Found on anything from four wheelers to one-ton 4×4’s, constant velocity (CV) joints are handy devices that facilitate power transfer from the drive train (differential) to the wheel (via the hub) in independent suspension applications. Unlike the universal joints typically found on drive shafts, CV joints can operate at relatively extreme angles without vibrations or variations in output speeds. Although CV joints aren’t directly related to suspension components, they’re often in the way when doing things like installing lift kits. Therefore, it’s a good idea to have an understanding of their ins and outs before tearing into anything.
First off, you never want to over-extend a CV joint in any direction. Granted, every joint is different in terms of extension limits, but as a general rule, don’t flex or extend it until it stops. The guts of the joint consist of large ball bearings riding in tightly machined races. If anything in there ends up misaligned or chipped, the joint will bind, make noise, and/or fail catastrophically. If, for example, you are able to wiggle your strut (or whatever) out without disconnecting the CV shaft, make sure that the hub assembly is secured out of the way with a bungee cord or a piece of cable such that the CV joints are not hyper-extended.
If you do have to disconnect the outer end of the CV shaft from the wheel hub, you might find that the splined section doesn’t want to come dislodged from the wheel bearing assembly, especially if the vehicle has spent any amount of time in the Snow Belt during winter. The typical reaction here is to find the nearest dead blow hammer and aggressively strike the splined end with the axle nut partially installed, so as not to damage the threads. Do NOT, under any circumstances, do this. Every strike of that hammer sends a shock wave up the driveline, risking damage to the wheel bearing, either CV joint, and/or (and you REALLY want to avoid this) the bearings in the differential. What you do instead is drop the brake caliper (secure it out of the way) and rotor and force the joint splines out with a large universal puller. Doing it this way applies a steady force to specific point and mitigates the risk of breaking a bunch of other stuff in the process. Remember that if you’re only going to disconnect the outer end, you’ll need to secure that CV shaft so that the joints aren’t over extended.
If you wish to remove the CV shaft completely, you’ll need to take some precautions when disconnecting the inner CV joint. Some vehicles’ inner joints are bolted to a flange and are fairly straight forward to disassemble. Others, however, have a splined fitting, similar to the outer joint and are held in place with an internal c-clip. Do not attempt to dislodge an inner CV joint by tugging on the axle shaft as you will likely do some damage to the internals of the joint. It’s much safer and easier to pop the joint loose by inserting a pry bar between the CV joint housing and the differential housing, taking care not to damage either housing. When removing or installing the inner joint, make sure to only grab it by the CV joint housing and not the shaft.
While everything is apart, carefully inspect both CV joints for things like proper lubrication and cracks in the rubber boots. If anything is out of sorts, replace it now. When re-installing an inner joint of the splined and clipped nature, make sure you only apply pressure to the joint housing. The c-clip can be a little fussy to align but if you check out this excellent column, you can find some tips on lining up that clip. Once everything is back together and the vehicle is still in the air, pop it into neutral and make sure that the wheels can spin without binding up anything in the driveline. Check the manufacturer’s torque spec on the outer axle nut as it can vary drastically between vehicle models and years. From there, you should be good to go without any driveline worries.