CV Axles

Including Ball joints and Tie rods

Having weird clunking sounds while driving or the steering wheels starts to shake when you are driving and getting worse with increased speed? Also the tires get worn excessive at one of the sides? This could be a sign that the CV axles going bad. It is possible to change out just the CV axle ends and not the whole axles, however it is more time consuming and often easier just replacing new complete axles. Changing the entire axles will only be covered in this article. The job can be pretty extensive and complex if you have not much experience in working on cars due to the requirement of time and many tools needed. Although it can be straight forward if you have some knowledge of mechanics. If your car have driven in a rust environment and you don’t have special tools, then maybe skip this job!

This will be a long one so fasten your harness and prepare a big tea pot!


There are some considerations to be done. The original axles will probably fit the car better than after market ones. I find a lot of complaining around forums for poorly fitting after market CV axles for front wheel driven cars. Some cheap brands in reality sometimes use refurbished old axles and pack them with little grease and they might end up making sounds and break after a short time. Therefore be sure not to throw out your original MB axles without really being sure about changing them. Getting new MB axles for the B-class I would not recommend since they are crazy expensive and not offering any benefits other than being original. A good middle way could then be to buy a CV joint end refurbish kit. However this procedure is not covered here.

I wouldn’t buy the cheapest, but not the most expensive you can find either. Choose a brand you trust in the middle range. That will be 95% as good as the best ones. Also make sure the lengths and fitting are correct before ordering, parts stores list all kinds of variations, and manual and Auto/CVT variations are different even if they look similar in images.

There is a high chance you need to change the axle seals from the transmission while changing the axles. This could be because of age or they get damaged when removing/installing the axles. I didn’t think of this and one side started leaking a lot and I needed to take out the axle again. The axle seal for the CVT version I could not find in any online store, and needed to order one from Mercedes dealer and prised as such too!

You can be sure to need changing the lower ball joints and tie rods unless they have been changed in the last few years. This will add the need for a wheel alignment after the job. This needs to be done at a workshop unless you have really advanced equipment and training. A wheel alignment is quite cheap though compared to the changing of the drive shafts, so I would still consider changing the CV axles DIY.

There is a chance you will need to refill some transmission oil if some leaks out during installation. This is a good opportunity to change the filter and gear oil. This however requires you to have a dipstick and more parts on hand. Mercedes does not want their customers to change their oil, so they “sealed” the cap off and there is no dipstick. You can get a disptick for 5 bucks at Ebay, good filter kits also include the little plastic tab. Changing transmission fluid will not ne covered in this article.

You will need some special equipment for this

  • E-Torx bits (for removing bracket to right side axle and the ball joint bolts might have them)
  • Large star socket (for the original axle end bolts)
  • Glide hammer (to remove axle shaft seal)
  • Torque wrench
  • A good selection of spanners
  • Large and powerful tie rod and ball joint remover
  • Large sockets or similar to fit over the axle seal lip
  • Various lengths of socket extensions
  • Large soft ended hammer
  • Hex wrenches
  • Thread lock
E-Torx E14
E-Torx E14

You will need the following parts, depending on ambition level

  • Left side CV axle, is shorter than the other
  • Right side CV axle, is longer than the other
  • 2x Axle seal/ transmission output seal
  • 2x Ball joint
  • 2x Tie rod
  • CV moly grease
  • Ball bearing grease/assembly grease
  • High temp anti-seize alu-paste
  • 1L Transmission fluid – type depending on your transmission
  • Optional: Dipstick /Auto Filter/gasket

If you decide to go through with this job, be prepared that the tie rod might have rusted completely to the hub/knuckle. Then you will need large amounts of patience, cutting and drilling to get it free. I really hated this part. You are hereby warned.

Plan for not driving the car in a few days. This might take you longer than you expect. If you see an obstacle you cannot fix and you need the car, then quit early before the point of no return. I had not planned it very well and lacked both tools and parts thought the whole process. So the car was jacked up on stands while I waited on new parts to arrive. I guess this is how you learn. Luckily I had a backup car so there was no stress. Although I didn’t plan that the car could not be driven for over 2 months straight…


Before you raise the car, you will need to loosen the huge axle spindle nut. Take off the middle cap from the rim. If there is a dust cover hiding the spindle nut, then just raise the wheel with a jack and take the wheel off. Then remove the dust cover for the wheel hub, put the wheel back on and lower it to the ground again. Then loosen the spindle nut, use a long breaker bar because this one sits really tight!

Wheel hub dust cap
Remove wheel hub dust cap
Axle spindle nut
Axle spindle nut. The original is this star shaped. New after market CV axles comes with normal socket nuts to replace these.
Loosening axle spindle nut
Loosening axle spindle nut. They sit on tight so use a long breaker bar.

