Use the weight of the car to hold the axle while you loosen the axle nut
Performance Gain:
Smoother drivetrain
Complementary Modification:
Replace your rear wheel bearings
This article is one in a series that have been released in conjunction with Wayne's new book, 101 Performance Projects for Your Porsche Boxster. The book contains 312 pages of full color projects detailing everything from performance mods to changing your brake pads. With more than 950+ full-color glossy photos accompanying extensive step-by-step procedures, this book is required reading in any Boxster owner's collection. The book is currently available and in stock now. See The Official Book Website for more details.
Check out some other sample projects from the book:
One of the most common suspension items to replace or service on the Boxster is the constant velocity, or CV joints that connect the wheels to the transmission. These bearings, packed in grease, experience a tremendous amount of use throughout the years, and thus have a tendency to wear out after about 100,000 miles or so. One of the clear signs that the joints need replacing is the distinct sound of a clunk, clunk, clunk coming from the rear axle when the car is in motion.
In some cases, the boots that cover and protect the CV joints will be torn and need replacing. The procedure for replacing the boots is very similar to the procedure for replacing the entire joint. New boots should be installed each time a CV joint is replaced.
For the Boxster, Porsche sells only the inner CV joints, or a complete, replaceable axle. The new axle contains both the inner and outer CV joints, as well as the boots that cover and protect them. Although the inner Boxster CV joints are available separately, I typically recommend installing the complete axle. All you need to do is to bolt it up to the car, and you don't have to mess with disassembly or CV joint grease.
If you are going to be replacing the entire axle, then you first need to loosen up the big axle nut. With the car on the ground, in gear, and the emergency brake on, remove the center hub cap (see Photo 3 of Pelican Technical Article: Tire and Wheel Sizing), and use a long breaker bar to loosen up the drive shaft flange axle nut. This nut is tightened to more than 460 Nm (340 ft-lbs): it will take quite a bit of force to loosen it up. Lift the car up again and remove the wheel once more. If you are going to be replacing the inner CV joint only, then you can leave this nut alone.
The next step in replacement of boots, joints or the axle is to jack up and raise the car off of the ground and remove the road wheels (see Pelican Technical Article: Jacking Up and Lifting the Boxster on Jack Stands). Then, remove the diagonal braces and the aluminum transmission cover (see Pelican Technical Article: Changing Automatic Transmission Fluid). Now remove the bolts from the inner CV joint using an hex socket (see Figure 2). In order to gain access to the CV bolts, rotate the wheel of the car until you can clearly get your hex socket on the bolts. Then, pull the emergency brake and place the transmission into first gear. This will allow you to loosen the bolts without having the axle spin. When you have removed all the bolts that you can from this angle, release the brake, take the car out of gear, and rotate the wheel until you can reach the next set of bolts. When all of the bolts are removed, suspend the end of the drive axle with some rope or wire.
With the CV joint disconnected from the transmission, you can work on replacing either one of the CV boots, or the inner CV joint. If you're replacing the entire axle, then you can skip these steps, as the axles come complete with new joints and boots. Remove the six bolts and the half-moon washers from the joint and pry off the dust cap (blue arrow, Figure 2). Then remove the circlip that holds the CV joint onto the axle (Figure 3). Cut or disconnect the clamp that holds the boot to the shaft, and the old CV and boot should simply slide off of the shaft. In general, it's a really bad sign if large balls from the bearing start falling out. That's a clear indicator that you need to replace the joint. If you are reusing the joint again, make sure that you carefully place it in a plastic bag, and avoid getting any dirt or grime in it. Even a crystal of sand or two accidentally placed in the CV joint can help it wear out prematurely. Inspect both CV joints for any wear prior to installing them back into the car. If you are simply replacing the boots, then carefully pry the old boot off of the joint. It is pressed onto to the end of the joint in a similar manner as the dust boot.
With the inner CV joint and boot completely removed, then your axle should resemble the inset of Figure 4. If you are replacing the boot on the outer joint, undo the clamp, and remove the boot and cover. Replacement boots aren't typically sold with the metal mounting plate attached, so you'll have to pull the old boot off of the plate and transfer the new one to it. Reinstall using a new pinch clamp, but don't tighten it quite yet. Reassemble your old CV or a new one onto the axle. With the new boot attached, rotate the joint through its entire motion before tightening the small, inner boot clamp: you don't want it to be too tight.
Whether you're reinstalling your old CV or using a new one, I recommend repacking the joint with grease. Also make sure that you place plenty of grease in and around the boot. Move the joint in and out as you insert the grease to make sure that you get it well lubricated, as the new CV joints do not come pre-greased. My preferred choice of lube is Swepco 101: a $12 tube should be good for about four joints total. When reinstalling the bolts into the transmission flange, make sure that the bolt threads are free of grease. Any grease on the threads can cause the bolts to come loose, and create a dangerous situation. Also, all your CV bolts should be checked after about 500 miles of driving.
If you are replacing the entire axle, then there are two different methods you can use. You can remove the entire wheel bearing carrier, (detailed in Pelican Technical Article: Wheel Bearing Replacement), or you can simply slide the axle out of the hub if you have enough clearance. Very often, the axle will get stuck in the wheel hub due to corrosion or rust: it may need some encouragement with a big hammer to be removed. You will need to remove the exhaust and the rear sway bar once you have the axle nut removed in order to gain enough clearance to drop the axle down (see Figure 6).
