rear axle half shaft interchangeability?
 

on my 1985 cali 300D, the rear axles make a horrible clunking noise pretty much all the time. i bought the car this way and the PO told me they needed to be replaced, and that was about 6 months ago. anyways i'd like to finally do it before the axle breaks and ruins the car.

i would prefer to get junkyard axles rather than spend $300+ for rebuilds. ive seen some good ones that have newish looking rubber boots and was wondering if they would work. i think it was a 380sel but i could be wrong?

so my question is: what models/years will have compatible axles? do i need to find another 1985 300d or can i get them from any 300 series cars? i.e. w126 body styles?

ive tried searching for this but all i see discussion of is the cheap china axles which seem to be junk, and the cvj rebuilds out of denver that are quite expensive.

Hello.

I have had this same problem.

I replaced both my shafts on my 1984 300TD an one came from a 1978 230, and the other came from a 1985 300TD if i dont recall all wrong, some time since i did this.

In my experience, there is no difference in the shafts between petrol an diesel cars.

But the shafts from 1983 is all another story, that is the new type, that you just bolt on the differential.

This is just my experiences with the matter.

Keep searching
 

The threads you're looking for are there, just keep digging. Interchangeability matrices, pretty pictures, the whole shebang. Another way is to visit the epc web site and xref part numbers there.
Parts yard axles are fine, provided their boots have'nt already failed. The boot on the replacement can be cracked just not leaking, doubt if you'll find any perfect axles in the boneyard. The OE's are pretty thick and rugged. A few months ago I swapped in a passenger side axle from a 83 240 in mediocre condition and everything's peachy.
A safe way to approach your issue is to wait until you find suitable donor parts. If the diff doesn't look the same as yours, you better make sure it will fit. That said, most 126 model year axles probably won't work and I vaguely remember something like that mentioned when I was researching. In the meantime, you can always implement the band-aid solution, read: shortterm. I packed greased up in both halves of the boot and a half roll of duct tape later, me and the girl were good for a month or so. Was far too busy back then. First result on the search list for that:
http://www.peachparts.com/shopforum/diesel-discussion/269725-factory-cv-joints-longevity-w-o-factory-oil.html
Now, use common sense, don't think this will last forever. Temporary, as in several hundred miles and even then no guarantees.

FNHB

I would recommend swapping in an axle from another 123. The other models probably have different track widths or some other difference. AFAIK, all 123s use the same axle.

You'll need to replace them :(

It's not that hard of a job, but it is laborious as a DIY. Trust me, paying for the rebuilds is definitely worth it. For 300$ you're basically set for another 20 years of good axles.

In the meantime, buy some duct tape and blue chevron gear grease/goop or whatever it is called. It's thick and sticky. Clean the boot as best you can and fill up the boot with the goop. Then wrap it in duct tape. For added protection you can even clip on some zip ties to hold the tape in place.

However depending on how long the axle has been run without lubrication you might get a little more borrowed time before the axle fails.

I don't believe if the axle fails it will cause any damaged. You just won't have any drive power at that wheel. Can anyone please confirm if I'm right or not?

Edit: After I did my fix I drove almost 3000 miles on the damaged axles. When I replaced them I pulled off the tape and most of the grease gel stuff was still in there. So you may have a lot of time before it needs replacing.

Yup
 

I think you're pretty correct about that. That slow roll to a stop where you're mind covers all kinds of scenarios playing out. No harm resulting from all the cv axles that have failed on me over time, benzes and others.

Tried to drive her as little as possible, though as you experienced, everything still in intact when removed to put the "new" one in.

FNHB

Without lubrication, you CAN heat it up enough that it eventually welds to itself, freezing in whatever position it happened to be in when everything reaches the right temperature.

If that happens, you can do a lot of damage, your tire will start hopping, the car will shudder and drift with the vibration, you may damage the diff, wheel bearing, suspension, ect.

Ask me how I know this.

The plus side is that the car will be basically undrivable, so other damage in unlikely since you wont be able to push it.

Additional downside is that if that happens, you will have to cut the axle out to remove it. That was a major PITA.

i had the same issue on my 126. I used a good axles from a gasoline vehicle and turned out that they did not fit, but the actiual cv joint is the same, so i just took the cv joints off the good axle and put it on my original one. The only problem is that it could be hard to put them back together. Its a little tricky and took me sometime to figure it out. there are some videos on youtube that show how to do it.

W126 axles will not fit the W123.

When sourcing junk yard axles, be sure to get the spacer shims. You may need an od combination for proper fitment.

Do not swap sides.