Do this for the other wheel if you plan to change both CV axles. After you removed the spindle nuts, you will need to raise the entire front of the car so you can get access underneath, so put it on safe on jack stands.

Next is two different ways to loosening the tie rod. The easy way if it’s not stuck. And the hard way if it’s stuck.

The easy way

Since this is the easy way, you don’t even have to take the caliper or brake disc off! Super easy right? If working on the right side, turn the wheel completely over to the right to get better access. Opposite for the left side obviously. Spray the tie rod bolts and the lower ball joint with penetrating fluid and let it work a few minutes before continuing.

Start by loosening the 19mm tie-rod nut on the hub knuckle assembly with a socket. The tie rod will stick to the knuckle arm because of the press fit, so the bolt will loosen by itself. Now you will need the heavy duty tie rod/ball joint puller tool. Place it over the tie rod and pop it.

Loosening tie rod bolt
Loosening tie rod bolt
Tie-rod puller
Snap off the tie rod with the ball joint tool.

Hopefully it will snap off and it will look like below:

loosened tie-rod
Tie-rod loosened

Now move over to loosening the lower ball joint. Since this is the easy method, you can avoid loosening the ball joint completely from the the lower suspension arm, unless you want to change the lower ball joint which I highly recommend. Use a 22mm spanner, you are not able to fit a socket over it. This bolt can be very tight so you might use a bit of muscle. You will normally not need a hex to stop it from turning when loosening since it is press fitted after tightening. The image below is in fact from tightening, but shows the same.

Lower ball joint
Loosen the Lower ball joint with a 22mm spanner. The hex is only needed when tightening. It is press fitted.

Hopefully it will look something like this when loosened:

Loosened ball joint nut
Loosened ball joint nut

Now get the ball joint puller tool again and snap off the ball joint from the steering knuckle. I don’t have a picture of it here, but you should figure it out since you did the exact same procedure on the tie-rod like 5mins ago.

After it is snapped loose, get a long pry bar, place it in the inner hole of the lower suspension arm and press down as far as you can with the bar leverage. This will enable you to lift the steering knuckle out of the ball joint.

Ball joint w245
Free ball joint of the steering knuckle. It is possible to free the CV axle spindle from the hub.

Withe knuckle free from the ball joint you can now easily free the CV axle spindle from the hub. You can normally drive it out with not too much effort.

The right side CV-Axle

The right side is slightly more complicated to remove, since it is longer and has another bracket under the car. Locate the bracket, it is secured with two Torx bolts.

Right side CV axles
Right side CV Axle. Contains a bracket in the middle.
Bracket for right side CV axle
Bracket and torx bolts

Now you can go ahead of pulling the CV axle out of the transmission. It might take a bit of force. On this side there is no place you can pry off the axle either. Be sure to have a drip pan under the transmission in case fluid runs out.

Right CV axle input into transmission housing
Right CV axle input into transmission housing
After CV axle is removed.
Bracket After CV axle is removed.
Right side CV Axle removed
Right side CV Axle removed

Left Side:

The left side is a bit easier, it can be pulled out straight away after the tie rod end and the ball joint have been loosened. It’s nearly impossible to pull the drive shaft straight out, due to the locking spring on the inside. Get a pry bar with the flat end and fit it between the inner edge of the drive shaft and the transmission housing. This will loosen the drive shaft from the transmission. Be ready for a drip pan if transmission fluid leaks out.

Prybar slot drive shaft
Prybar slot for left side drive shaft
Left side drive shaft loosened
Left side drive shaft loosened

The Hard Way

Let us imagine that the tie-rod is completely stuck and you cannot remove it with a tie-rod tool, either it breaks or it will not budge. Then what? Let me show you the hard way to fix this. In order to do this, you will need a set with good quality and new sharp drill bits. Also you will need to use an angle grinder. Rub on that patience lube you have in the bottom of your tool kit since you will need it! Let me show you how below.

Unbolting tie-rod
First step so easy. Unbolting the tie-rod.

First you will try to undo the tie-rod like normally, then your tool breaks or bends or worse. So your mind realise it is not budging at all. Fuck! You might be tempted to use a large sledge hammer to knock it free. Do not under any circumstance try this because you might end up bending the knuckle hub assembly. Do not bother to use a blow torch with heat either, it will not work and you will just end up burning the ABS sensor. The tie-rod sleeve will definitively burn up, but it will get ruined now anyway when it is this stuck.

Forcing the tie-rod tool
Forcing the tie-rod tool until it breaks. Failure!

To get better access you will need to remove the brake disk. Unbolt the caliper and hang it up with some wires to reduce the stress on the brake hose. Now bend the brake dust slightly shield out of the way, or unless it is rusted like mine, just tear it off.

