U-Joint Phasing

Having sufficient knowledge about U-joint phasing is important especially when you’re doing maintenance in your vehicle’s drive shaft. Learn more about it by reading until the end of this article. Stay informed.

What is U-joint phasing?

U-joint phasing happens when the yokes or universal joints are set in exactly the same angle or plane as their shafts. Once a U-joint phasing malfunctions, the car may lose its control, leaving the driver helpless and prone to accidents.

There could be numerous unpleasant consequences. To guarantee safety while driving, it is better to understand what triggers a U-joint malfunction. This article will teach you more about U-joint phasing and to prevent its possible failure.

What is a Universal Joint?

A universal joint or U-joint is also known as Hooke’s joint, it is a coupling or a joint that connects stiff rods with angled axes and is often employed in shafts that convey rotating motion. It is made up of a set of joints that are close together and positioned at ninety degrees towards each other. They are joined by an angled shaft. Furthermore, a U-joint is not a joint that has a constant velocity.

These U-joints are widely utilized for distinct purposes, including vehicle drive shafts, machinery for industrial operations, and other mechanical systems requiring an adaptable components connection and durability.

What causes U-joint to be out of phase?

U-joints are made to function through angles with a specific range. Whenever the angle of the U-joint is excessively steep, it can put too much tension on the U-joint, causing corrosion and ultimately lead to damage.

Gathering alignment data before removing or disassembling equipment, even if the repair is undertaken for non-aligned factors may indicate underlying causes of U-joints to be out of phase over time.

Regular inspection and documentation of the alignment problems provide beneficial details on reversible conditions that, if handled well, can lessen errors, boost efficiency, and reduce the potential costs.

What happens if U-joint is out of phase?

When your vehicle driveshaft’s U-joints are out of phase, they will rotate at different rates during every turn, causing 2nd order vibrations or noises. Universal joints or U-joint vibrations may lead to inevitable damage to the driveshaft, intense wear, and etc.  Inaccurate phasing can create possible serious injuries when the U-joint hits failure.

What are the symptoms that show U-joint is out of phase?

During the vehicle’s driveshaft maintenance, you must check if the U-joint is in or out of phase. Check the following 5 symptoms below if your vehicle’s driveshaft is experiencing them.

Five Symptoms That Show U-Joint Is Out of Phase

• Premature failure of the seal, bearing, coupling and bearing
• Extreme vibration
• Squeaking noise
• The shaft parts fail to function
• Excessive oil leakage at bearing seals

5 Ways to Check If U-Joint Is in or Out of Phase

Here are 5 ways to determine whether your vehicle driveshaft’s U-joint is in phase or not.

1. Compare the yokes on both ends of the driveshaft to see if they are in the same plane or angle.
2. Look for the serial numbers and check if they match.
3. Check for alignment arrows that indicate proper positioning of the two ends of the driving shaft.
4. Look for an imprinted arrow inside the tube that should line up with each component of the driveshaft. It will show alignment and accurate phase with how it is balanced at the manufacturer.
5. The joints on a two-piece driveshaft installation that connects the gearbox (the auxiliary or main) leading the rear axle should be constructed “in phase” otherwise indicated by the manufacturer of the vehicle.

Tips for Proper U-Joint Phasing

For further knowledge and more important tips, learn from the following guide below to guarantee proper U-joint phasing.

• During U-joint installation, make sure that the inbound and outbound shaft functions at near-constant velocity. It’s crucial to lessen vibration, noise, and possible wear.
• Part of the proper phasing is ensuring that the center lines of the transmission and the rear axle drive shaft are parallel to each other. It can be placed either high or low, however, it needs to be parallel.
• In some cases, U-joints are at a severe angle although they are properly phased. You can feel a hard spot in the steering for no reason. When instances like this occur, you can fix it by indexing the U-joints at 2 or 3 splines in a single direction, then the hard spot will be gone or minimized.
• If you’re experiencing serious issues with a U-joint, then it is recommended to have a replacement. When replacing a U-joint, you must know the cause of the recent U-joints failure. For instance, when your vehicle’s engine or suspension has been modified, you should avoid replacing the OE U-joint with another OE-spec unit because it won’t solve the issue.
• Moreover, U-joint lubrication is necessary to extend its lifespan. Without regular lubrication can lead to frequent U-joint failure and costly replacement.
• Reach out to a trusted shop to double check and verify if your vehicle’s drive shaft is properly balanced or if the U-joint is properly phased.

FAQs

What is a common cause of universal joint failure?

One of the most common U-joint issues is torsional backlash. The usual causes of torsional backlash are shock vibrations due to misalignment, heavy loads, and wear of the components. This backlash happens inside the bearings.

Is it necessary to have the same angles at both ends of the Universal joint?

It mostly depends on preferred setup. But it’s recommended for U-joint to have exactly the same angle. However, if you want to set them in different angles, you can do so as if you’re doing an experiment to see if it works.

When should you replace a Universal joint?

Universal joints have a limited lifespan. They can typically last at approximately 100,00 miles. Also, like other car components, it wears down over a long period of time. Thus, it is critical to replace them right away when your vehicle driveshaft’s U-joints break or fail.

Conclusion

It is preferable to have a proper U-joint phasing during the installation to the shaft, guaranteeing that the outbound and inbound shafts of the U-joint installation operate at almost constant velocity. Better seek professional advice from the manufacturer and expert mechanic to reduce cost and time.