U-Bolts

U-Bolts

We maintain a complete stock of leaf spring u-bolts for light, medium, and heavy duty trucks and trailers. Don’t see the size you need? We can custom bend u-bolts for every type of vehicle. We only use material that is cold drawn, stress relieved, micro-alloyed, 1541 modified steel in our u-bolt kits.

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SKU 8-1040K
$20.81

Round U-Bolt Kit with 2 Grade 8 U-Bolts that are 5/8 inches in diameter, 3-5/8 inches wide and 7-1/2 inches long.   Details

Availability: Typically ships in 5 to 7 business days.
  • Rod Length:18"
  • Diameter (A):5/8"
  • Bend:Round
  • Grade:8
  • Width (B):3-5/8"
  • Length (C):7-1/2"
  • Note:Generic Images
  • MPN: 8-1040K
SKU 8-1046K
$23.53

Round U-Bolt Kit with 2 Grade 8 U-Bolts that are 5/8 inches in diameter, 3-5/8 inches wide and 10-1/2 inches long.   Details

Availability: Typically ships in 5 to 7 business days.
  • Rod Length:24"
  • Diameter (A):5/8"
  • Bend:Round
  • Grade:8
  • Width (B):3-5/8"
  • Length (C):10-1/2"
  • Note:Generic Images
  • MPN: 8-1046K
SKU 8-1280K
$40.28

Square U-Bolt Kit with 2 Grade 8 U-Bolts that are 3/4 inches in diameter, 3-1/2 inches wide and 18 inches long.   Details

Availability: Typically ships in 5 to 7 business days.
  • Rod Length:40"
  • Diameter (A):3/4"
  • Bend:Square
  • Corner Radius:0.500
  • Grade:8
  • Width (B):3-1/2"
  • Length (C):18"
  • Note:Generic Images
  • MPN: 8-1280K
SKU 8-1287K
$36.13

Square U-Bolt Kit with 2 Grade 8 U-Bolts that are 3/4 inches in diameter, 4 inches wide and 14-3/4 inches long.   Details

Availability: Typically ships in 5 to 7 business days.
  • Rod Length:34"
  • Diameter (A):3/4"
  • Bend:Square
  • Corner Radius:0.500
  • Grade:8
  • Width (B):4"
  • Length (C):14-3/4"
  • Note:Generic Images
  • MPN: 8-1287K
SKU 361-416
$25.95

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

Availability: Typically ships in 3 to 4 business days.
  • Diameter (A):5/8"
  • Bend:Round
  • Grade:8
  • Width (B):3-1/2"
  • Length (C):8-5/8"
  • Note:Generic Images
  • MPN: 361-416
SKU 8-12185K
$41.29

Semi-Round U-Bolt Kit with 2 Grade 8 U-Bolts that are 3/4 inches in diameter, 3-1/16 inches wide and 19-1/4 inches long.   Details

Availability: Typically ships in 5 to 7 business days.
  • Application:GMC
  • Rod Length:42"
  • Diameter (A):3/4"
  • Bend:Semi-Round
  • Grade:8
  • Width (B):3-1/16"
  • Length (C):19-1/4"
  • Note:Generic Images
  • MPN: 8-12185K
SKU 8-12260K
$26.01

Semi-Round U-Bolt Kit with 2 Grade 8 U-Bolts that are 3/4 inches in diameter, 4 inches wide and 7 inches long.   Details

Availability: Typically ships in 5 to 7 business days.
  • Application:Navistar
  • Rod Length:18"
  • Diameter (A):3/4"
  • Bend:Semi-Round
  • Grade:8
  • Width (B):4"
  • Length (C):7"
  • Note:Generic Images
  • MPN: 8-12260K
SKU 8-1254K
$29.91

Round U-Bolt Kit with 2 Grade 8 U-Bolts that are 3/4 inches in diameter, 5 inches wide and 10 inches long. Kits includes 2 U-bolts, nuts and washers.   Details

