The modern and most frequent and successful version of the cv joint, with a ball and cage, was invented in 1928 by Alfred Hans Rzeppa. For this reason the cv joint was also known as the Rzeppa joint . An engineer for ford, he did not invent the entire concept, but he did invent the most common version and most successful. The Rzeppa joints or cv joints usually have six balls, however there are versions with three balls as well.
The modern CV joint explained
The CV Joint is part of the constant velocity axle where it can be found on both the side of the gearbox as well as the wheel side. It is protected by a special encasing or slipcover protecting it from dirt and moisture. When you are in doubt as to whether your CV joint is still in perfect working condition there are several ways to check that out. First of all, when your CV axle is showing some leeway you will notice it sooner or later. The cause of it is usually space in between the universal/cross joints. These universal joints are there to absorb the motion of both the horizontal axis and the movement of the vertical axis. If you have a car with rear-wheel drive it is easy to determine whether or not the CV joint is giving out. What you do is you grab hold of the constant velocity joint with your hands, on both the left and the right side of the universal joint and by making a rotating motion you will be able to feel the leeway. If it is too difficult try removing the constant velocity joint first.
Early warning to a bad CV joint
The first obvious sign of a bad cv joint is clicking noise. The noise is usually a thumping or clicking one. What happens when a cv joint wears off is that the rubber degrades. When this happens the clamps on either side of the rubber lose their tension as the rubber degrades further. This causes you to lose lubricant or grease when the axle spins. You get the effect of what happens similar to when you swing a bucket around in a circle. The water gets pushed to the back of the bucket and thus you are able to swing the bucket upside down without the water falling out. This is caused by the centrifugal force that pushes the water to the outer side of the bucket. This outer side is of course the bottom of the bucket. The same effect can be seen when the rubber starts degrading. Cracks show, tension loosens and through the centrifugal force the grease is slowly pushed outwards. Wearing and tearing even faster.
Another way of finding out if the CV joint noise is actually what you think it is, a worn CV joint, is by listening when driving at high speeds. The noise, and an often occurring vibration should be felt and heard when you accelerate. Take your foot off the gas and the vibration should stop or lessen. This rules out any form of tire imbalance issues and pinpoints it on the driveline. If you have a CV joint in your hands, try shaking it to hear any strange noises. It should not make sounds except for the obvious.
The composition of a CV joint
A CV joint, short for constant-velocity joint, is made up of an outer cup that is connected to the axle trunnion on the wheel side or the inner side plus an inner framework that is attached to the axle. On both ends you will find ball tracks where in the balls are able to roll. The balls are contained in a ball cage. The balls are lubricated with graphitized grease which is contained by the CV cover.
How to remove CV axles
Replacing constant velocity axles is a lot easier when doing it to a rear-wheel drive. A front-wheel driven car makes it a lot harder. Note, a front wheel driven car also puts a lot more strain on the constant velocity joint. When you have a front-wheel driven car, removing the cv-joint or constant velocity axle includes a lot more work. It will be possible that you will have to remove a part of the suspension first. After the car has been jacked up and the front wheel(s) have been removed you can commence unscrewing the suspension. If the locknut on the end of the disc brake has been unscrewed and removed and the king pins and rod ends have been removed, the hub where the disc brake has been attached to, may be removed. To be able to reach the constant velocity axle properly it would be wise to sometimes remove the entire strut. In other cases though, just removing the hub will be more than sufficient.
Not sure what is going on inside your car?
Call in an expert to diagnose your vehicle. An expert can help you give proper advice and usually find the problem much faster than a person can do himself. The benefits of going to an expert is that you will be able to prevent high costs that would otherwise be incurred. By going in soon and getting it checked out, you could keep a small issue small, instead of it deteriorating further. This can cause further damage and even end up causing potentially dangerous situations. When consulting an expert you can always ask what the costs are of the diagnosis and to not do immediate repairs without first consulting with you about the costs. If the problem is quick to be found an expert can almost always give you an estimated cost for the repairs. Note that it is usually split between labor costs and material costs, depending on what needs to be replaced or just repaired costs can vary greatly. So prevent high repair and replacement costs, and keep you and others around you safe on the roads. Let an expert check it out for you.