U-Bolts

U-Bolts

We maintain a complete stock of leaf spring U-bolts for all types of trucks and trailers. Don’t see the size you need? We bend U-bolts for custom applications. We only use cold-drawn, stress relieved, micro-alloyed, 1541 modified steel in our U-bolt kits.

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SKU 5-0818K
$17.74

Round U-Bolt Kit with 2 Grade 5 U-Bolts that are 1/2 inches in diameter, 3 inches wide and 7-3/4 inc...   Details

Typically ships in 1 business day.
  • Rod Length:18"
  • Diameter (A):1/2"
  • Bend:Round
  • Grade:5
  • Width (B):3"
  • Length (C):7-3/4"
  • Note:Generic Images
  • MPN: 5-0818K
SKU 361-385
$33.69

Round U-Bolt Kit with 2 Grade 8 U-bolts that are 5/8 inches in diameter, 3-5/8 inches wide and 12-1/...   Details

Typically ships in 3 to 4 business days.
  • Diameter (A):5/8"
  • Bend:Round
  • Grade:8
  • Width (B):3-5/8"
  • Length (C):12-1/2"
  • Note:Generic Images
  • MPN: 361-385
SKU 5-0928K
$22.44

Round U-Bolt Kit with 2 Grade 5 U-bolts that are 9/16 inches in diameter, 3-1/4 inches wide and 10-3...   Details

Typically ships in 1 business day.
  • Diameter (A):9/16"
  • Bend:Round
  • Grade:5
  • Width (B):3-1/4"
  • Length (C):10-3/4"
  • Note:Generic Images
  • MPN: 5-0928K
SKU 8-1440K
$42.05

Round U-Bolt Kit with 2 Grade 8 U-Bolts that are 7/8 inches in diameter, 5 inches wide and 8 inches ...   Details

Typically ships in 1 business day.
  • Rod Length:20"
  • Diameter (A):7/8"
  • Bend:Round
  • Grade:8
  • Width (B):5"
  • Length (C):8"
  • Note:Generic Images
  • MPN: 8-1440K
SKU 361-426
$17.44

Semi-Round U-Bolt Kit with 2 Grade 5 U-bolts that are 9/16 inches in diameter, 2-9/16 inches wide an...   Details

Typically ships in 3 to 4 business days.
  • Diameter (A):9/16"
  • Bend:Semi-Round
  • Grade:5
  • Width (B):2-9/16"
  • Length (C):8-3/4"
  • Note:Generic Images
  • MPN: 361-426
SKU 361-430
$24.94

Square U-Bolt Kit with 2 Grade 8 U-bolts that are 5/8 inches in diameter, 3 inches wide and 9-3/8 in...   Details

Typically ships in 3 to 4 business days.
  • Diameter (A):5/8"
  • Bend:Square
  • Grade:8
  • Width (B):3"
  • Length (C):9-3/8"
  • Note:Generic Images
  • MPN: 361-430
SKU 8-1018K
$33.74

Square U-Bolt Kit with 2 Grade 8 U-Bolts that are 5/8 inches in diameter, 2-9/16 inches wide and 14-...   Details

Typically ships in 1 business day.
  • Rod Length:32"
  • Diameter (A):5/8"
  • Bend:Square
  • Corner Radius:0.250
  • Grade:8
  • Width (B):2-9/16"
  • Length (C):14-3/8"
  • Note:Generic Images
  • MPN: 8-1018K
SKU 8-12175K
$48.29

Semi-Round U-Bolt Kit with 2 Grade 8 U-Bolts that are 3/4 inches in diameter, 3-1/16 inches wide and...   Details

Typically ships in 1 business day.
  • Application:GMC
  • Rod Length:38"
  • Diameter (A):3/4"
  • Bend:Semi-Round
  • Grade:8
  • Width (B):3-1/16"
  • Length (C):17-1/4"
  • Note:Generic Images
  • MPN: 8-12175K
SKU 8-1253K
$35.38

Round U-Bolt Kit with 2 Grade 8 U-Bolts that are 3/4 inches in diameter, 5 inches wide and 9 inches ...   Details

Typically ships in 1 business day.
  • Rod Length:22"
  • Diameter (A):3/4"
  • Bend:Round
  • Grade:8
  • Width (B):5"
  • Length (C):9"
  • Note:Generic Images
  • MPN: 8-1253K
SKU 8-14220K
$57.88

Round U-Bolt Kit with 2 Grade 8 U-Bolts that are 7/8 inches in diameter, 4 inches wide and 11 inches...   Details

