Well, I finally got my half shaft replaced in my 85 300D and I have some tips to share with all if you are planning to do this job soon.

I purchased Arn/Beckly *New* shafts and paid 150.00 each. They appeared to be exact replacement unlike the one KenD300 purchased from Mercedes Perf (The GKN shafts).

First of all, find a lift to this this work. It makes the job very easy.
If you can't get a lift make sure you have two bottle jacks, because you will need them, one for push up the diff and the other for leveling the control arm during the reassembly.

Second, I make a tool that would screw into the wheel shaft, sort of a beater bar that would help pull the new shaft through the wheel bearing. Made the job a snap! It's just a long bolt with a deep socket and washers. Make sure you get plenty of threads into the shaft before you start.

My diff didn't look like KenD300 diff. My 85 had a rear diff support with 22MM bolts (2) horzontial and four 13MM bolt into the body verticially.

Also, when you are preparing to do this job, go ahead and be ready to replace your rear sway bar bushings. The rear sway bar bushings had to be taken down to remove the horzontal 22M bolts. I notice the sway bar links can be done the same time you do rear brakes. Easy to do and not expensive.

So my prep list is:

Beater bar bolt w/ washer and socket
Wheel bearing grease
Swaybar bushings
Axles (of course)
Moble 1 syn gear oil
Black PVC gasket maker


Steps used to replace axles:

Remove rear tires
Remove 13MM center axles bolts
Remove swaybar links on each side
Remove both 22MM horzontial support bolts
Remove the four vertical 13MM bolts on the diff holder bracket
Remove the 17MM diff cover bolts except for bottom two
User flat tip screw driver to carefully crack open cover to allow fluid to drain.
Carefully jack rear diff to highest level leaving rear contol arms hanging
Remove C-Clips on each axle using one end of C-Clamp plier attached to vice grips (makes pulling the clip easy)
Start by remove the wheel bearing end of the axle, as you jack the diff it should pull away from wheel hub. You will have to go up and over the rotor once loose.
Reinstall the diff side of axle first then rotate the outer rotor until spline lines up inside wheel bearing.
Lower the diff slight to get a straighter alignment
Install beater bar to pull axle through wheel bearing. I had a friend at the auto hobby shop use a rubber mallet to help while I used beater bar.
Same for axle two.
Trick for C-Clips (six inch needle nose work perfect for reinstalling. Make sure you have adjusted diff with jack to achieve maximum axle input into diff. Tolerance is tight.
I cleaned the rear diff cover in parts cleaner ensure the vent was clear. Air dry. Acholol for the inside to ensure inner cover surface was oil free. Black PVC on the diff side.
Mount cover 17MM bolts
Mount 22MM bolts into diff holder and diff cover
Replace swaybar bushings and remount
Mount 13MM vertical diff holder bolts (use blue locktight)
Refill with gear oil
Remount tires

It will take you a good three hours to complete this job.


I have a 40mph hum which I strongly belive to be center bearing. Can someone tell me how hard this job is going to be and maybe some steps and tricks to remember???

Thanks,

Morph

You have set a good example of how to go about documenting what is used on a repair...I hope everyone about to do any repairs will take note,, and notes like you did and send then to the FAQ pages project. Thanks, Greg

I just had one of my half axles start to die (thumping) on me this morning...I hope I make it home.

Anyway I am looking at replacing the axle but after searching for parts and prices I have a few Q's for you...if you dont mind. I have an 85 300TDT by the way.

Here they are:
Did you use axles that were the 'old' or 'new' style? Not sure of the physical difference only that some of the hardware is different. I'm plannign on using a remanufactured axle.

Did you use new clips inside the differential? Did you just use all the old hardware (bolts etc).

Did you use the same shims? Did you need different ones?

Did you disconnect the flex disc from the rear diff?

Any advice. I'm not a nivice but this is my first adventure into the rear end of this car.

Thanks for your time,
Alec.

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85 300TD Turbodiesel 299,376 miles