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Jun 7th 2021

What to Know About Replacing Trailer Leaf Springs

Leaf springs give your travel trailer much-needed cushioning against bumps and vibrations, but they are not one-size-fits-all. Different vehicles call for different leaf spring types and sizes. The wrong leaf spring leaves your vehicle unprotected and misaligned. Before you can replace your leaf springs, you need to measure your existing ones to know what type of replacement part you need.

Here's everything you need to know about replacing travel trailer leaf springs.

When to Replace Leaf Springs on a Trailer

Weather, aging and weight overload can deteriorate your springs over time. Inspect the leaf springs on your trailer at least once every 12,000 miles or when you notice any sagging, corrosion, cracks or uneven riding. As you inspect, look for the following:

  • Look at each eye of the spring and note any cracks here and near the mounting plates.
  • Check for corrosion and rust on all sides of the spring.
  • Assess any gaps between leaves, which indicate wear and overload.

Wipe your leaf spring and mounting plates clean and pat them dry regularly to minimize the chance for buildup. Lubricate them as needed to prevent premature wear and increase their longevity.

How to Measure Trailer Leaf Springs

The center bolt of your leaf spring is known as the center point. Most leaf springs have two eyes at each end, where the bushings are. Some leaf springs have hooks or flat ends. Follow these steps to calculate the right size spring for your replacement:

  • Jack up your trailer: Jack up your trailer far enough that the axle is hanging freely, and you can comfortably remove and replace the leaf springs. Do not place the jack on the suspension.
  • Remove the spring: The most accurate way to measure a leaf spring is without any load-bearing on it. Remove and measure one spring at a time so the other spring can keep the suspension in place. You may need special tools to remove damaged nuts, bolts and mounts.
  • Measure the length: Measure the spring's length with a standard tape measure placed from the center of one eye to the center of the eye on the opposite end. 
  • Measure the width: Measure the width by placing a tape measure from the bottom of the bottom leaf to the top of the top leaf.
  • Take A and B measurements: Your A and B measurements are the length between the center point and each eye. For example, the A measurement is the length between the center point and the eye on the right side, while the B measurement is on the left.
  • Measure the arch: The spring arch changes over time, so measuring it is a good way to understand how it wears down and what size to look for as a replacement. Flip the spring upside down and use a standard tape measure to measure from the floor or table to the first leaf.

How to Choose Replacement Trailer Springs

Always replace your trailer springs in pairs for a balanced load. Choose your replacement by noting your axle capacity, the number of leaves on your existing springs and what type and size your springs are.

Axle Capacity

Most vehicle axles have the capacity rating listed on a sticker or plate, but you can also check in your owner's manual. Some manufacturers may also have specific axle information available on their websites.

Number of Leaves

While you measure the spring, count how many leaves are on it. The more leaves it has, the more supported it is — but too many leaves will make your suspension too rigid. Leaf springs are typically mono-leaf, meaning they have only one leaf, or multi-leaf with clips between each layer. There should be no gaps between multi-leaf springs.

Spring Size and Type

Once you've removed your leaf spring, figure out what type you're working with. Common types of trailer springs include:

  • Double eye springs with both eyes open
  • Slipper springs with an open eye on one end
  • Slipper springs with a radius end
  • Slipper springs with a flat end
  • Slipper springs with a hook end

In some cases, you might only need to replace the bushings if your springs are still intact and aren't buckling, corroded or elongated.

Tools You Will Need

The tools you need depend on the reason you're replacing your spring. If your current leaf spring is corroded or rusted, deteriorating or otherwise stuck in place, you may need a rust penetrant, a pry bar, a heat torch or a grinder to remove it from the mount. 

Have the following items on hand:

  • New U-Bolts
  • A torque wrench
  • Sockets
  • An extendable ratchet
  • A breaker bar or pry bar
  • A jack and jack stand
  • A hammer
  • A grinder or wire wheel
  • A standard tape measure
  • A soft tape measure
  • Wheel blocks for your front wheels
  • Twist sockets
  • New bolts and nuts
  • Rust penetrant and sealant
  • Thread locker
  • Safety glasses
  • Safety gloves
  • A dust mask

Always wear personal protective gear while removing and replacing your leaf springs, especially when rust and dirt are present.

Tips for Replacing Leaf Springs

Fortunately, replacing your leaf springs is easy once you have the correct replacement. Here are some tips to help you through the process:

  • While you should always install new U-bolts and fasteners, you can reuse the mounting plate if it's still in good condition.
  • Use a torque wrench to tighten the U-bolts and check with the U-bolt manufacturer for specific torque measurements.
  • Keep a pry bar on hand to help remove challenging bolts.
  • Treat your trailer's underside with rust removal and an anti-rust coating to protect it from future damage — wait 24 hours after treatment to resume spring replacement.
  • Use thread locker adhesive to help keep new bolts in place.

Shop Leaf Springs

Shop Replacement Leaf Springs at General Spring KC

General Spring KC has specialized in supplying durable, high-quality leaf springs and accessories for truck and trailer owners since 1965. We have leaf springs compatible with all major vehicle manufacturers, including Chevrolet, Dodge, Ford, Jeep, Toyota, Mercury, and Nissan. Replacing your leaf springs yourself? You can also shop our selection of U-bolts and fasteners to help you secure your new spring and enjoy long-lasting support.

Contact a representative to learn more about measuring for and choosing the right spring for your vehicle, and shop truck and travel trailer leaf spring replacements today to take advantage of our one-year warranty program on all new leaf springs.