Typically ships in 1 business day.
  • Application:Ford
  • Rod Length:26"
  • Diameter (A):7/8"
  • Bend:Semi-Round
  • Grade:8
  • Width (B):4"
  • Length (C):11"
  • Note:Generic Images
  • MPN: 8-14220K
SKU 361-388
$46.11

Square U-Bolt Kit with 2 Grade 8 U-bolts that are 5/8 inches in diameter, 2-1/2 inches wide and 16-5...   Details

Typically ships in 3 to 4 business days.
  • Diameter (A):5/8"
  • Bend:Square
  • Grade:8
  • Width (B):2-1/2"
  • Length (C):16-5/8"
  • Note:Generic Images
  • MPN: 361-388
SKU 8-12110K
$43.79

Semi-Round U-Bolt Kit with 2 Grade 8 U-Bolts that are 3/4 inches in diameter, 3-1/16 inches wide and...   Details

Typically ships in 1 business day.
  • Application:Ford
  • Rod Length:32"
  • Diameter (A):3/4"
  • Bend:Semi-Round
  • Grade:8
  • Width (B):3-1/16"
  • Length (C):14-3/8"
  • Note:Generic Images
  • MPN: 8-12110K

How do I measure a Leaf Spring U-Bolt?

Truck and trailer leaf spring u-bolts come in all different dimensions, widths and lengths and many are custom bent, so getting your measurements correct is key.

Here is a video on how to measure U-Bolts. How To Measure Leaf Spring U-Bolts

type of ubolt bends

Step 1: Type of Bend

The typical U-bolt is rounded just like the letter "U". Yet there are a number of different of U-bolt types. The three primary types of bends are round, square and semi-round. Your vehicle's leaf spring suspension style and the shape of its parts will determine which type of bend is necessary. We do stock other types of u-bolts like Forged Bend, but they are not as common.

how to measure a u-bolt

Step 2: Rod Diameter

After you determine the bend you need, measure the rod diameter (A). The diameter can easily be measured with a wrench.

The socket sizes below will help to determine your rod size.

  • 11/16 socket = 7/16” diameter rod
  • 3/4 socket = 1/2” diameter rod
  • 13/16, 7/8 or 22mm socket = 9/16” diameter rod
  • 15/16 socket = 5/8” diameter rod
  • 1-1/16 or 1-1/8 socket = 3/4” diameter rod
  • 1-5/16 socket = 7/8” diameter rod

Step 3: Length and Width

Measure the inside width (B) and the length (C) of the U-bolt legs as well. With this information in-hand, you will be well on your way to a quick and easy U-bolt installation.


What is a Leaf Spring U-Bolt and What Does It Do?

leaf spring ubolt installed

You are not alone if you haven't heard of a leaf spring U-bolt. Most people have no idea what type of function this little part plays in the average truck's operation. Truck U-bolts are used within vehicle suspension to connect leaf springs. They offer the force necessary to clamp the leaf spring along with its related components to one another, providing a lasting attachment to the axle.

When installed correctly, U-Bolts help eliminate spring flexing and allow a vehicle to maintain its ride height and handling. A firm connection between the leaf spring and the axle seat offsets the horizontal pressure on the center bolt. If this connection is loose, the increased horizontal pressure can cause the center bolt to break, leading to leaf spring failure.

Tight U-bolts help prevent broken leaf springs. For more information, read this article on broken leaf springs and what causes leaf springs to fail. You can do your truck an enormous favor by having your leaf spring U-bolts inspected during your next service maintenance appointment.


Why Replace Your Truck or Trailer U-Bolts

Ordinary vehicle use wear and tear causes U-Bolts to stretch and lose shape or even loosen. The threads wear as they contact the Hi-Nuts. Weather takes its toll and can cause them to rust. As aging occurs, the U-bolt slowly loses its clamping function, increasing the likelihood of leaf spring failure.

Replacing U-Bolts ensures they provide adequate clamping force that safeguards against spring failure and other harm to the suspension. It is an essential component of doing a complete repair.

If you don't replace the U-Bolts when installing leaf springs, you void the manufacturer's warranty.

Most at-home mechanics can replace leaf spring U-bolts without trouble. We have a few tips to help you along the way. Read more.

Can't find the right U-Bolts for your application? We stock grade 5 and grade 8 steel threaded rods and can custom bend to your requirements.

Need Help? Call 1-800-358-4751 Today!


U-Bolts Reviews

Out of 15 reviews, the average customer rating for U-Bolts: 4.9 out of 5.

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