Mud Slinger: How To Replace The CV Drive Axle On Your Subaru WRX

To remedy our subject car’s leaky stock CV joints, we ordered a pair of Cardone Select CV drive axles through Summit Racing Equipment. Part number AAZ-66-7259 is an exact-fit replacement.

The first step is to disconnect the car battery and then get the car safely in the air. While we had the luxury of using a two-post lift, jack stands will work just fine. Remove the wheel next. As a side note, if this is your first time, do one side at a time in case you can’t figure out how things go back together—this is a fairly simple and straightforward install though.

. Next, you’ll need to remove the retaining nut atthe center of the brake disc. As you can see from the picture, the top of the nut is made to be crushed into the retainer slot. You can open this a bit with the tool of your choice, but most impact guns will zip the nut off with no problem, and the new axle comes with a new nut. Many cars and manufacturers utilize different fasteners for drive axle retention, with some requiring odd sized sockets or cap screws, so research your vehicle in advance.

You need to separate the lower ball joint from the control arm next. Remove the cotter pin and then loosen the nut, but leave it threaded on the stud a few threads. If these have never been off the car before, or you live in a snowy climate, you may have to break the ends of the cotter pin off and then drill out the remains like we did. Start with a very small drill bit and once you’re through the stud, you may be able to push the leftovers out with an awl or similar implement.

You can rent a ball joint removal tool, or do it like we did—with the suspension at full droop, use a large hammer and hit the control arm near the ball joint. With the WRX having boxed control arms made from stamped steel, striking the arm doesn’t have the same intensity that hitting a solid one does, but it works. You’ll want to make sure they are not overly rusty as you could further fatigue the metal, and you want to be careful not to hit the ball joint boot as well. Striking the control arm should separate it, but if it doesn’t, use a jack to lift up on the ball joint stud and keep pressure on it while you continue to strike the control arm. Don’t use the hammer technique if your particular vehicle has aluminum control arms.

While we recommend getting an alignment after this procedure, you’ll want to keep the suspension settings as close to normal to get you to the alignment shop. Mark the upper and lower bolts across the bolt and onto the strut and be sure to line these marking up during reassembly.

The strut fasteners are different lengths, so be sure to remember where each one goes. Once these are removed, you can lift the spindle assembly out of the control arm.

Unbolt the brake line bracket from the strut.

Before going any further, you’ll want to ready some sort of hanging implement as you’ll need to suspend the spindle assembly during the axle swap. A bungee cord will work, but something less flexible will ensure that the spindle stays out of the way. We used simple brake caliper hooks, similar to the OTC Caliper Hanger set (PN OTC-7661) available through Summit Racing. Since we are discarding the old CV axles, it’s ok to use a hammer to tap the axle back through the spindle hub. Once you’ve got it on the move, most CV axles are easily pulled out the backside.

Pick up the spindle assembly, pull it out and turn it towards the front of the car. As you are doing this, push the CV axle inward and flex the joint as needed to remove it from the backside of the spindle. Now hang the spindle assembly up and out of the way.

Here, you can see that the CV boots have broken open and have slung the internal grease all over. Once you have the axles removed, take the time to clean the mess up, as this will make it easier on you should other maintenance or modifications require you to dive back in and under your car. Also notice the grease all over the factory downpipe. This can make your car a bit stinky, and it can ruin the finish of aftermarket pipes as well.

Different manufacturers and car models have different ways of securing the CV axle to the transmission. For many Hondas, it’s a simple snap ring and you only need a pry bar to pop this end of the axle loose. For VWs and Audis, cap screws around the perimeter are employed. This WRX, and most Subarus, utilize a simple roll pin. Use a roll pin punch to drive the pins out, and then slide the axle off of the splined transmission shaft.

Break out that new Cardone Select CV axle and slide it into position. Be sure to note where the roll pin hole is on the transmission shaft and the CV axle, and line them up as you’re sliding it on. If you meet resistance when tapping the pin in, you may have to rotate the CV axle 180 degrees to get the roll pin holes to line up properly.

We preferred the factory Subaru roll pins over the included new ones from a design standpoint, but as you can see, the new ones are longer and will be needed to properly lock the axles onto the transmission shafts.

Now reassemble the suspension components in reverse order and be sure to check all of your fasteners. The final one, the axle retention nut, must be torqued to 137 ft-lbs. If all you have is hand tools, you may need to pop the center cap to your wheels, mount said wheels, and set the car on the ground to apply the torque wrench. Most quality impact guns exert greater than 137 ft-lbs of torque, though, if you choose to go that route. With our new CV drive axles installed, we can look forward to many more care-free miles on our WRX. As we continue this build series, we’ll be installing a cold air kit and a turbo-back exhaust next. See you then.