Why can’t I reuse my U-bolts? This is one of the single most commonly asked questions out there when discussing leaf springs and related components. We get a variety of reactions when we advise our customers that reusing U-bolts is never a good idea.
What do U-bolts do for leaf springs?
Considered one of the major parts of your leaf spring installation, u-bolts will provide a permanent tie between the spring leaves and your axle. Primarily, the truck u-bolts provide the force required to clamp the leaf spring and related components firmly together.
Do you have to replace U-bolts when replacing leaf springs?
U-bolts are a vital part of your suspension system and should never be reused. Failure to replace or properly fit your U-bolts when maintaining or servicing your suspension could cause premature failure of your leaf springs or other components with catastrophic results.
Can loose U-bolts cause vibration?
By definition, an under-tightened bolt is already loose and the joint does not have enough clamp force to hold the individual sections together. This can lead to sideways slippage between sections, placing unwanted shear stress on the bolt that could eventually cause it to break. Vibration.
What is the main function of U-bolt?
What Is a U-Bolt? When you break it down, a U-bolt is a bolt bent into the shape of the letter “u.” It’s a curved bolt that features threads on each end. Because the bolt is curved, it fits nicely around pipes or tubing. That means U-bolts can secure piping or tubes to a support and work as a restraint.
What should U-bolts be torqued to?
If the U-bolts are 9/16 inch diameter, the torque specs should be between 65 to 95 foot lbs. If the U-bolts are 3/8 inch diameter, the torque should be between 30 and 50 foot lbs.
How is U-bolt strength calculated?
Multiply the product of the tensile strength and the cross-sectional area by 0.56, a coefficient which differentiates shear capacity from tensile capacity. In our example, multiplying 314.16 pounds by 0.56 gives 175.93 pounds. This number is the tensile capacity of the U-bolt.
How do you torque leaf spring bolts?
A 1/2 inch diameter bolts should be torqued between 45 ft/lbs and 70 ft/lbs. A 9/16 inch diameter bolt should be torqued between 65 ft/lbs and 95 ft/lbs and a 5/8 inch diameter bolt should be torqued between 100 ft/lbs and 120 ft/lbs.
How are Truck U bolts measured?
The length (L) is measured from end of bolt to inside of the bend, while the width (C) is measured between the legs. Some companies will show the length to the bottom or centerline of the bend instead of the top of the bend. The width is sometimes detailed as center of one leg to center of the other leg.
Can you reuse bolts that have been heated?
If fasteners have been exposed to extreme heat or show any signs of corrosion, they should not be reused. Previous modifications made to fasteners with paint, lubrication, or other treatments also make them unsuitable for a second application.
When should the U-bolts on a spring suspension be re torqued after installation?
Also, TMC recommends running the truck on a course where maximum articulation of the suspension occurs after installation, then loading the suspension before retorqueing the U-bolts. They should be retorqued again between 3,000 and 5,000 miles after replacement.
Why would U-bolts have to be tightened correctly?
centre bolts hold the spring together for assembly and help locate the spring onto the axle in the correct position. Correctly tightened ubolts are what holds the springs firmly in place on the vehicle when driving.
