Pictorial - Axle replacement

[micklongley]

Hello again everybody,
I would like to share how I swapped a driver side axle in my 1980 300SD. This is a 116 chassis but the process should be similar to most models.

A little history... My wife drives the car for the most part and she let me know that there was a dragging/scraping/clunking noise coming from the rear end. I looked underneath and noticed that the drivers side boot had cracked and was leaking fluid in the surrounding areas. I misdiagnosed the noise as a bad CV joint... it turned out to be the sway bar link dragging on the rim. Needless to say, I still have a noise but the axle is no longer leaking. I was able to source a good used axle from Pick N' Pull for $30 so that was the only way to go. Follow along as I show how I changed my axle.


- Start by jacking up the back end, make sure to support the car by the body, not the axle or suspension. Take the back seats out and locate the upper shock mount. Take the nuts off of the top of the shock and the suspension should droop a little as the tension is released from the shock.


- Drain the fluid from the differential. A great piece of advice from DieselGiant is to remove the fill plug first, then remove the drain plug. This is so you don't get stuck having a differential with no fluid and no way of getting fluid back in if the fill plug is frozen.


- Loosen the differential cover bolts, use a jack to support the diff and remove the 4 bolts holding the differential to the frame.


- Take the differential cover off to reveal the gear set. Locate the lock ring/clip. Mine is located just to the right of the leftmost spider gear in this picture. You may need to lower the diff to get a good angle on the clip.


- Close up of the clip to be removed. The easiest way for me to remove was to use two small electronics flathead screwdrivers and just push on each side. The clips could fly out so make sure you keep an eye on where it lands.

The next step is to use the floor jack to push the differential as far up as it will go -- this is to create distance between the hub and the differential so that the hub side of the shaft will come out easily.


- Locate and remove the bolt from the center of the hub. This is the only bolt holding the axle shaft to suspension.


- Once the bolt is removed you can gently tap the axle out of the hub using a socket extension and a hammer. Make sure to completely push all of the splines out of the way and the end of the axle is completely out of the hub flange.


- Now you can tug on the axle shaft and it will come out of the differential fairly easily.


- This is the axle I removed from a gas Mercedes with a 116 chassis. It is shaped differently but the shaft size is the same, as well as the spline count. The seals on the end match up the same on both axles. Notice the severe cracking on the older axle, the newer one seems like it should last a while.

The process to install the newer axle is exactly the reverse. Make sure you put the differential side in first - then the hub side, this is very important.


- The final result. Not bad for $30 and 4 hours.

I hope you enjoy and please leave feedback if you found this helpful.

Thanks,
Mick

[BioBens]

Nice writeup and pictorial. I just did this on my W123 (84TD) and everthing looks exactly the same and the procedure is ditto. I tied a wire to the c-clip and pulled/installed the clip with needle nose. Wow, 4 hours to do the job! I must be a half-fast wrench.

[AMH]

Beautiful write up. One of these days I will invest in a cheap digital camera, and post some of my "how to" articles. Right now it's difficult to use a 4X5 view camera under the hood/car with a tripod, film holders and black viewing hood.

Alan

Did you replace the axle seals at the same time?

[MattBelliveau]

Nice. This was a much easier job than most lead on to be. The first side took about 2 hrs for me, while the other one was ~20 mins. My biggest hassle was getting the c-clips back in...

[micklongley]

I didn't replace the seals at this time. It would be wise to do so but I totally forgot. I am swamped with work right now so this was a rush job. I would recommend replacing the seals in the differential while you have the axle out, it makes the most sense. I have a feeling that my seals will last a while though.

The C-Clips were tricky to get out, but fairly easy to put back in. I used a rag and applied constant pressure with need nose until it stayed on the axle by itself, then I gently tapped it into place with the needle nose pliers and my palm.

Mick

[85 DSEL]

Nice write up Mick! I just did mine a couple weeks ago. I did go ahead and installed new ones from CVJ Denver and new seals as well.

I used a small pair of needlenose ViseGrips to grasp the clips and they worked great to re-install them!

If I had to do another axle replacement now, I'm sure I could do it in 3 or 4 hours. BUT, that doesn't mean a thing though as it will be 100K plus miles before they will need replaced and I will have forgotten everything I learned by then!

[sunnyintx]

Very nice write up.

We need them on one w126 (making a clunk -- not good), and will soon on a couple of the others. There's no noise or misbhavin' on the "soon" cars, but I can see the boots are cracked. Hey, it's old rubber -- what can I say? And since everyone says once the boots are cracked, you've gotta replace, not reboot, I guess we're stuck.

I was hoping to find some of the Chinese half shafts Dmorrison used on his w123, but I haven't found them for the w126. I'm going to check out Napa Monday, though -- someone on the Forum said Napa sells new for the same price as reman and both have a lifetime warranty. That actually means something around here, since we hardly ever let go of one!

I sent a query off to CVJ, too -- waiting for a reply -- but according their website they only handle reman axles for Mercedes. Has that changed in the last year? If so, I wonder why??

[Stevo]

Originally Posted by sunnyintx

And since everyone says once the boots are cracked, you've gotta replace, not reboot, I guess we're stuck.

Just because the boots are cracked does not mean you need to do anything but check them now and then. Most go for many miles being cracked.

[sunnyintx]

Thanks -- I spoke too soon!

I did some further reading and learned that "cracked" and "oil leaked out, joint in state of self-destruct" are not necessarily the same thing. Which is nice, since two of the three are fine, just cracked. I'ts only one that's actually got "symptoms" I can hear, and feel in the axles when she's up on the lift.