Availability: Typically ships in 5 to 7 business days.
  • Rod Length:24"
  • Diameter (A):3/4"
  • Bend:Round
  • Grade:8
  • Width (B):5"
  • Length (C):10"
  • Note:Generic Images
  • MPN: 8-1254K
SKU 361-417
$23.95

Semi-Round U-Bolt Kit with 2 Grade 5 U-bolts that are 9/16 inches in diameter, 2-9/16 inches wide and 12-3/4 inches long.   Details

Availability: Typically ships in 3 to 4 business days.
  • Diameter (A):9/16"
  • Bend:Semi-Round
  • Grade:5
  • Width (B):2-9/16"
  • Length (C):12-3/4"
  • Note:Generic Images
  • MPN: 361-417
SKU 361-421
$21.95

Semi-Round U-Bolt Kit with 2 Grade 8 U-bolts that are 3/4 inches in diameter, 2-9/16 inches wide and 13-5/8 inches long.   Details

Availability: Typically ships in 3 to 4 business days.
  • Diameter (A):3/4"
  • Bend:Semi-Round
  • Grade:8
  • Width (B):2-9/16"
  • Length (C):13-5/8"
  • Note:Generic Images
  • MPN: 361-421
SKU 361-439
$27.95

Round U-Bolt Kit with 2 Grade 8 U-bolts that are 5/8 inches in diameter, 3-1/4 inches wide and 13-5/8 inches long.   Details

Availability: Typically ships in 3 to 4 business days.
  • Diameter (A):5/8"
  • Bend:Round
  • Grade:8
  • Width (B):3-1/4"
  • Length (C):13-5/8"
  • Note:Generic Images
  • MPN: 361-439
SKU 361-454
$20.95

Square U-Bolt Kit with 2 Grade 8 U-bolts that are 5/8 inches in diameter, 2-5/16 inches wide and 11-3/4 inches long.   Details

Availability: Typically ships in 3 to 4 business days.
  • Diameter (A):5/8"
  • Bend:Square
  • Grade:8
  • Width (B):2-5/16"
  • Length (C):11-3/4"
  • Note:Generic Images
  • MPN: 361-454

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

If you haven't heard of a leaf spring U-bolt, you are not alone. 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 that is necessary to clamp the leaf spring along with its related components to one another, providing a lasting attachment to the axle.

A firm u-bolt connection allows vehicles to maintain their ride height as well as their handling. The horizontal pressure placed on the center bolt is significantly offset when the spring is firmly connected to the axle seat. This allows for the preservation of the center bolt for extended operational purposes. When installed just right, U-bolts will help eliminate spring flexing.

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 Your Truck or Trailer U-Bolts Must be Replaced

As time progresses, U-Bolts rust and lose their shape, making the leaf springs fail to properly contact with other components. Or, they can simply loosen over time. U-bolts should also be replaced due to the fact that they wear throughout the course of the vehicle's operation. Stretching occurs with each drive and time takes its toll on all parts, including the leaf spring, U-bolt and beyond.

Truck owners should also know that U-bolt threads are damaged as their threads stretch when connecting to Hi-Nuts. Though it is not seen with the naked eye, this contact really does cause damage. Replacing them ensures that they will provide adequate clamping force that safeguards against spring failure and other harm to the suspension. Vehicle owners are not encouraged to reuse their U-bolts beyond the initial use. U-bolts lose their effectiveness in a gradual manner as their threads stretch when coming into contact with Hi-Nuts with each successive use of the truck. There is no getting around the fact that every truck owner should change his vehicle's U-bolts when replacing leaf springs to prevent damage and prevent a potentially bigger and more expensive problem from arising down the road.

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

We stock forged top ubolts, square u bolts, round ubolts, and semi-round u-bolts for all types of truck and trailer applications made of the finest grade 5 and grade 8 steel. Can't find the ubolts that meet your requirements? Call us at 1-800-358-4751. We can custom bend u-bolts to your specifications, and in most cases, ship the same day.


U-Bolts Reviews

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

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