Typically, lube, oil and filter servicing includes an inspection of the constant-velocity (CV) joint boots. The CV boots keep grease in and contaminants out of the CV joint, whose job is to protect your axle and align your wheels. CV joint lifespan is drastically reduced if the CV boot breaks, so although CV joints tend to last a long time, it’s a good idea to learn how to grease a CV axle when you’re replacing CV boots or joints.
Why to Grease a CV Axle
The typical CV joint boot is made of flexible rubber, which will not last as long as the CV joint it protects. Exposure is the main reason why CV joint boots fail. Oxidation, repeated heating and cooling, and constant flexing can cause the rubber CV joint boot to shrink, embrittle and crack. CV joint boot failure can also be the result of damage brought on by road debris.
Constant-velocity joint boot failure can be a messy problem for the CV joint. First, CV joint grease leaks out, stressing the remaining grease and leading to premature wear. Then, water and other contaminants can enter the joint, accelerating wear.
Whenever a CV boot is replaced, the old grease will need to be removed and new grease added. You’ll also need to grease a CV joint during rebuilding processes, such as replacing an axle stub with a broken wheel speed sensor tone ring or replacing a CV joint.
How to Grease a CV Axle
If you need to grease the CV axle, there are several ways to go about it. Here are a few of the best methods:
- If the Boot Is Shrunken: You’ll need a couple of packets of CV joint grease and a CV boot clamp. Individual or universal CV boot clamps are available for most applications. Stainless-steel zip ties work too. Unbolt the cover or carefully remove the big clamp and pull the boot back. Next, drain or scoop the old grease into a pan. If the joint is dry, remove the axle to clean the joint, and then add new grease and clamp the boot. If the joint is wet, add a packet of grease and install a new clamp.
- If the Boot Is Torn: Get a CV boot kit. You may need a kit that’s specifically for the inner or outer boot if the kit doesn’t include both. Remove the axle, and then disassemble and clean it. If you don’t have a parts washer, then a bucket, some degreaser and a brush can eliminate any grease residue. Next, rinse, air dry and reassemble the components. Add grease before installing the big clamp, and work the joint by hand to distribute the grease.
- If You Need a New CV Joint: A tell-tale clicking indicates that the joint is beyond saving. In this case, you’ll need a new axle or a replacement CV joint. If you don’t have a suitable CV joint on hand, look for a new or remanufactured piece. If your vehicle is rare, new or reman CV parts may not be available. In that case a low-mileage used CV axle may be your only choice. If you’re working with a used CV axle, it might be a good idea to remove the boots to clean the joints and add new grease before installation. Remanufactured CV axles come ready for installation — no CV grease needed.
Timing is critical. If you wait too long to grease the CV joint, it will wear from lack of lubrication or contamination, requiring axle rebuilding or replacement. If you see CV grease all over the wheel well, shock absorber and brakes, but the axle is quiet, greasing the CV axle can prevent more complicated repairs.
Check out all the CV and driveshaft products available on NAPA Online or trust one of our 17,000 NAPA AutoCare locations for routine maintenance and repairs. For more information on how to grease a CV axle, chat with a knowledgeable expert at your local NAPA AUTO PARTS store.
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