Broken Trailer Leaf Spring: What You Need To Do

A few weeks ago, I was driving my trailer on the highway. It was a construction zone where the pavement was not in the greatest shape. Then going over a bridge, a major bump caused my trailer and truck to bounce a lot. After pressing the brakes to slow the bouncing, I knew I might have trouble.

When I got home, I noticed that the trailer was leaning much more on one side. After a quick peek at the trailer suspension, I confirmed that I had two broken trailer leaf springs! This is a tandem trailer; both leaf springs were bent, and part of the leaf spring was broken. Luckily, I was able to get home safely vs being stuck on the side of the freeway. 

This post will share my learning experience on how to avoid and what to do if you have a broken trailer leaf spring, including:

  • Components of trailer suspension
  • Inspecting leaf spring
  • Replacement of leaf springs

Whether you have a utility trailer, a travel trailer, or a boat trailer, these principles and tips will help you stay safe on the road.

Table of Contents

Let’s start with a quick overview of the components we will be reviewing associated with your trailer suspension. 

Trailer Suspension

Your trailer absorbs the bumps in the road through the leaf springs. These leaf springs are your only connection of the trailer frame to the wheels. Any broken connection of your leaf spring components will disconnect your axle from the trailer itself. Which, of course, will leave you stranded on the side of the road with a loaded trailer stuck. 

Trailer Springs

The spring assembly comprises flexible steel plates that bend and return to their original shape. This bending is what absorbs the bumps in the road and allows for a smoother ride of your trailer and your tow vehicle.

The leaf spring is also rated for different weights. For example, if you have 3500 lb trailer axles, each leaf spring will be rated for a minimum of 1750 lbs (since you need a leaf spring on each end of the axle). The leaf spring rating is determined at the factory by the number of plates they use to build up the leaf spring.  Many trailer springs have three to five leaves instead of a single leaf. 

You usually want your leaf springs to match the same rating as your axle and trailer. Increasing your leaf spring capacity will give you a stiffer ride and cause more wear and tear to your trailer frame. So if you need to replace the springs, stick with the recommended capacity.

U Bolts

U bolts are the next most important part of your suspension. They are the mechanical fastener that connects your axle to the leaf spring. Any misconnection or loose connection with your u bolt could cause a failure to your suspension and leave you needing repair on the side of the road.


Another important component is the shackle. The Shackle is was connects the leaf spring to the trailer frame. The shackle is at the end of each leaf spring and connected with special bolts. The shackle bolt is only threaded at the end, with the middle a thicker piece of solid steel. This allows for the leaf spring to rotate and move freely as it goes up and down. A nylon bushing is also inserted into the leaf spring end to allow less friction at the bolt hole.

Inspecting Leaf Springs

 As I inspected my broken trailer leaf spring, I started to notice that there was a warning I missed. My trailer is tandem, and as I reviewed the damage, I noticed that the damaged side had more rust than the other side. My trailer is only a few years old, and nothing had rust except the leaf springs. This caused me to believe that the loaded trailer could not keep supporting the weight under a heavy load since the leaf spring was compromised by rust.

I suggest you inspect your leaf springs at least once a month if used occasionally. And inspect weekly if you use your trailer daily. Look for signs of excessive rust or any compromised metal. If there is excessive rust, either replace it or take it to a spring shop for inspection.

Look at all the connections and bolts that go to your suspension. Make sure they are all tight and no cracks or breaks need repair. Remember, each bolt has a specific task, and failure of just one bolt could disconnect the axle from the frame.

Replacement Leaf Spring

As I looked at my broken leaf spring, I knew the only option was to get replacement leaf springs. If your trailer is newer, check your warranty before buying new springs. Many manufacturers have a 5-year warranty on the axle and its parts. My axle was made by Lippert, and they sent me new leaf springs, u bolts, and nuts. Since a spring shop in my area was weeks out for service, I decided to install them myself.

Installing leaf springs is not difficult if you follow some of these basic tips.

Tip 1: Lift from the trailer frame

When you are replacing leaf springs, you need to jack your trailer from the trailer frame. You need the axle to hang freely to lower and raise the leaf spring into position.

Tip 2: Get a second jack

You must lower and raise your axle to get your leaf spring into position. I figured out the easiest way to do this is by using a small bottle jack. I have a 4-ton jack that I carry around in my truck.

Use a second jack to lift the trailer axle.

With the first jack holding up the trailer frame, use the small bottle jack under the axle to raise and lower it as needed. You will see that you need to align the leaf spring hole correctly to the shackle hole.

Tip 3: Evenly tighten U Bolts

You will likely have two u bolts on each side of the leaf spring to secure the axle. Since each u bolt has two threaded ends, you will have a total of four bolts to tighten. The important tip is evenly tightening the bolts in an x-cross pattern for even distribution. You want the leaf spring to lay flat as possible on the axle. And the only way to make sure this happens is to tighten the bolts in the x-cross pattern evenly.

Tip 4: Grease your wheel bearings

 Unless you just recently (like in the last few months) greased your trailer bearings, I suggest you take care of that maintenance item now. With your trailer jack out and trailer wheel off, this is a perfect time to take care of that all-important wheel-bearing maintenance.

Tip 5: Retorque wheel lug nuts

Also, since you took your wheels off and you are resecuring the lugs, you will need to retorque the lugs at 10 miles, 50 miles, and then 100 miles. This is important because your lugs loosen as the wheel rotates, and you will need to retorque at those intervals to keep the wheels secure. Check charts for what torque setting you will need. An overall guide is 100 ft-lb, but this can vary a bit.

Final Thoughts

Regular inspection is key to preventing and handling a broken trailer leaf spring effectively, looking out for signs of rust and metal compromise. Ensuring tight connections and intact bolts is essential for a safe suspension. Checking the warranty and consulting the manufacturer for replacement leaf springs is recommended. When installing new springs, lifting them from the trailer frame and using a second jack to adjust the axle are important steps. Evenly tightening U bolts in a cross pattern promotes stability. Lastly, allowing greasing wheel bearings during the process ensures proper maintenance. These measures enhance safety and minimize the risk of being stranded with a broken leaf spring.