension upgrade eventually. In our case, we spent less than a hundred bucks on stock replacement bushings, a new set of squeak pads, spray paint and a couple of bolts. We used Spring Service and Alignment in Charlotte, North Carolina, to demonstrate the best methods for rebuilding your springs, and the labor charge was a paltry 50 bucks, but you can save even that by doing the work yourself.

You can follow the same procedures for a leaf-spring rebuild no matter what truck you are working on and accomplish the task in your own shop or driveway. A hydraulic press is handy but not necessarily a requirement. Rebuilt springs can help provide a level, squeak-free ride compared to trying to stick it out with a worn out set of springs. And hey, who doesn’t want to save a little dough along the way?

PhotosView Slideshow Here are our springs free from their Bronco home. They are, as far as we can tell, original components, and it shows. The rubber in the bushings is rotten, the squeak pads are worn to nothing, and the rust is everywhere. In other words, they are perfect candidates for a rebuild.

Here are our springs free from their Bronco home. They are, as far as we can tell, original components, and it shows. The rubber in the bushings is rotten, the squeak pads are worn to nothing, and the rust is everywhere. In other words, they are perfect candidates for a rebuild.

We took our springs to Spring Service and Alignment, where spring specialist Michael Hardy immediately went to work on them with fire. Hardy uses a torch to heat up the wrap clips that lock the ends of the individual leaves together. After they are glowing cherry red, he opens them up with a pry bar.

The next task is to remove the center bolt. When the pressure is released the leaves can come flying apart. To reduce the chances of injuring himself before we’ve even gotten started, Hardy uses a clamping table. You probably don’t have the luxury of owning such a beast, but you can get by with a couple of large C-clamps. While he’s at it, Hardy also takes a moment to knock off the accumulated rust and scale that has collected between the leaves. A wire wheel works well, too.

Here’s what was left of the squeak pads on our springs, and they definitely need to be replaced. Each has grommets that lock into holes drilled into the leaves. The easiest way to get them off is to knock them out with a punch from the back side.

Hardy points out some significant rust pitting that can eventually lead to stress cracks. This is a concern but since we’re hoping to replace the springs in a year or two anyway, we’ll risk it.

After you complete the refurbishment, you need to make sure each leaf goes back with its original set and in the correct orientation. Hardy’s solution for marking the springs is both simple and effective. Using a piece of chalk, he marks one side of a set of leaves with a vertical mark. The other set gets a horizontal mark. Now on reassembly he just needs to make sure all the marks line up.

Old leaf springs can sag over time and lose tension, and then you’re left with a truck that rides too low or uneven. To check for proper spring arch, Hardy runs a straight edge between the center of the spring’s bushings and measures to the bottom of the center bolt hole. For the ’78 Bronco the stock spring should be between 7 1/4 to 8 inches, and we were well within tolerance. A quick Google search should help you find the stock arch-height for your specific vehicle.

If you find the springs have sagged, you can re-arch them in a hydraulic press. Begin with the longest leaf and work your way up the stack. The area most likely to have lost its arch is the longest leaf and in the area that is beyond the reach of the leaf that’s next to it—leaving it unsupported. After you finish the first leaf, work the rest so that they match the arch of the first.

On the right is the original bushing. Besides the fact that the rubber has been compromised by dry rot, the metal sleeves also have quite a bit of rust. On the left is the OEM replacement that runs about $9 each.

To install the new bushings you can get by with a hammer and punch if you are desperate, but this is exactly the type of task a large press is made for. If you know a friend that has one, now is a good time to call in any favors you might have.

Getting the bushings out of the spring shackles was a different story. On these there was no flat surface large enough to work with and Hardy worried about opening up the eye with the press, leaving a loose fit for the new bushing. So he burned out the rubber with his ever-handy torch and then cut away the metal liner.

Before reassembling the leaves, Hardy installs new squeak pads and locks the grommets in place with a light hammer tap.

Again, most of us don’t have a clamping table to hold everything in place when reassembling leaf packs, but a few beefy C-clamps should work just as well. Use a new center bolt if the old one has rust pitting (like ours) or had to be beaten out with a hammer (also like ours).

Heat up the spring clamps and lock them back down into place with a few swift blows from a hammer.

Here’s the result after about an hour in the driveway spent cleaning with a wire wheel on an angle grinder and painting with a can of Rustoleum paint. With all the pitting, nobody is going to mistake them for new, but that’s not the point. They should perform (almost) like factory fresh, and we still have a couple bucks left in the wallet for supper.

Body Chassis Transmission Drivetrain Electrical Engine Suspension Brakes Wheels Tires Tech QA

Sprung Out: Leaf Spring Rebuild - Four Wheeler Magazine

You Might Also Like

DON'T MISS