S30 owners have a problem on their hands that enthusiasts weren't all that worried about ten years ago. The original half shafts that have kept these Datsuns running since the 1970s are starting to wear out, and every year they're harder and harder to find. That rhythmic clicking noise when you're making a turn, or a torn boot dumping grease all over your suspension, means it's time to make a call.
Parts availability really matters. Parts are easier to find in some places than in others, and the costs can swing wildly depending on which direction you go. Make a bad choice, and your car might sit in your garage for months on end just waiting for the parts to come off backorder or for a machine shop to wrap up the custom work. To keep a 240Z, 260Z or 280Z running and on the road, put some thought into what actually works best for your goals and your budget.
Look at the rebuild versus replace choice so you can choose wisely!
Table of Contents
How S30 Half Shafts Break Down Over Time
On S30 half shafts, the rubber CV boots are usually the first part to give out. These boots make sure that dirt and moisture stay away from the CV joints and hold the grease where it can do its job. After 3 or 4 decades of heat cycles and road chemicals, the rubber gets brittle, and cracks start to form along the folds.
When a boot tears open, grease is going to leak out and make a total mess. You'll probably see it splattered on the inside of your wheel, or you might see dark streaks that run down the shaft. At the same time, water and road grime can get inside the joint and get mixed up with everything in there. All that nasty gunk blends with whatever grease is left, and it wears down the metal parts inside the joint.
Rust is another issue you'll run into with older cars like these. Any car that spent time in the salt belt (or anywhere with harsh winters) will probably have surface rust on the shaft. A little bit of surface rust won't kill your rebuild if the rest of the shaft looks decent. But deep pitting that actually eats into the metal is a much bigger problem. Make sure to check out the splined ends really close - moisture loves to pool up in there and cause the worst damage over time.
The big question is whether the damage stopped at the boots and grease or if the damage spread into the metal parts. A shaft that has torn boots might still be fine if the joints inside are clean - you could rebuild it and be all set. If the shaft has clicking joints or heavy rust, you're probably better off replacing it instead of putting money into a repair.
What Each Option Will Cost You
Replacement shafts are going to cost you quite a bit more. Brand new shafts start around $300 if you go with aftermarket parts, and the price can jump past $600 each if you want better quality or if you need an OEM part instead. OEM parts have become harder and harder to find as the years go by, and that's even more true for older vehicles. The harder a part is to find, the more expensive it's going to be, and you might need to wait a few weeks just to find a supplier who actually has one in stock.
A rebuild costs less for the parts. But the parts are just the beginning. Plenty of other costs pile up when you get into it. Labor is a big one, and it needs to get done somehow. You can pay a shop, or you can buy the tools and do it yourself at home. Either way will add quite a bit to what you wind up spending.
Every job needs the right tools, and CV work falls squarely into that category. Tools like CV pullers and boot clamps are what you need to get the job done right. Most car owners who work out of their home garage don't already own these tools. It might not be worth dropping money on the tools that you'll barely use if you're only going to rebuild one CV joint and you won't be doing this type of work again.
Time commitment is another factor that doesn't get enough attention in this situation. Your car might sit on jack stands for days or weeks as you wait around for the parts to show up at your door. Replacement shafts ship faster in some cases, mainly because suppliers usually stock them more reliably than the other options. But sometimes it doesn't matter what you choose - the wait ends up being about the same length, and your car isn't going anywhere in the meantime.
Every single cost in this situation needs to be doubled. A $200 rebuild on one side automatically turns into a $400 total because you have two sides to take care of. A $450 replacement shaft turns into $900 before you've even reached the installation or paid for the labor. These numbers add up extremely fast when you're on a tight budget and the funds are already limited.
How Much Power Can They Handle
After you've settled on a budget, it's time to take a close look at how well these shafts will hold up as you're actually out there driving. Price matters quite a bit. But performance needs to be just as big a factor in your final choice.
A rebuilt shaft with fresh GKN or SKF CV joints will perform better than original parts that have sat in a warehouse for the last 50 years. New old stock can look perfect from the outside, making it tempting. The grease inside has probably broken down after all that time. But when you drive it, you'll run into more friction and much faster wear. Fresh parts deliver the reliable performance that you count on.
Torque capacity matters quite a bit once you've done any work to your engine. The factory S30 half shafts were designed for around 200 ft-lbs of torque and work just fine for a bone-stock L24 or L26. An L28ET swap is a different story, though, and the same goes for any motor with performance parts - you'll probably push past that limit.
Some aftermarket replacement shafts can take 300 ft-lbs or more before they start to complain. That extra headroom really matters when you add a turbo or run higher compression ratios. Factory shafts might hold up for a little while under that increased load. But at some point, you're pushing them way past what they were originally built for.
Rebuilt versus new - your choice should depend on how much power your car is going to put out. A mild streetcar with a stock motor will work fine with quality rebuilt shafts as long as they use modern CV joints. A turbocharged build or heavily modified engine needs stronger aftermarket options that can take care of the extra punishment and stay reliable when you need them to.