Cut tie rod stud off
Cut tie rod stud off to prepare drilling. In the image you can see the tie-rod sleeve is burnt, so yeah I tried heat with no success. Do not bother with heat. Just start drilling.

Now the long and tedious process start. It is not without risk. If you do not take care you will need to replace the entire knuckle hub assembly. It will need to be replaced if there are scores inside the tie-rod insert after you drill it out.

Start by drilling with a small sized drill to make a pilot hole. Make absolutely sure that is in the middle other wise you will get out of the center line and might end up scoring the hole. You are hereby warned. The more narrow the drill the easier it is to get it started in the beginning. Use low speed and stop to apply oil to the drill bit head often in order to cool the drill bit head. Otherwise you will need to replace the drill often. This metal is super hard and will take a lot of time to get through. If you take it slow and use oil often it will not wear out your drills. Drill at least one centimetre before increasing the drill size. I used between 2-3 hours to get through the tie-rod before it popped out.

Drilling tie-rod
Drilling the tie-rod with narrow drill bit at the beginning. Go very slow and apply plenty of oil to aid in cooling the drill bit.

After you increase the drill bit size, make sure you don not score the knuckle hole. Go very slow and swap between the narrow and thick drill bits after you have gone a bit deeper.

Increase drill bit size
Increase drill bit size after you have a decent size hole. you will need to swap between them as you go along.

When you have traversed the entire length of the knuckle arm, about 2 centimetres, do not increase the drill bit further. Now grab your trustworthy punch drive which can fit in the tie-rod hole which you have drilled. Use some force and I’m sure will pop out. Try a few different sizes and continue drilling if it will not pop out.

Tie-rod drilled out
Tie-rod drilled out. This is the leftover which only let go after removing over 90%. Very stubborn indeed.

The ball-joint for some reason is not usually this stuck and can normally be removed by the ball joint remover tool. If this is completely stuck as well, then you might require help from a workshop, since it is very much harder to access. Have no solution for you here.

Changing drive shaft-transmission seals

I highly recommend to do this step since it is a high chance it never was changed prior and might start leaking. It is also easy to damage it when taking out and inserting the new drive shafts. I learned the hard way, it started leaking and the car probably lost 05.-1L of transmission fluid. And I had to take out the left side CV shaft out again. I did not change them initially since I got the wrong seals from the place where I ordered the rest of the parts. They did not have the right ones, especially for the CVT transmission variant I think they are hard to find? Anyway I needed to get them from a Mercedes dealer. And the price was 60$ each… OMG that is excessive! Anyway this is how to change them.

Removed drive shaft seal
Removed drive shaft seal

You will need a slide hammer puller to get them out since they will sit incredibly hard in the transmission housing. Put the new ones in your freezer since the outer diameter will shrink slightly and it will be much easier to insert into the housing. Timing here is essential. Get the old ones out before you ready the new ones. If there are any scores or rust marks in the inner edge of the transmission housing, you will need to use a bit of fine sand paper and polish the surface clean. I promise you it will leak if you skip this step. You will only have one shot of getting the new ones in. If they go in crooked and you bend them, you will need to get new ones. Therefore it might be smart to practice getting in the old ones back in first if you never did this kind of job.

Installing requires an equal size socket tool which matches the outer diameter of the seal. Get your favourite grease ready to easy the inserting of the seal. I used ball bearing/ hub grease. Use a long socket extension which you can pound on. Now when everything is ready, run and get the new seal out of the fridge and be as fast as possible, every second here counts! Grease up the new seal while it still freezing and install.

Grease up the new seal
Grease up the new seal while it is still freezing cold.

Use the socket and tap it in with a rubber hammer. Make sure to tap it in carefully and checking often that it goes in straight. When the outer edge of the seal is parallel to the outer edge if the transmission housing it is in the right place. If you overshoot, then you have to pull it out again. There is no end edge in the housing which tells you when it is in. So it is very easy to drive it too far in. The inner dust flap of the seal will stick out from the edge and will fit inside the drive shaft dust cover.

Tap in the seal
Tap in the seal
New seal in place
New seal in place. Notice the outer edge is parallel to the transmission housing.

Now you should be ready to put in the new drive shaft.

Fitting the CV drive shafts

Try not to pull the CV shafts apart since you might end up in a situation where the balls inside the joints will fall out of their sleeve and the joint will not function properly. First lets do the right side.

Fitting the Right side

Firstly put some grease on the drive shaft end that goes into the transmission. This will aid the locking ring to slide into place.

Grease drive shaft end
Grease drive shaft end

Use a rubber hammer and knock in the drive shaft into the transmission, make sure it is all the way in. The shaft should now line up with the intermediate bearing bracket holes. Use some thread locker on the bolts and tighten to reasonably tight.

