If you’re like most people, you probably take for granted the various parts that make up your car and how they all work together to get you where you need to go. One of the most important yet often overlooked parts of a car is the universal joint.
This component is responsible for transmitting power from the engine to the wheels, and if it goes bad, it can cause some serious problems with your entire driveshaft or vehicle’s suspension.
This blog post will cover everything you need to know about universal joints- what they are, where they are used, how much they cost to replace, and how to do it yourself if needed!
Table of Contents
What is a U Joint?
A universal joint, often shortened to u-joint, is a mechanical component that allows two objects (typically shafts or a rear axle) to rotate at different angles while remaining connected. It consists of a pair of hinges with cylindrical cross-sections, known as yokes or trunnions, that are able to rotate within each other.
The yokes are connected by a cross member, typically in the form of a steel shaft, which transmits torque between them. The universal joint allows relative motion between two objects while transmitting torque.
Where You’ll Find a U Joint?
A universal joint is commonly used in drivetrain applications such as automotive and agricultural machinery. The main advantage of the universal joint over other types of mechanical joints is its ability to accommodate angular misalignment between the connected shafts.
This flexibility makes it ideal for use in applications where the alignment of the shafts is not fixed, such as agricultural machinery where the implements being towed may be raised or lowered, or automotive drivetrains where the wheels are able to move up and down as the car goes over bumps in the road.
What is the Purpose of U Joint in Suspension of a Car?
The u-joint, or universal joint, in a car’s suspension system is responsible for connecting the various moving parts of the suspension. This includes the wheels, axles, and driveshaft. The u-joint allows these parts to move independently of each other while still being attached.
This is important for managing the up and down movement of the suspension as well as the side-to-side movement when turning. Without a u-joint, the suspension would not be able to function properly.
What Causes the U Joint Failure?
There are a few different things that can cause a u-joint to fail. The most common ones include:
- Wear & Tear
- No Lubrication
- Heavy-Duty Tasks
- Lifting the Suspension
- Modifications to Vehicle
- Driving Habits
Let us describe these causes in some detail:
1. Wear & Tear:
The most common cause of u-joint failure is simply worn universal joint. Over time, the constant movement of the joints will cause them to wear down, especially if they are not properly lubricated. This can eventually lead to the joints breaking or becoming loose, which can cause all sorts of problems.
2. No Lubrication:
A lack of lubrication can cause premature joint failure in your car. The joints in your car are constantly moving and rubbing against each other, which creates friction. This friction can damage the joints over time, eventually causing them to fail. If the joints are not properly lubricated, they will wear down faster and may eventually fail.
To avoid this, it is important to regularly check the level of lubrication in your car and replenish it as needed. This will help extend the life of your joints and prevent premature failure.
3. Heavy-Duty Tasks:
The premature failure of u-joints is often caused by heavy-duty tasks such as off-roading, towing, or hauling. The constant stress on the u-joints can cause them to wear out prematurely, resulting in a need for a replacement sooner than expected.
If you perform any of these heavy-duty tasks on a regular basis, it’s important to have your u-joints regularly inspected to ensure they are in good working condition. Or install special heavy-duty u joints in your car. You can avoid the inconvenience and expense of premature u-joint failure by doing so.
4. Lifting the Suspension:
If you lift your vehicle’s suspension, it can put additional stress on the u-joints. This is because they are not designed to support the vehicle’s weight when it is lifted off the ground. Lifting the suspension can also cause other problems, such as alignment issues.
While a lifted truck or SUV may look great, the additional height can put a strain on your U-joints. If you decide to raise your vehicle, be sure to have it done by a professional and use quality parts to avoid any problems.
5. Modifications to Vehicle:
One of the most common modifications that can cause premature failure of your U-joints is enhancing your vehicle’s performance by adding a bigger engine. If you have a V8 engine in your car and you decide to upgrade to a larger engine, the weight of the new engine will put additional strain on your U-joints. In addition, the increased power output of the new engine will also contribute to premature wear of your U-joints.
Another modification that can cause premature failure of your U-joints is the addition of larger tires. While bigger tires may give your vehicle a more aggressive look, they can also add unnecessary weight to your vehicle and put additional strain on your U-joints. If you must upgrade to larger tires, be sure to keep the weight of your vehicle in mind and choose tires that are the appropriate size for your vehicle.
