can driveshaft be welded
Your engine and gearbox are the dream team, but if all their good work can’t get to the wheels, it’s all in vain. That’s why your driveshafts are very important indeed. But, as they’re charged with the task of handling the power, they can fail over time. You might snap one, or shear the splines off one, or you may even bend one if you hit something particularly unforgiving.
If any of that happens, you needn’t panic too much. Changing your driveshafts is actually a simple task that a home mechanic can undertake without too much trepidation. It’s just a case of being thorough, being safe, and of course, having your trusty Haynes Manual to hand.

How to change your driveshaft

This is a basic explanation of the procedure on a typical front-wheel-drive vehicle. Your Haynes Manual goes into full detail for your model.
1) Crack the hubs
While there is weight on the car, remove the split pin from the hub nut, then crack the hub nut off so that it’s loose. Don’t take it all the way off though. It will be a big nut, approximately 30mm, so you’ll need the right socket. And you’ll need a lot of effort because they can be torqued to over 250Nm. 
2) Jack the car up
You’re not doing anything with the car on the floor, so get it jacked up and on axle stands. The stands are not only for safety reasons here, you also need the wheels to be in the air  - ramps won’t be any use here. 
3) Wheels and brakes
Take the wheels off, put them under the car for safety and then start on the brakes. You’re going to need to remove the caliper, but you won’t need to disconnect the brake line. Use some sturdy cable ties or metal wire to suspend the caliper so there is no weight/tension on the brake hose
4) Hubs
Now you can free off and remove the hub nut completely. At this stage, you may also want to remove the brake disc – you don’t always have to, but it takes 20 seconds and makes for better access. 
5) Lower ball joint
Undo the nut onto the lower ball joint and then with the aid of a ball joint splitter, break the hub assembly and the lower arm apart. You should now be able to pull the hub away from the driveshaft, freeing the outermost end. In some cases (and this is where your Haynes Manual comes in) you may need to remove the anti-roll bar.
6) Gearbox end
The end of the shaft of the goes into the gearbox will either slide right out, or it will need some gentle persuasion due it being held in by a circlip. Consult your manual before yanking it too much and breaking it.
7) Now go in reverse
To fit the new driveshaft, just follow the above steps in reverse. Can't get the driveshaft back in? After making sure the splines are correctly lined up, tapping it with a rubber mallet should persuade it to install correctly. Job done! Make sure you tighten the hub nuts up to the manufacturer's specified torque. 

Replacing your driveshaft

Watch this video to see how it's done. Find the full step-by-step task for your model.

A very brief summary of the task:

  1. Remove the split pin from the hub nut, then crack the hub nut off so that it’s loose, but leave it attached.
  2. Jack the car up, remove the front wheels and take off the brake calipers. Remove the hub nut completely. 
  3. Undo the nut onto the lower ball joint and break the hub assembly and the lower arm apart. Pull the hub away from the driveshaft, freeing the outermost end.
  4. Remove the driveshaft end from the gearbox.
  5. Fit the new driveshaft. Make sure you tighten the hub nuts up to the manufacturer's specified torque. 

How long does a driveshaft last for?

The driveshafts of your car are exceptionally important, given that they take the power from the engine and send it to your wheels. Despite their importance though, they’re not a service part, and this means there is no set interval for when they should be changed. Every car is different. The key to driveshaft longevity is preventative maintenance as well as just generally looking after them.

If you look after your driveshafts, they can last the lifetime of the car. It only if you ignore the information below that they can become a problem.

The main shaft of the driveshaft unit is just a bar of metal, and as such is pretty robust. The only way this bit fails is if it’s damaged, or if the rust is allowed to eat it away. As such, there is no harm in getting under your car with a wire brush, clean up the shaft and give it a new coat of rustproof paint. This will extend the life no end.

Other than that, there are two main points of failure, they are:

The splined ends

Each end of the driveshaft has a splined input piece. It is these splines that allow the driveshaft to be acted upon by the gearbox, while at the other end, they allow the shaft to act on the wheel/hub, thus delivering power.

If these splines are damaged, the shaft can start to break up and shift, meaning the power isn’t delivered. In situ, these spines are pretty hardy.

However, if the car is driven hard, this can damage them. Also, if the car is modified to produce more power, it can be too much for the stock splines and can strip them from the shaft.

The most common issue is at the hub/wheel end. If the car has to have any work done that involves taking the hub off, so suspension work, a new wheel bearing, that kind of thing, if the hub isn’t fitted correctly, it can damage the splines.

The CV joint

Driveshafts have a constant velocity joint at either end to allow the shaft to move with the suspension and steering of the car. These joints are packed with grease to keep them happy.

To keep all that grease in place, you have a CV boot, a rubber cover that flexes with the movement of the shaft. If this cover splits or comes adrift, dirt can get into the grease.

When that happens, the dirt grinds against the metal of the joint, eventually breaking it. New boots cost around $20 each, which is a small price to pay when you consider that new driveshafts cost hundreds of dollars to replace.