What are CV Axles and what do you need to know about CV Axles Repair? CV (Constant Delivery) axles are a type of drivetrain component that can be found on a wide range of modern vehicles. They pass power from the vehicle's transmission and differential to the wheels, which allows the vehicle to move forward.
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They have a greased flexible joint that allows the axle to flex in response to road conditions while still delivering strength. Since the wheels in an IFS 4WD (Independent Front Suspension 4-wheel drive) turn and go up and down, the CV joint must be able to turn with the wheel as well as go up and down.
The CV joint in a solid-axle application just needs to shift side to side when rotating the wheel. So, although they can appear to be different, they all serve the same purpose: to provide power to your front wheels.
The CV’s joint is lubricated with grease and protected from dirt and debris by a rubber boot. Since the CV axles are the direct connection that transfers engine power to the wheels, they are subjected to high levels of stress over time and will gradually wear out, necessitating CV axles repair or replacement in order to restore proper functionality. As CV axles wear out, they normally generate a few signs that warn the driver that they need to be fixed.
CV Axles Repair: Why do CV joints break?
A CV boot may be ripped or broken without anyone noticing. Dirt and moisture can get into the joint, causing excessive wear, binding, corrosion, and premature failure. Sudden failures of CV joints are rare, but when they do it could be as a result of the loss of lubrication or grease contamination (commonly because of a failed boot).
Another main cause is shock loading, which happens when a spinning wheel lifts off the ground and then lands hard. This can happen very often with an individual suspension system due to the typically small amount of movement.
Shock loading puts tremendous strain on the driveline, with CV joints usually being the weakest connection. The CV joint cage will physically break, and in some situations, the individual shaft will shear, although this is rare. When a 4WD starts to bounce or hop while climbing an obstacle, this is the type of condition that will cause a CV joint to fail.
CV Axles Repair: Failing CV Axles Symptoms
CV Axles that are failing usually produces various symptoms:
- Knocking Sounds When Moving
A CV joint that has been worn out due to repeated usage can create a knocking noise. On a front-wheel-drive vehicle, the noise may be coming from the inner joint.
It may come from either the outer or inner joints in the rear-wheel drive. The differential gears can also make knocking noises.
Put the vehicle in reverse and accelerate, then decelerate to conduct a self-diagnosis of the joint problem. Switch between acceleration and deceleration, and keep an ear out for louder knocking noises as this can be evidence of a faulty CV joint.
- Loud clicking or popping noises when you turn
An audible clicking noise when turning is one of the most common and visible symptoms you need CV axles repair. They become loose and click when turning. During sharper and faster turns, the clicks can become louder or more pronounced, and they can be heard on the side with the defective CV shaft.
This symptom almost always means the outer CV joint is worn or weakened. Put the car in reverse, turn the steering wheel to one side, and push the vehicle backward in a circle (first check the rearview mirror!). If the noise becomes louder, the diagnosis is confirmed, and a new joint or shaft assembly is required.
- Grease on tire edge
Grease on the inside edge of the tire or along the underside of the vehicle is another sign of a CV axle shaft issue. A broken boot leaking grease, which is thrown around as the axle spins, is typically the cause. Since dirt and debris will get into the boot and damage the joint, a leaky boot will eventually lead to CV joint failure. Darker-colored grease can be evident on the rim and wheel's interior if the CV joint is badly damaged. If you see grease splattering, it's possible that the axle has been tainted or has been damaged due to a lack of lubricant for a prolonged period of time.
- Excessive vibration as you drive
Excessive movements or vibrations from the axle when driving are another sign of a failing CV axle. When a CV joint or axle shaft is damaged in some way that affects its balance while moving, the shaft can vibrate excessively when the vehicle is being driven.
As the vehicle speed increases, the vibrations can oscillate or become more pronounced. Excessive vibration caused by failing CV shafts can affect the vehicle's handling and ride characteristics, as well as its overall protection and comfort. If the CV axle is damaged enough to cause vibrations, it will normally need to be replaced.
AS CV axles are the final link between the engine and the wheels they are an important function of transferring power from the drivetrain to the vehicle's wheels for it to move forward. As a result, if you believe that one or more of your CV axle shafts is malfunctioning, you can investigate further.
This symptom is rarely caused by a failing CV joint or by FWD half shaft imbalance. The most common causes are an unbalanced tire or wheel, an out-of-round tire or wheel, or a bent rim.
- Bouncy Driving
If you're driving on a flat paved road and your car is still jumping around, you most likely have a defective CV joint. You should double-check this by visiting a transmission repair store. Switch between acceleration and deceleration, and keep an ear out for louder knocking noises. This is evidence of a faulty CV joint and that you already need CV axles repair.
