The Easy Guide to Replacing Trailer Leaf Springs

Time to replace the worn or broken leaf springs on your trailer? You've come to the right place! Replacing trailer leaf springs can seem like a daunting task. One look underneath your trailer and the questions begin to arise: Where do I even start the process of how to change leaf springs? Do I have to dismantle my entire trailer axle to get at these things? Do the springs come apart individually or as a complete set? Will I finish the job in time for my next road trip?

We’re here to tell you that trailer leaf spring replacement is actually quite easy, far easier than replacing coil springs. Maybe that sounds pie in the sky, but it’s true! In this guide, we’ll walk you through the complete process of replacing your trailer leaf springs, and show you just how simple it can be with some common tools and a little DIY spirit.

Always remember, if you aren’t confident about your ability to replace your leaf springs, there’s no shame in seeking professional assistance. There are countless shops and installers that can quickly help you get your leaf springs replaced and get your trailer back on the road.

As mentioned above, replacing trailer leaf springs only requires a few tools common to most DIYer garages. This is because trailer leaf springs are mounted with really only a few nuts and bolts. If you don’t have the necessary tools, consider renting or borrowing from a friend.

Before installing your new replacement trailer leaf springs, ensure you have the right tools set aside. Always refer to the owner’s manual from the manufacturer for specific tools and instructions for your setup.

1. Floor jack
2. Jack stands
3. Impact driver or ratchet
4. Socket set
5. Box-end wrenches
6. Mallet or hammer
7. Torque wrench

Whether you’re replacing slipper springs on your RV or double-eye springs on a small utility trailer, the following steps will walk you through the general process to install leaf springs on your spring suspension trailer. Before you begin, make sure your trailer is parked on a level surface and that the wheels are properly chocked.

Use your floor jack to jack up the trailer frame. The aim is to lift the trailer enough to get the tires off the ground.

Then, use appropriately rated jack stands under the frame and axle to keep them suspended. This is to alleviate stress on the shackle bolts (the hardware connecting your leaf springs to your trailer -- not to be confused with eye bolts!), so it’s easier to remove them when the time comes.

Start by lifting and securing one side of the trailer, followed by the other.

Remove the wheels from the axle, both the curb-side wheel and road-side. Loosen the lug nuts with your impact driver or ratchet. Once removed, set nuts and wheels aside for later.

With the wheels removed, you should have a better visual of the trailer suspension system and particularly the leaf springs. The hardware that connects the ends of each leaf spring to the trailer frame are called shackle bolts.

Hold the head of the shackle bolt with a box-end wrench and use your impact driver to remove the nut. Once the nut is off, you can tap the bolt out with a mallet or hammer until is unseats from the hanger. You may need to use a punch to drive it all the way out.

As you remove each shackle bolt, inspect the threads for damage. If damaged, you’ll need to replace the bolts. Otherwise, set them aside for later reinstallation.

Remove the bolts holding the leaf spring to the equalizer as well, if present.

Now it’s time to remove the leaf springs! The leaf springs will be held in place by U-bolts that wrap around the axle beam.

Start with the nuts. Remove the four nuts and washers securing the U-bolts to the leaf springs. Then, remove the U-bolts and the tie-plate. You may need to use your mallet again to tap the hardware out of the mounting holes. Also, be sure to replace the U-bolts with new U-bolts.

Finally remove the leaf springs.

You're halfway there! Hopefully at this point, you're beginning to realize that installing leaf springs is easier than expected!

To install your new leaf springs, place the spring pack on the axle, making sure the leaf spring clips (the metal clip holding the pack of spring bars together) are pointed toward the front of the trailer.

Place the tie-plate on top of the leaf springs, making sure the center button on the spring pack engages with the hole in the center of the tie-plate.

Position the U-bolts on the axle, passing the threaded ends up from the bottom and through the holes in the tie-plate. Use a hammer if needed to tap the U-bolts into place. Fasten the U-bolts with washers and nuts, hand-tightening the hardware until snug.

You also need to verify the following at this time:

• The center button in the spring pack must be engaged in the tie-plate.
• The leaf springs must be square to the axle.
• The U-bolts must be straight up and down and not splayed in or out.
• Each U-bolt must have approximately the same number of threads sticking out of each nut.

Finally, torque the U-bolts to the proper specifications, using a star or crisscross pattern.

Apply grease to the shackle bolts before inserting them into the leaf spring eyelets, hanger brackets and equalizers. Tap the bolts into place with your mallet if needed. If you’re using wet bolts (that is, bolts with a grease zerk), use a nut over the grease zerk to protect it while tapping.

Also, it’s worth noting that the shackle bolts that connect the leaf springs to your equalizers can be tricky to install. You may need to adjust the position of the axle to get the holes lined up.

Tighten down all hardware by hand first and then torque everything to the proper specifications.

With everything properly torqued, replace the wheels on the axle hubs. Start all lug nuts by hand to prevent cross-threading, and then tighten them in a star pattern.  
Finally, lower the trailer, making sure to remove each jack stand, and torque the lug nuts to the final specs.

Congratulations on a successful trailer leaf spring installation! Now get out there and enjoy the journey.

Disclaimer: These photographs, recommendations, and approximations are intended for demonstration purposes only and do not reflect the specifications of any particular tow vehicle, recreational vehicle, or trailer. Always consult the manufacturer’s Owner’s Manual.