But what I did understand is that once the boot is fully breached and the factory oil has started leaking out, it's too late to reboot. Not that you can't keep driving the car until you get that old familiar clunking, but it's an axle replacement next.

[charmalu]

This is a great writeup/pictorial.

How did you remove the axles at PNP if Jacks are not allowed? since everything is up on those welded wheel jack stands. Removing the Diff mount can get exciting when it lets go w/o something holding it.

You used a jack for the Diff. to raise and lower the Diff. at home, but did you use a jack stand since you had the wheel removed?

Charlie

[JimmyL]

Originally Posted by charmalu

This is a great writeup/pictorial.

How did you remove the axles at PNP if Jacks are not allowed? since everything is up on those welded wheel jack stands. Removing the Diff mount can get exciting when it lets go w/o something holding it.

Ole Mick hasn't been on the forum since May it appears, so he might not get your question. I had to pull axles from a car at PNP, and not having a jack made it a bunch more difficult. I'll edit in the link here in a minute......
**Geez, harder to find then I thought**

http://www.peachparts.com/shopforum/showpost.php?p=1951927&postcount=29

Not having a 19mm socket for the calipers was almost a deal killer, and certainly made clearing the hubs much more difficult. Dropping the shocks a bunch gave me the room I needed to get the hub side of the axle out.

BTW Sunny, I bought an Astoria FB5000 Flexx gun for installing flexx boots onto axle shafts. I could bring that to your GTG and if you ordered some boots and clamps and had them on hand it could add to the info sharing of the GTG.

[DeliveryValve]

Good tips on the axle replacement. I've used and like using the two little screw driver method to remove the C-clip the best. But get a fishing magnet to get the clips out once they fly into the diff. Also, releasing the shock helps a bunch too.


This is another good thread about axle replacements following the ones from

dmorrison and Jeremy5848.




.

[charmalu]

Originally Posted by JimmyL

Ole Mick hasn't been on the forum since May it appears, so he might not get your question. I had to pull axles from a car at PNP, and not having a jack made it a bunch more difficult. I'll edit in the link here in a minute......
**Geez, harder to find then I thought**

http://www.peachparts.com/shopforum/showpost.php?p=1951927&postcount=29

Not having a 19mm socket for the calipers was almost a deal killer, and certainly made clearing the hubs much more difficult. Dropping the shocks a bunch gave me the room I needed to get the hub side of the axle out.

BTW Sunny, I bought an Astoria FB5000 Flexx gun for installing flexx boots onto axle shafts. I could bring that to your GTG and if you ordered some boots and clamps and had them on hand it could add to the info sharing of the GTG.

OH Yeah, I remember that with you laying in the rain and mud hole . that`s how the Hippies get a bubble bath, fart in a mud puddle.

I have pulled 7 axled from PNP, was wondering how he did it. I also droped 3 Diff. sometimes have to do some searching for a Jack.

Dropping the shocks and the springs just fall out when lowering the Diff.

You did good on your e-bay find.

Mick lives just a little south of me, maybe 40 miles, might have to look him up.

Charlie

[Doug183]

Sorry to revive an old thread but 2 things.

1) Thanks.

2) The right side C clip is much more of a bear to put on than the left (drivers side.) I bought some needle nose vice grips ~$10 hoping not to use them. After struggling with the driver side, broke them out and poof... magic... easy as butter. Now for the right side... no way. The nose of those pliers was not long enough for the angle that was available between the vice grips themselves and the angle of that big gear on the left and the spider gear on the right and the angle of the c-lip tab which faces inward - don't worry if this makes no sense to you, the moment you got to put the right side c-clip in - it will. Then in utter frustration, I put the c-clip in backwards - that is with the tab facing outward toward the spider gear. With the all the angles available, it actually went in easy enough! However, as the adrenaline rushes out of my blood and I was staring at my self created solution, it dawned on me that it probably was just a bad idea. Now getting that clip out with the tab pointing toward the gear, let me tell you, was impossible to do it the same way I pulled it out... with a metal kind of dental pick. The reason was now there was absolutely no angle to grant any leverage to use the little hole in the c-clip as no mater how you rotated the clip, the other side of the hole was covered by the axle. At this point I literally almost cried. After staring at it for about 30 minutes, I rotated the clip so now the tab was facing toward the front of the car far and I was looking at the two ends of the clip instead (the open end as it were) With some small screw drivers I managed to push the clip off! Victory right? NO!!.. Utter panic, as I couldn't fish out the clip with a magnet - it was really back there between two gears. I was terrified that I was going to have to remove the entire differential and shake it upside down like a piggy bank to get the clip out. At this point a tear might have actually welled up in my eye. I will swear to anybody it was sweat as it was pretty hot out this day, but... I sat under the car for another 15 minutes just staring until a last ditch idea hit me.

I removed both axles from the wheels (left them in the differential). Put the transmission in neutral and rotated the drive shaft with my hand. The entire internals of the differential moved! The clip fell with a nice 'clink' to the bottom of the differential where I could finally retrieve it. I know for you experts this solution might seem obvious, but to a newbie in utter panic, frustrated, out of simple solutions and mixture of diesel oil, gear oil and sweat filling my eyes, it was quite a breakthrough.

Ok how did I get the right side clip to stay on in the end? I swear I do not remember. I think a finger and one screw driver just so it would kind of stick a little. Then using two screw drivers to urger it on a little more than tapping it with one screw driver on each side of the tab a little at a time.

Just use this as guide of what not to do. Honestly after doing it, it is not a hard job but it kind of has to be done very specifically. Its also kind of dirty.