Car cv joint

How to identify a faulty CV joint

Unassisted diagnostics of the unit is quite difficult. First, inspect the dust boots. They should be free of any defects, since even 500 kilometers driven with cracked or broken dust boots may often result in damage of the constant velocity joints.

After that, check the free play in the joint by touch. If it is too large, disassemble the unit, or contact a service station for diagnostics at a test bench with the use of special software.

You may notice that the CV joint may need diagnostics by the following symptoms:

• when driving and maneuvering, extraneous sounds are heard from under the bottom of the vehicle;
• deteriorated steerability of the vehicle;
• smoke comes from under the bottom of the vehicle;
• oil stains have appeared on the dust boot.

The reasons of CV joint malfunction

On the average, the service life of the drive shaft joints is 100 to 120 thousand kilometers of mileage. However, components may fail much sooner if the vehicle is operated on poor quality roads, or if the components that are in contact with CV joints have mechanical damage.

Very often, premature failure of the CV joint is due to rupture of the dust boot. Dirt and sand that get inside have abrasive effect on the contacting surfaces, and significantly reduce their service life, while moisture causes corrosion. Besides, loss of tightness in the dust boot is fraught with leakage of the lubricant, which also results in increased abrasion of the CV joint elements.

The service life of the CV joint may also be significantly reduced due to careless driving. Abrupt starts and stops, cornering at high speed, and constant high loads on the vehicle, for example, regular transportation of heavy luggage, lead to the failure of the unit.

Repairing and replacing the CV joint

If you have noticed indirect symptoms of the CV joint fault, or a damaged dust boot is found during routine inspection, the CV joint is to be dismantled, and old grease is to be replaced. Sometimes, to restore a CV joint, it is sufficient to clean it, apply new grease, and replace the dust boot.

In case of a more serious damage, the component is to be replaced. Do the following:

1. Lift the vehicle with a jack, or set it on a car lift.
2. Remove the wheel.
3. Unscrew the CV joint fastener.
4. Dismantle the ball joint.
5. Loosen the hub bolts.
6. Extract the CV joint from the hub, remove the dust boot, and disassemble the unit.
7. Install everything in place in reverse order.