Mazda CV Joints: How They Work and When You Should Replace Them

You’ve probably heard people talking about CV joints, possibly when they were having problems with them. It’s because it’s a common part to fail over time. If you’re wondering if your Mazda is having CV joint problems, or maybe you’re just a little curious about what they do, this guide should clear things up.

What Are CV Joints?

There are two types of CV joints:

  • Ball-Type
  • Tripod-Type

Every front wheel drive car has a CV, or constant velocity, joint on both ends of the driveshafts. The inner CV joints connect the driveshaft to the transmission, and the outer CV joints connect the driveshafts to the wheels. Most rear wheel drive or 4WD cars also have CV joints They are needed to transfer torque from the transmission to the wheels on your Mazda at a constant speed - while also accommodating the up and down motions that go through the suspension. In front wheel drive Mazdas, CV joints deliver torque to the car’s front wheels during turns.

CV Diagram

Problems with CV Joints

CV joints are packed with a special kind of grease, and then sealed with a plastic or rubber boot that’s held in place with two clamps. A CV joint can last a very long time on your Mazda without any maintenance - as long as the protective boot isn’t damaged. It’s not uncommon to see very high milage Mazdas with their original CV joints intact.

The problem with most CV joints is when the plastic or rubber boot becomes damaged or cracks. When this happens, the grease they are packed with begins to leak out, dirt is allowed in, and the result is much quicker wearing CV joints. Eventually, the lack of lubrication and amount of contaminates will cause the CV joint to fail.

Usually, it’s the outer CV joint boots that crack or become damaged - leading to the mentioned problems. This is because they endure the most movement. Checking for cracks and tears is pretty easy, and if the damage was relatively recent, there will be a good amount of fluid/grease coming from the damaged boot.

Signs of a Damaged Boot or Worn Joint

As mentioned, grease coming out of the crack or tear will be evident if the problem is relatively new. If the damage goes beyond a crack or tear, expect to see a dark grease mark or splatter inside the wheel well or inside the wheel itself.

If you keep driving with a damaged CV boot, the joint will evenly wear and fall out. A common sign of an extremely worn outer joint is clunking or popping when turning, or when the weight of the vehicle shifts. The noise will usually get much louder when accelerating through turns. In really bad cases, the outer CV joint can be worn to the point of making your car unsafe to drive.

Failure of inner CV joints is extremely rare. One of the signs of an inner CV joint failure is shuddering or shaking during acceleration. It may also create clunking when shifting from drive to reverse.

Repairing CV Joints

If CV joint damage is caught early enough, repacking the grease and replacing the boot is usually all that’s needed. This is much cheaper than replacing the whole joint and boot — so if you’re lucky enough to catch it in time, address the problem right away. The part isn’t terribly expensive, but there’s a good amount of labor involved with replacement.

Should you discover that the CV joint is worn out, you cannot repair it, it must be replaced with a new part. If you plan on replacing it yourself, you will need a torque wrench, or strong breaker bar, and sockets to break the main CV joint lock-nut loose because it’s extremely tight. Be prepared to have to take the lower ball joint out too and that’s difficult without the right tools.

To summarize, all cars use ball-joints, they will only prematurely fail if there is damage to the protective boot. Check these parts when you change your oil, and you can usually catch the problem soon enough to replace the boot without having to replace the whole joint. Whether you have to replace just the boot, or the whole assembly, be sure to use only genuine Mazda parts to prevent premature wear and failure on the joints and surrounding parts.