A common issue with Porsche CV axles when used on the racetrack is leaky CV boots. I experienced this early-on when I started taking my 987.2 Cayman S to track days, and following common advice on the forums, I just cleaned up the boot/axle, and installed new clamp nice and tight.
Good to go, right? No more leaks. I did this a few more times over the years as I had each boot eventually leak at the large end. Fast forward to 2025, I’m at the track and during fast left hand turns I’m consistently hearing big popping noises (similar to big rocks hitting the fender) from the rear-right corner of the car. We put the car in the air and found the wheel bearings had a little play. Not a big surprise since the car is closing in on 100K miles with some heavy track use.
I decided to replace the bearings at all four corners, but while I have the rear wheel carriers out I may as well re-boot and grease the axles. Here is what I found after disassembling the inner CV joint on the passenger side (where I was hearing those pops).
Ooh… yeah that inner race is toast. The bearings and outer race showed some significant wear as well. Turns out, that liquefied grease is now no longer able to protect these surfaces, and was not designed for heavy track use and temperatures. Once it liquefies, your CV joints are a ticking time bomb.
That commonly regurgitated advice to just re-clamp your leaking boot is not a good idea (and I am guilty of this myself). Now that we know, that what options are available?
- DIY Rebuild
- This was my intention, at first. The inner CV joint (damaged part above) is available new from Porsche for ~$300 each at the time of this post. I could then pack it with some better grease (Redline CV-2), put on new boots and clamps and should be good to go.
- This is when I discovered the outer CV joint is not serviceable on the Cayman/Boxster. The outer CV “can” is sealed/crimped in place, and the joint is not available new separately from Porsche. Your only option to replace this is to buy a new axle ($1,000+).
- I considered trying to wash all the old grease out of the outer CV, packing in new Redline CV-2, and calling it good. There are a couple problems with this, first being that I can’t inspect the CV joint so it may also be damaged, and second, grease compatibility is a major concern. Aftermarket grease may not play well with whatever ingredients are in the factory grease, and it will be near impossible to fully clean it out without taking apart the CV joint. This can also cause wear issues and CV failure.
- New OEM Axles
- As mentioned above, these cost ~$1,000+, each. You do get fresh CV joints, but these will have the same factory grease issues with track use.
- CVJ Axles – Rebuild & Race Prep
- While doing some reading online, I came across CVJ as a potential option. They offer rebuild and “race prep” services for Porsche axles, and they are even able to take apart and re-seal that non-serviceable outer CV joint.
- At the time of this posting, this service costs ~$688 per axle, and I was able to put together the details of what the service includes which I was unable to find available online elsewhere:
- Once the axles are received, they are completely disassembled. We use a proprietary method to carefully cut open the CV can to remove the internals (Important because this is not something you can easily DIY)
- All reused parts are put through two different part washers
- Parts are then put through two different media blasters
- Once clean, all parts are inspected for wear, especially contact surfaces. Threads are chased, splines are inspected, shaft is straightened to within 0.01″
- All contact surfaces are micro polished by hand
- New parts: high strength chrome moly racing cages, ball bearings, Rein brand boots, boot vent tubes to relieve pressure, high performance racing grease
- Reassemble axle, CV can crimped with silicone o-ring and tested for leaks. Inner can and cap sealed with Hylomar sealant.
- Paint and ready to ship
- Regarding the grease they use, which they claim is superior to Redline CV-2:
- High performance racing grease: Grease is specialty grease for linear and oscillating mechanisms and couplings, such as constant velocity couplings (CV joints) and sealed bearings. It will take heavy shock loads, frequent axial movements, large speed variations, and frequent reversing. It is made with a higher molecular weight synthetic base stock and will withstand extreme temperatures. It has a very strong resistance to water washout in rain or even salt water. Grease is designed for low oil separation under centrifuging. The grease is designed to skin over to create a shell that resists dirt and moisture, but this shell does not in any way detract from the lubricating qualities. For this reason, this is an excellent product for sealed for life bearings or large open gears.
As you might assume, I chose option 3. I did find some used, lower mileage (street-used) axles for my 987.2 Cayman S MT which I sent into CVJ rather than my abused axles with worn CV joints.
A note here, your axles might be VERY hard to find used depending on your exact spec. For example, my axles are specific to the 987.2 (09-12) S with manual transmission, which is a rare car since most 987.2’s came with a PDK, and not many were imported to North America following the 2008 financial crisis. Even more critical then to ensure you do this service BEFORE your CVs are wrecked, like mine, and save yourself some money and headache.
Here are the axles back from CVJ. They look and feel great, and you can see the boot vent installed. The axle itself is hollow so only one side needs to be vented, per CVJ. Also shown is that newly clamped/sealed and rebuilt outer joint!
I haven’t yet had the chance to durability test, these, and once I do I’ll add a follow-up to this post. Prior to shipping my axles off to CVJ, I did speak to a handful of people who had a positive experience, though, so fingers crossed this is the last time I’ll be dealing with CV axle problems for a while.