The right axle shaft of my 1995 S320 (W140) recently sheared in half while pulling away from the lights.

How easy is it to replace the complete axle assembly? Is it simply a matter of removing the axle nut and unbolting the shaft assembly at the differential flange?

The old shaft should come out easy enough because it is broken in two but when installing the new shaft assembly does any of the suspension linkages have to be undone to allow clearance?

Finally does anyone know the size of the axle nut and the bolts holding the assembly onto the differential flange?

I can't think of a way your 3.2 could have enouth torque to have broken the shafts unless the cv joints possibly broke and locked from being without lube for a long time. Was it making noise which you ignored? Are the rubber boots torn up. Perhaps if you had a more detailed discription of exactly what part broke and where. OR photos would be even better.... the axle shafts are available but I don't think many are sold since they are usually very long lived IF the boots do not leak out the grease. Check with Phillip here at FastLane parts once you know what exact parts you require. Salvage yard parts might be used IF the wreck did not contact that area and the parts have good boots and are not bent from collisions.

Really good maintence is the key to a long life for your MB.

DanielW

NEVER heard of that part breaking --it MUST have some other condition to precipitate this failure--was the CV joint boot torn and the joint worn and rusty? Something real unusual going on.

Sounds like a defective part, maybe.

Outer end is held in with a bolt, just unscrew. Watch for washers and make sure to put them back in the same way, they are NOT flat!

Inner end is just bolted to carrier, I believe, unlike the older ones that were held in place on the diff inside by spring clips.

Axle will compress enough to remove it from the diff and then the hub. Be very carefull not to pull the inner joints apart, you will have to have a new boot installed when it's taken apart to get the "tripod" put back together!

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

The CV joints are fine and the boots were not torn. There was slight rust on the shaft where it sheared, just where the outer boot is fixed around the shaft. Maybe there was a flaw during manufacture that created a weak point?
The shaft is 1" diameter solid steel so it should not break.

Will I have to drain the diff oil before removing the old shaft or is the carrier sealed?

I am getting a s/h replacement assembly to fit this weekend, I have heard the bolts fixing to the carrier can be tricky to remove, any tips?

benm,

When you take it out, you can examine it closer to determine failure. Rust accumulating about where the boot is held is not uncommon in the rustbelt.

That shaft is heattreated steel- I'm guessing if you look at it with a Loupe and good lighting, you should see fine striations close to the origination (probably rust or a gouge), then over cyclic forces it broke. As the crack grew, it grew faster, hence the cleanist looking steel would be the last bit.


Michael

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Michael McGuire
83 300d
01 vw A4 TDI
66 Chevy Corsa
68 GMC V6 w/oD
86 300E