Once you have the entire assembly back together, take the car out for a drive, and check the rear for noises. All should be smooth and quiet, and the boots should no longer leak.
Figure 1
Shown here is an inner CV joint replacement kit. The kit comes complete with the joint, the boot, a new boot clamp, new bolts, a new circlip, and enough CV joint grease to lubricate the joint. If you are planning to remove the whole axle, be sure to order a replacement axle nut as well (shown in photo). On the Boxster, the outer CV joint is not available separately, but must be purchased as part of a complete axle. This is because the joint is integrated into the stub axle and cannot be separated. If the boots are damaged and leaking, then you should replace them, because dirt and debris can find their way inside.
This photo shows the process of disconnecting the inner CV joint from the transmission. Use a really long extension and a hex socket tool to easily remove each of the six bolts that secure the joint to the transmission (inset). With the joint disconnected, remove the bolts and the half-moon washers. There is a dust cap (blue arrow) that protects the CV joint. Carefully pry this dust cap off to access the circlip underneath.
The CV joint is held onto the axle by a circlip, which is very difficult to see in this photo. The two orange arrows point to the ends of the circlip that must be removed by using a set of special circlip pliers designed specifically for the task (inset).
The four CV joints are located in the rear of the car, attached to both the transmission flanges and the stub axles on the trailing arms. I recommend that you replace the joints in pairs: either both of the inside ones or both of the axles. Chances are if one of the joints is showing signs of wear and deterioration, then the other three will not be far behind. This photo shows the new CV joint installed with a new boot and boot clamp (purple arrow). The inset photo shows the axle with the boot and CV removed. You need to remove everything off of the inside end of the axle as shown, in order to slide on new boots for both the inner and outer joints.
If you are replacing the entire axle, then you need to remove the outer axle nut (yellow arrow). This is best done with the car on the ground by placing a long breaker bar on the nut while the wheel holds it steady. Pry off the small inner hubcap to gain access to this nut while the wheel is still on the car (see Photo 3 of Pelican Technical Article: Tire and Wheel Sizing).
There are two methods you can use to remove the axle from the car. You can remove the wheel bearing carrier as detailed in Pelican Technical Article: Wheel Bearing Replacement, or you can drop down the rear sway bar and exhaust to gain enough clearance to remove the axle. Unless I'm planning on doing some major work on the brake calipers or the wheel bearing, I typically prefer to drop down the exhaust to gain enough clearance. As you can see in this photo, the exhaust pipe (blue arrow) is getting in the way of dropping down the axle (red arrow). The axle flange on the transmission is shown by the orange arrow.
Comments: Before I start with a cracked inner CV boot replacement, is there any lock tight needed on the CV joint bolts? Also, is there a special axle boot clamp tool needed to tighten the clamps?
April 6, 2012
bala
Comments: Just an FYI to folks doing the regreasing of the CV. One tube of the 100 is not sufficient. Unless the method is to only coat and not pack the grase in. The article and the book don't explain how much. 1 for each end is what I can estimate based on what I have read.
March 2, 2012
Patrick
Comments: Have read the article a few times before I embark on changing the CV boots. I get the idea of dropping it at the transmission end having removed the sway bar and the exhaust, and I can see how with removal of the inner CV joint you can work backwards towards the outer one.
Why cant you use this method to remove the whole shaft from the vehicle by removing the axle nut tight! and pushing the whole shaft inwards under the gearbox. Seems this would avoid any messing with the various hub links risking putting your geometry out. And even if only for the boot change would allow an easier job by being able to get it on the bench. What have I missed?
February 21, 2012
JS
Comments: In this case, my experience is similar to ST.
The inner CV didn't come off without encouragement. I tapped at the back of the CV only the piece right around the axle-with a long drift and 5lb hammer.
I had decided to pull the whole axle to make the removal of the inner CV easier on the work bench. Unfortunately, the axle was unwilling to come free of the hub. I didn't want to get to heavy handed with the hammer and wood blocks were splitting - elected to tap the back of the CV instead.
I did remove the exhaust and lowered the sway bar, I would recommend this even for only replacing the inner boot, it seems to make the job easier because of the better access.
Thanks for all of the tech articles.
January 29, 2012
ST
Comments: Just as a followup for other DIY'ers, I completed this project, but it was quite involved. The CV's did not come off easily. I had to heat them with a heat gun and used a 5lb hammer to pop them out. To install the new CV's I had to heat the CV and user a 22mm socket as a pivot to hammer the new CV's in. Heating made all the difference....
Ensure that you have all the boots and lids in place before installing the new CV as I destroyed a CV trying to take it out because I forgot to install the inner boot.
January 28, 2012
ST
Comments: Hello Wayne:
I am tackling this project right now. You said the CV joint will slide off after removing the circlip. I find that it is a lot harder than that. I am afraid to hammer hard as I might damage the outer joint that is still attached to the wheel carrier. Any recommendations?
December 28, 2011
Followup from the Pelican Staff: I would carefully tap on the inside flange to help release the bearing if it's stuck. A few taps on the inner race with a small plastic hammer may give you just the force you need. - Wayne at Pelican Parts
Check out some other sample projects from the book:
