How do you replace the outer CV boots on a 1999 Hyndai Elantra?

You must first make sure the CV JOINT IS NOT COMPROMISED! Otherwise, you might as well buy a re-manufactured axle for $50+ dollars. In addition, you can buy a boot that fits around the axle without taking everything apart, but it is not as good as OEM stuff. I would first take off the wheel, turn the wheel all the way to the left or right and feel the boot to make sure it is bad. You will here air noises and boot will feel empty. If this is the case, then you need to take the tie rod and ball joint off to swing out the axle.

WARNING!! Ball joint is pressed in and very difficult to remove. You might want to pay someone to do this part. A special tool can be used to loosen ball joint, and another press tool can help with removal. You can completely remove the steering knuckle as well if you unbolt from strut. This would be a good time to replace wheel bearings by taking the steering knuckle and hub to a shop off the car. They should discount the fee heavily for you having taken it off the car. Another special tool is required for wheel bearing replacement and the Harbor Freight version of this tool probably will break and not work.

Now, you simply cut off the old boot, wipe away all the grease, clean with a degreaser, and put the new grease in the boot and some on the joint. Now, slide the boot over joint, tighten the clamps to specification making sure boot is at proper length according to manual.

Re-assemble everything.