6. Driving Habits
Your driving habits can also affect the lifespan of your u-joints. If you frequently drive in off-road conditions or on rough roads, it can put additional stress on the joints and cause them to fail prematurely.
One particular bad habit that can cause u joint failure is riding the brake. When you ride the brake, you are constantly putting pressure on the brake pads, which puts extra wear and tear on u joints. If you must ride the brake, try to do so lightly and avoid doing it for extended periods.
Another bad driving habit that can cause u joint failure is hard acceleration. When you accelerate too hard, you put unnecessary stress on u joints, which can cause them to fail. If you must accelerate quickly, try to do so in a smooth, controlled manner.
So, these were some of the most common causes of u-joint failure. If you keep these things in mind, you can help prevent your u-joints from failing.
Symptoms of a Bad U Joint
If you suspect that your u-joint is going bad, there are a few symptoms that you can look for. These include:
- Squeaking Noise
- Leakage of Transmission Fluid
- Clunking Sound
- Disconnected Drive Shaft
- Vibration
- Vehicle Will Not Move
Let us briefly describe and understand these symptoms in a better way:
1. Squeaking Noise:
When your u-joint starts to fail, you will begin to hear a squeaking noise coming from the joint area. This noise will be most noticeable when you first start your vehicle, and it will go away as you drive.
The main reason behind this squeaking noise is the lack of lubrication in the joint. Now what lack of lubrication does is that it makes the metal components of the joint rub against each other, and that is what you hear as a squeaking noise.
2. Leakage of Transmission Fluid:
Another symptom of a bad u-joint is leakage of transmission fluid. This happens when the transmission output shaft seal in the joint becomes worn out and no longer functions properly. When this happens, transmission fluid will leak out of the joint, and you will notice it on the ground where you park your vehicle.
3. Clunking Sound:
If you notice a clunking sound coming from your vehicle, your u-joint is likely the culprit. The movement of the driveshaft usually causes this sound, and it will be most noticeable when you are shifting gears.
The clunking sound is an indication that the driveshaft assembly is not working properly and needs to be replaced. The main reason behind this little clunk, followed by the ringing sound, is the lack of greasing inside the bearing. Now you cannot do much about the internal lubrication of universal joint bearings, but the external coating of grease might help to prolong its life.
4. Disconnected Drive Shaft:
If you notice that your driveshaft is no longer connected to your rear-wheel-drive cars, your u-joint has likely failed. This can be a very dangerous situation as the drive shaft can come loose and cause serious damage to your vehicle.
A bad universal joint may cause your drive shaft to become disconnected mainly for two reasons. First, the joint may become frozen and no longer be able to rotate. Second, the joint may become so worn out that it can no longer hold the drive shaft in place. Either way, a disconnected driveshaft is a serious problem that needs to be fixed immediately.
5. Vibration:
If you notice a vibration coming from your vehicle, your u-joint is likely the culprit. The movement of the driveshaft usually causes this, and it will be most noticeable when you are driving at high speeds.
The vibration is an indication that the joint is not working properly and needs to be replaced. This vibration is a result of the imbalance created by the failed joint. When one side of the joint is not working properly, it causes the driveshaft to vibrate, which in turn causes the vehicle to vibrate.
6. Vehicle Will Not Move:
A bad universal joint can prevent your car from moving. The universal joint is responsible for connecting the driveshaft to the wheels. If it is damaged, it can prevent the driveshaft from rotating, which will, in turn, prevent the wheels from turning. This can render your car immobile.
How To Replace a Bad U Joint?
While replacing a u-joint is not a difficult task, it does require some patience and attention to detail. Here’s a step-by-step guide on how to replace a bad u-joint in your car.
1. Jack up your car and support it on jack stands. Ensure that the car is securely supported before you begin working on it.
2. Remove the driveshaft. In most cars, the drive shaft is held in place by two bolts at the differential. Remove these bolts and carefully lower the drive shaft.
3. Inspect the u-joints. Four caps hold the u-joint in place. Two of these caps will be loose, while the other two will be tight. The tight caps are what keep the u-joint from moving.
4. Remove the caps. Use a punch or a screwdriver to drive the caps out of the u-joint. Be careful not to damage the caps, as they will be reused.
5. Press out the old u-joint. A press is the best way to remove the old u-joint, but a hammer and punch will do the job if you don’t have access to one. Place the old u-joint on a solid surface and drive out the pins with a punch.
6. Install the new u-joint. Press the new u-joint into place or, if using a hammer and punch, drive the pins into the new u-joint.
