Suspension Resources and Helpful How-Tos

We want to help our customers so they get the right part every time. Often that requires measuring or finding a part number. Check out these helpful sections below to learn how to measure a U-bolt, how to measure a leaf spring, and how to find the part number on your leaf spring. As always, you can reach out to our helpful and experienced staff at John’s Spring and Suspension for all of your suspension parts and service needs.

How to Measure a U-Bolt

There are many different sizes and shapes of U-bolts. The most common are round bend, square bend, and semi-round/special bend. When measuring your U-bolt, you have to take these three measurements: 

1. The width of the steel rod (figure A)
2. The interior width (figure B)
3. The height measuring from the tip of one end to the interior curve of the U-bolt (figure C)

Step 3 is especially important because often people measure to the top of the exterior curve. You do not want to go any further than the start of the interior bend. If you have any questions, bring in your old U-bolt and our expert staff will measure and make you a new custom U-bolt while you watch.

How to Measure a Leaf Spring

A leaf spring has many components to keep your truck stable and your suspension working properly. All of these components need to be measured accurately when doing a leaf spring replacement. Here are the steps:

1. Measure along the spring’s surface on the left side (figure A)
2. Measure along the spring’s surface on the right side (figure B)
3. Measure the height between the center curve and the outer curve (figure C)
4. Measure the height of the keeper in the middle-most dense section (figure D)
5. Measure the overall width of the leaf spring end to end (figure E)
6. Measure the height of the spring eyes (figure F)

Add-A-Leaf to Your Suspension

Typically the front springs are a style called “tapered leaf springs.” This means the thickness of the leaf is greater in the middle and then tapers off thinner to the end. This leaf spring acts more like a “bow and arrow” or a “butterfly” and has some give or bounce. Our suspension repair shop can add tapered leaves to a tapered leaf spring pack.

How to Find the Part Number on Your Leaf Spring

The part number for your truck’s leaf spring can be found in several places depending on the manufacturer. Here are the most common:

1. Stamped near the eye or the end of the leaf spring
2. On the side of the keeper
3. On the bottom of the spring
4. Stencil or sticker on the top of the spring