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Why Is Your U-Joint Failing?

Submitted by ralf on

At Belden Universal, we take pride in the expertise of our application engineers. We work with every customer to spec out the exact u joint needed for their unique application. If you’ve worked with less detail-oriented universal joint suppliers in the past, perhaps you’ve experienced unexpected u joint and driveshaft failures in your equipment.

Reasons For U-Joint Failure:

In our experience, universal joint failure typically arises from one of the following four failure modes, all of which can be mitigated by a well-selected and constructed U-joint for your specific use case.


Depending on the level of humidity in the environment, components can corrode over time, even without direct exposure to harsh substances.

Solution: Stainless Steel Universal Joints

Various grades of stainless steel joints can deliver moderate to extreme corrosion resistance. When selecting the appropriate grade, factors such as welding, machinability, and strength must be taken into consideration and balanced with corrosion resistance requirements.

Mechanical Wear

Contamination of the joint components by debris is a frequent cause of mechanical wear. Dirt can be trapped between the moving parts and increase wear on the contact surfaces over time.

Solution: Protective Boot Covers and Lubrication

Lubrication of the joint can reduce component wear; protective boots can prevent contaminants from entering and damaging the joints. Protective boot covers can keep contaminants out in addition to maintaining component lubrication. Proper lubrication can be achieved by pre-lubricating the joint, applying oil drips, or outfitting the joint with lubricant-retaining boots (bellows).

Friction and Heat Generation

Pin and block universal joints used in industrial applications often operate with friction between the component surfaces. Without proper lubrication, this friction can generate excessive heat and overheat at higher speeds. Increased abrasive wear between the moving parts can result in excessive backlash and even failure over time.


Proper lubrication helps resolve these issues. Pin and block joints can be outfitted with lubricant retaining boots or kept lubricated by oil drips. Needle-bearing joints (or Belden’s unique ‘hybrid’ pin-and-block needle-bearing joint) can be pre-lubricated and enable continuous operation at high RPM while reducing friction and backlash.

Torsional Backlash (Play)

Heavy loads, shocks, vibrations due to misalignment, and material wear can lead to loose play (backlash) within the bearings, which can ultimately lead to joint failure.


Certain optimizations, such as increasing pin diameter or reducing bore size, can reduce the amount of play present. Needle-bearing universal joints (or Belden’s pin-and-block needle-bearing joint as mentioned above) are specifically designed to maintain low backlash for critical positioning at high RPM and continuous operation.

Belden Universal Has Solutions For Your Engineering Challenges

Whether it’s corrosion, friction, heat generation, or some other application challenge causing your U-joints to fail, you can trust us to provide a solution. Give us a call today to discuss your most difficult engineering challenges and how we can help. Call us at (708) 578-6997, or feel free to contact us online.