What You Need for This Job
Once you get under the car and start the work, these two methods are going to feel quite different. A half shaft rebuild needs some specialty tools that most home mechanics don't already have. A CV joint puller helps you separate the joint without damaging other parts, and you'll also need a bearing press for taking them off and putting them back on. Snap ring pliers round out the basic toolkit for this job.
Replacement can be the easier option - you're just taking out the old shaft and putting in a new one. The swap doesn't need any specialty tools or equipment. The tough part comes when you're trying to find the replacement shafts themselves. Quality parts can be hard to track down and usually take some research to find them, especially for an S30.
You'll need patience, and you'll need to clean every part before you put anything back together. All that old grease and grime has to come off (we're talking down to bare metal) or your new parts won't last nearly as long as they should. As you pack fresh grease into the CV joint, take your time and get it done right.
Rebuilds have a learning curve to them, especially on your first one. Your first rebuild is going to take extra time as you work out how everything comes apart and how to get it all back together. Plenty of S30 owners skip the whole process and just hand the job over to a driveline shop instead. Professional shops have the tools and the experience to get the job done fast. It may cost a bit more. But it can be worth it if you don't have much time or if you're not comfortable tackling this work yourself.
Your comfort level with mechanical work will decide if you rebuild it yourself or hire a professional. Either way will keep your S30 running strong.
Better Options for Your Shaft Upgrades
We've already covered the basic rebuild and replace options. After those, you have a few other routes available if you want something better compared to what came as stock from the factory. A popular way to go for S30 owners is to swap in the half shafts from a Z31 or Z32 300ZX. The later generation models have way better parts availability (mostly because they're newer and there are just more of them still on the road). On top of that, these shafts can also handle quite a bit more power than the original S30 parts were ever built for. You should plan ahead with this particular swap, though. The shafts are going to need some work to mount correctly to your differential and hubs, and you're going to need some adaptation on your end to get everything to line up correctly.
Coilover conversions are another factor that can change which shafts you'll need. Swapping over to coilovers is going to change your car's ride height and the suspension geometry. Because of this, your half shafts might need to be of a different length compared to what came on the car from the factory. At some point, it just doesn't make much sense to rebuild your old shafts because they might not even work correctly with your new suspension setup.
You could also skip the swap option and just order some custom half shafts from a driveline shop. Most shops can build the shafts with modern CV joints that are stronger and smoother compared to what these cars originally came with back in the 70s. They'll make them to your exact length specs, and you can pick the parts that match your power goals and how you actually plan to use the car.
Most of these other options mean that you'll have to work with the flanges where the shafts connect to the diff. You might need to have them machined down, or you might need to find ones from a different vehicle altogether. It's more work, no doubt. But it gives you access to a whole lot of options that weren't available when these cars first rolled out of the factory.
Pick the Right Path for Your Build
The right choice for you depends on what you'll do with your car. Restoring it back to stock condition so it matches the original build as closely as possible works best with a rebuild - it lets you keep everything authentic and true to how the car looked when it first rolled off the factory floor. Factory specs matter quite a bit if originality is what you're after.
Modified street cars do well with the aftermarket replacements. Aftermarket parts strike a nice balance between manageable costs and the performance that beats out worn factory parts. Racing setups are a different story, though, and they usually need custom builds instead.
Location is a big factor as you make this choice. If replacement parts are scarce where you live, then a rebuild looks like the better move. You also can't install parts that take forever to ship out or might not arrive at all.
One strategy that's worth looking at is to have a backup set on hand. Plenty of owners rebuild one set of half shafts and then run another set on the car for everyday driving. The backups are already sitting there, ready to go when you need them. This takes away the pressure and allows time to get the rebuild work done right.
The best strategy for you depends on your situation. Your budget and your timeline should be first on your list when making this call. Then think about how you'll use the car and if keeping it close to stock matters to you. The parts market in your area also plays a big part in determining what direction is going to be realistic for your build.
Build Your Dream Car
You can rebuild or replace your half shafts to get your S30 back on the road where it belongs. What works great for one owner might not be right for another. How much you want to spend, how comfortable you are with the mechanical work and what you're after from your car all matter here. Consider all three of these and you'll land on the right choice.
Before you start anything, spend some time looking at what you already have. You'll want to pull your shafts out and look for any wear patterns - you want to see what's actually happening down there. An inspection like this stops you from guessing and will save you from spending money on parts or services you don't need. Whatever option you go with, make sure to address any half shaft problems when you see them. Strange noises and vibrations aren't going to fix themselves, and a breakdown miles from home is the exact type of headache you want to avoid.
Classic Datsuns need consistent attention, and the repair decisions can get messy fast. Drive a dialed-in 240Z, 260Z or 280Z, though, and all those issues melt away. These cars have a personality and heritage that you won't find in any modern vehicle.
We at Skillard can get you there when you have the basics covered and want to take your S30 past the standard maintenance. We make custom parts designed for Datsun owners - bumpers, aluminum door cards, center consoles, spoilers and plenty more. A full restoration needs different parts than a few targeted upgrades, and we carry products for either type of build. Most of our parts improve the appearance and capability at the same time. Check us out at Skillard.com to see the full product lineup and find the right parts for your build.