This symptom is caused by worn or damaged wheel bearings, a bad intermediate shaft bearing on equal length half shaft transaxles, or worn shaft bearings inside the transmission, and is often due to insufficient lubrication in either the inner or outer CV joint.
- Binding
In the worst-case scenario, the joint will not allow any movement at all. You can encounter pause, on top of hearing loud clunking as you accelerate. Significant juddering can jeopardize handling and safety, particularly while traveling at highway speeds.
The clamps on the axle shaft cinching the outer CV joint’s boot becoming loose could be caused by a torn boot due also because of the lost grease. You will be able to prevent damage to the joint if you notice the issue early.
Since modern CV joints cannot be disassembled or rebuilt, the only option is to replace the entire shaft. Even if just one axle shaft is faulty, I've heard that you should repair both axle shafts.
It's the same big mechanical job if you're removing the shaft to repack the joint with grease or replace it. The wheel hub nut must be removed with an impact wrench or a long breaker bar. There's also the arduous task of disassembling and reassembling suspension and steering parts. So, even though labor costs were comparable, I still saved money because I just purchased boot clamps and grease instead of a new axle shaft.
CV Axles Repair Cost
A CV joint will cost anywhere from $95 to $210. It would cost between $165 and $800 to hire a mechanic to perform the replacement. Whether you're replacing a double or single axle determines the price. A double axle's constant-velocity joint replacement would cost about twice as much as a single axle, with parts costing between $150 and $400 for a double axle.
The average cost of hiring a mechanic to perform the replacement varies from $230 to $1180. Another consideration is the make and model of your car, as well as the difficulty of the replacement work. Obviously, the more time they take, the more costly the service becomes.
Since this is a major operation, the car technician or mechanic can also perform a general safety check, paying special attention to the boots and axles. There could be a leak from the CV boots if the tires have grease on them. Additionally, any loud grinding noises you hear when you turn indicate that the axle can need to be replaced.
CV Axles Repair: Frequently Asked Questions
Can you drive with a broken CV axle?
A straight answer is yes, for about five months. You can extend that by a month or two. However, you have to take your car to a mechanic by the end of your sixth month to get the defective component replaced. Anything more than six months tops isn't a good idea for you or your vehicle.
The six-month period is also for those who live in a dry climate with no rain, dirt, or even snow. And since there aren't many places that have such a nice climate all year, so the six months might already be a stretch for you.
If you live in an area where there is a lot of snow or rain, or even both then you really shouldn’t wait six months before you do the CV axles repair. To be on the safe side, after 3 months in, you should do the CV axles repair or it will sustain more damage being exposed to the rain and snow.
This is especially true if the CV axle has been damaged by a leaking boot. More dirt would get inside it, and things would slowly worsen with time, which is obviously not healthy.
What Will Happen If You Keep Driving On A Bad CV Axle?
When you keep driving your car on a poor CV axle, the most serious issue you'll face is that it will eventually stop moving. Even though this will appear to be an unlikely problem that will never happen to you the truth remains that it has happened to many people in the past. As a result, don't take it lightly.
What happens is that the joint is unable to properly perform its function, which is to shift power from the engine to the wheels. The car becomes immobile as a result of this. The car may not shift in this situation, but everything else will be moving, which will cause damage to the car's suspension.
The main issue is that the car will unexpectedly stop moving, and you have no control over it. Imagine the horror of it happening in the midst of heavy traffic, or it could happen in the middle of nowhere with no one around to assist you. So, to be safe and sure you are not going to be in such situations, it is far better to do the CV axles repair when you start detecting the symptoms mentioned earlier.
How long does it take to replace a CV axle?
Replacing a CV axle will take about an hour. It is estimated that replacing one axle, whether it is the rear axle or the front axle, would take around one hour if done by a competent mechanic.
Can a bad CV axle damage transmission?
Yes, a bad CV axle can cause your transmission to go bad as it causes transmission leaks due to a damaged seal. If you can grab the axle closest to the inner joint near the transmission and you are able to move it up and down then that is a sign the differential in the transmission is worn.
Do I need to replace both CV axles?
Although CV joints and boots can be replaced individually, most experienced technicians and even do-it-yourselfers tend to replace the entire half shaft assembly with a remanufactured shaft. It's always a good idea to patch both shafts at the same time on a high-mileage vehicle with a poor CV joint or boot.
Conclusion
CV axles are a critical component that keeps your vehicle moving. So it is recommended that a drivetrain inspection be made a regular part of anyone’s vehicle maintenance routine. During this maintenance inspection, the technician will be inspecting the vehicle’s CV axle half shafts, joints, and boots, universal joints as well as other critical steering and suspension components.
If you are already observing the symptoms mentioned above, best to do the CV axles repair as soon as possible if you do not want to be stuck with an undrivable vehicle in the middle of the traffic or in the middle of nowhere.