Today changing CV (constant speed) axles is almost as common as doing brake work. But some CV axles can be quite difficult to remove. In this article, learn some of the tricks I’ve used over the years as a Master Tech to make shifting CV and 1/2 axles easier. Sometimes specialized automotive tools are needed to make the job easier, I will discuss some of them and whether it is better to replace the entire axle shaft, gasket, or just the CV boot.

Clicking Turns

Since you are reading this, you may already know that a common sign of a bad CV joint is popping and clicking turns. A chill on straight take-offs could be a worn internal joint, but this is much less common. The outer joints are the ones with the most movement (such as in turns), which is why outer boots tend to carry more than inner ones. CV boots are designed to pump fat throughout the joint during movement. The wear that makes the outer seals noisy can be accelerated if the CV boot is broken by dry rot or wear and the lubricating grease is lost. If the CV trunk breaks, the grease comes out of the gasket by centrifugal force while driving. With no grease to keep the joint lubricated and cooler, its life is drastically reduced. In addition, external elements such as moisture and dirt can enter the gasket, further reducing its service life. Once they wear out, they make a clicking noise when turning as they accelerate. If they are noisy, the 1/2 shaft assembly may be the easiest way to go rather than just replacing the gasket. 1/2 CV axle prices have dropped in the last decade and are more available than ever.

Removing the half shaft assembly

The job of removing axle shafts on most cars is pretty much the same.

1. Remove the large nut that secures the link to the wheel hub.
2. It may be necessary to unscrew or unhook the brake hose to prevent it from stretching when removing the axle.
3. The steering knuckle (where the brake rotor is mounted) must be loosened at the strut mount or lower ball joint to allow the axle to slide out of the hub. Choose the easiest!
4. The internal CV will be attached to the transmission by bolts or a retaining clip (clip not visible).
5. If there are no bolts in the inner gasket, in most cases it will be necessary to pry with a pry bar.
6. Alternatively, a slide hammer with a CV joint puller can be used to remove the inner joint from the transmission.

Boot inspection and replacement

You may be able to detect and replace worn boots before CV joint damage occurs. If the boot has dry rot and is about to crack or has recently split. And the CV joint still doesn’t make any noise, you caught it in time. The CV axle shaft assembly can be removed and of course only the boot can be replaced with new grease. The CV starter kit also comes with two clamps and special grease. It is less expensive to restart a joint, but requires a little more labor. On cars that I was familiar with, many times I changed the CV boot without completely removing the axle from the car. However, the axle is usually removed and placed for the purpose of work. The old boot is cut away to help reveal what type of retaining clip holds the gasket on the 1/2 shaft.

When using a cleaner, such as clean brake and the joint is at an angle, it is easier to see the clip. The joint may need to be rotated while held at an angle to view the clip. Most require lock ring pliers to extend the lock ring or the joint can be struck hard with a hammer (care must be taken not to damage the cage). If in doubt about the type of retainer you are working with, consult a service manual for your specific model. Note that ball bearings can fall out when the gasket is off the shaft and the cage is turned sideways, depending on the type. After cleaning and drying with compressed air, the grease bag can be cut at the corner and the grease is squeezed out in the middle of the joint. It is common to expel some of the old fat that was trapped by doing this. Collect and discard any old grease that may leak. Replace the boot and gasket on the shaft by extending the clip or tapping with a brass hammer. Special CV joint boot clamp tools will be needed to tighten the bands properly. There are two basic types of clamps. There is a type that is crimped with boot clamp pliers. The other type requires a banding tool, this type rolls up and tightens with the same motion as you would with a can opener.

A common mistake is damaging the output seal in the transmission when removing or reinstalling the shaft. Damaged seal will cause transmission fluid leak. Take care to center the inner gasket when replacing it. Also a mistake even professionals make is breaking the cir-clip that holds the shaft in the transmission or not installing the shaft completely INSIDE. It is normal to feel a little inward and outward movement when pushing and pulling the inner gasket when properly installed. If the retaining clip is broken or not fully inserted, the axle can slide far enough that the car won’t move. Also, if you hit the shaft again in the transmission, be careful not to damage the outer threads. Remember, if this is your first axle job, feel free to have an experienced friend on duty!