7. Install the caps. Drive the caps back into the u-joint using a punch or screwdriver. Make sure that the caps are seated flush with the surface of the u-joint.
8. Reinstall the drive shaft. Carefully raise the driveshaft back into place and bolt it to the differential.
9. Lower the car. Carefully remove the jack stands and lower the car to the ground.
10. Test drive the car. Take the car for a test drive to make sure that the new u-joint is functioning properly. If everything feels good, then you’re done!
U Joint Replacement Cost
The cost of replacing a U-joint in a car will vary depending on the make and model of the car. However, the average cost to replace a U-joint in a car is between $200 and $500. The cost of labor will be the most significant factor in the cost of replacing a U-joint in a car. As this is a long job that requires at least a couple of hours for a skilled mechanic.
However, if you are a beginner attempting to replace it yourself, it may even take a full day or at least 5 to 6 hours. The cost of the parts will also play a role in the final cost. Make sure to get a few estimates from different mechanics before deciding on the final cost.
Conclusion
A bad U-joint can cause several problems with your car from vibrations to prevent your car from moving altogether. A few signs may indicate that your U-joint is going bad. These include vibrations coming from the driveshaft, a clicking noise when turning, and difficulty steering. If you notice any of these symptoms, it is important to have your U-joint checked out by a mechanic as soon as possible.
Frequently Asked Questions
How long can you drive with a bad U joint?
A few miles, not more than that. The U joint is a key component in your car’s drivetrain, and if it fails, your car will not be able to move. A bad U-joint can cause a vibration that will damage the driveline components and eventually lead to complete failure.
Most experts recommend replacing a bad U-joint as soon as possible. Depending on the severity of the problem, some mechanics may be able to temporarily fix a loose or worn U-joint by tightening the bolts or replacing the snaps rings. However, this is only a temporary fix, and the problem will eventually need to be addressed.
How long does it take to replace a bad U joint?
This is a difficult question to answer because it depends on the make and model of your vehicle and the extent of the damage. However, you can expect to spend at least a couple of hours replacing a bad U joint. If you are inexperienced with this type of repair, it may take even longer.
To be safe, it is always best to consult with a professional mechanic before attempting this type of repair on your own.
What is the average lifespan of a U Joint?
The average lifespan of a U Joint is about 100,000 miles. However, this can vary depending on the make and model of the car and driving habits. Rough roads, off-roading, and other factors can shorten the lifespan of a U Joint. Regular maintenance and inspection can help extend the life of a U Joint.
What are the most common types of suspensions in a car?
There are five common types of suspensions in a car:
1. Rigid Axle Suspension: In this type of suspension, the axle is attached to the car’s chassis with either bolts or welding. The main advantage of this type of suspension is that it is very simple and cheap to manufacture. However, the main disadvantages are that it does not provide a very comfortable ride and is not suited for high-speed driving.
2. Multi-Link Suspension: This suspension type is more complex than a rigid axle suspension and uses multiple links to connect the axle to the chassis. The advantage of this design is that it provides a more comfortable ride and is better suited for high-speed driving. However, the main disadvantage is that it is more expensive to manufacture.
3. Macpherson Strut Suspension: MacPherson strut suspension is a type of automobile suspension system that uses the shocks and struts connected to a steering knuckle. It is widely used in modern vehicles and is named after Earle S. MacPherson, who invented and developed the design. This type of suspension is widely used in front-wheel drive vehicles.
4. Double Wishbone Suspension: A double wishbone suspension is a type of vehicle suspension system that uses two (left and right) wishbone-shaped arms to locate the wheel hub.
The main advantage of the double-wishbone suspension over a more conventional MacPherson strut suspension is that it allows for fine-tuning the suspension geometry to optimize several variables. This results in a more accurate wheel alignment and improved handling characteristics.
5. Air Suspension: Air suspension is a type of vehicle suspension that uses air springs instead of conventional metal springs. Air suspension offers several advantages over traditional spring-based suspensions, including a smoother ride, better handling, and improved stability. However, air suspension also has some disadvantages, such as increased maintenance costs and the potential for leaks.
How many U joints are present in the suspension of a car?
Rear-wheel drive vehicles typically have four U joints in their suspension. The front and rear axles are connected to the car’s frame via two U joints each. These U joints allow the axles to move up and down as the car hits bumps in the road while still allowing the wheels to rotate freely.