Frive sahft intermidiate right side bracket
The right side drive shaft intermediate bracket should line up. Use thread locker on the bolts and tighten

Fitting the left side

Fitting the left side is just as fitting the right one, except the intermediate bracket fastening. Be sure that the drive shaft is far enough in so the dust cap goes over the inner seal rubber flap.

Fitting the end

If you need to change the lower ball-joint and the tie-rod, this is how you do it.

Remove the lower ball joint. Here you will need the E-torx if it is the original one still attached.

3 E-torx bolts securing the lower ball-joint with the suspension arm
3 E-torx bolts securing the lower ball-joint with the suspension arm

Once it is off, use a round wire brush to polish the inside the ball joint hole and the tie-rod insert hole. This is to remove any rust or left over dirt. This is a very important step in order to make them fit snugly.

Polish the lower ball joint hole
Brush the lower ball joint hole

Then use the same brush to clean the tie-rod hole.

Brush the tie-rod hole
Brush the tie-rod hole

Remember the tie-rod that might get stuck. Now use some anti seize Alu-paste to lubricate the lower ball joint and tie-rod holes before fitting them. So the same situation will not happen again if you need to loosen these again. Prepare for the worst you know.

Alu paste in tie-rod holes
Anti seize Alu paste in tie-rod holes

Ready now the new parts for fitting.

New parts vs old
New parts vs old. The older are a bit crusty. The left side is the cut one which was stuck and cut, needed a change here.

The new ball joints will usually have normal bolts instead of the E-torx ones, except the ones I ordered didn’t come with new bolts so I had to reuse them. This is totally fine. The top bolt always are new, do not reuse these, since they have a locking plastic ring. So here you don not have to use thread locker. Since you have to use a spanner to tighten the ball joint bolt, you can not use a torque wrench normally, so tighten with some force within reason. It will be pressed in the fitting and will not come loose.

New lower ball joint fitted
New lower ball joint fitted.

Before you insert the CV shaft into the hub, you will need to polish the inner hub surfaces. It is probably a bit rusty. Clean it up with sand paper so it is completely smooth.

Rusty inner surface of hub
Rusty inner surface of hub. This needs to cleaned with sand paper.

Use some CV lithium-moly grease for the interface between the CV shaft and the hub. This is important to keep noises and vibrations from the hub after you fit a new CV shaft. This is a common problem on front wheeled drive cars, the knocking after you replace completely new axles. Especially on Volkswagen and Audis. M ake sure to follow their recommendation with using CV moly grease.

CV Lithium moly-grease
CV Lithium moly-grease
Grease the inside of the hub
Grease the inside of the hub with CV moly grease
Grease the inside of the CV shaft where it interfaces with the hub
Grease the inside of the CV shaft where it interfaces with the hub

You do not have to grease the spline where it goes into the hub. Since you want to avoid slipping change of the drive gears.

Lower ball joint
Loosen the Lower ball joint with a 22mm spanner. Use a hex. wrench to hold the stud from rotating.

Now mark the spot where the tie-rod was and unscrew it from the steering rack rods. Put the new ones in in the exact same length as the ones you put out. You probably still need a front alignment job after this, but might at least make the car go somewhat straight meanwhile. Put some anti seize alu-paste on it.

Steering rack rod
Steering rack rod. Put some anti seize alu-paste on it!

After tightening then put on the tie-rod end on the hub knuckle assembly. Use at first a spanner and the hex to keep it from spinning, then tighten snugly. Then move over to the torque tool and tighten it to 60Nm.

Tightening tie-rod
Tightening tie-rod. Tighten to 60Nm.

If you removed the brake caliper, these bolts needs thread locker and then tightening to 115Nm. The little bolt to the brake disk which goes on the hub needs thread locker and only 15Nm.

After tightening the tie-rod, the only remaining is to tighten the CV drive shaft spline nut. To to this, the wheel have to go on first. And then lower the wheel to the ground so you can tighten the nut. The torque tool has to be set to 100Nm and then then tighten 60 degrees more after your each the torque setting. Prepare marks on a circle so you know roughly how much to torque. There is even apps on your phone to to this, or make circle from paper and put it on yourtool. Or buy a tool which tells you exactly the degrees.

Tightening the CV drive shaft nut
Tightening the CV drive shaft nut. 100Nm then 60 degrees.

After torquing the drive shaft spline nut, raise the wheel up. Take off the wheel. Put the hub dust cap back on then put the wheel back on.

If any transmission fluid came out it the time to replace this with the exact amount which came out. This might not be needed, depends only if some transmission fluid ran out during the job.

Take the car for a test drive and listen and feel if there are any weird sounds or vibrations. If all good you are done. Consider you a master of mechanics DIY jobs. This job is not easy and you should be very proud!

Robs Out!

By Robs

Passionate about vintage Mercedes Benz where driving, maintaining and learning new things and teaching others on the black arts of car maintenance.

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