replacing rear axle half shafts in '81 240D - PeachParts Mercedes-Benz Forum

Bill in SJ · #1 07-14-2004, 11:12 PM

I need to replace the rear axles in my '81 240D. How do I tell if it has the homokinetic or the annular half shafts? How difficult a DIY job is this? Which manual will be best for step-by-step instructions?

JamesStein · #2 07-14-2004, 11:48 PM

I'm not sure what the visual difference between the annular and homokenetic axle is. I bought a pair of reman axles from carquest for $69 each and they fit. I think that they are actually interchangable.

Its an easy job just a little frustrating.
You'll need a 17mm Hex which can be a pain to get (I got mine at AutoZone). And a sturdy pair of snap ring pliers. The ring that holds the axle into the diff is a pain in the rear to pull out. Don't be tempted to get on of the interchangble types you'll need something very sturdy to get the rings back on.

Loosen lug nuts on both rear wheels.
Jack up rear. Put on stands.
Remove both wheels.
Take 8mm deep socket or socket with 4in extension and remove the bolt inside the rotor (this holds the axle in). Do both sides. I put the lug nuts in the rotor and used a bar to hold the rotor still.
Take 17mm hex and remove the fill plug on the diff (top plug)
Once that one is off remove the bottom plug. (You don't want to get the bottom off, drain the diff and then find out that you can't get the fill plug out).
Remove the 4 bolts on the diff frame mount. (support the diff with a floor jack and a block of wood or something).
Lower the diff (I let the left axle rest on the muffler pipe)
Remove the diff cover (8 bolts)
Jack the diff up as high as you can
Pull the outter end of one of the axles free from the wheel bearing. (you might need a long socket extension and a hammer to knock it out.)
Lower the diff while pushing the axle to the rear.
Grab the snap ring in the diff and yank it out.
The axle should pull free.
Do the reverse to install the new axle.
Curse like a sailor as you bust your knuckles 4-5 times trying to get that darned snapring re-installed.
Repeat on the other side.

Put everything back togehter.
Re-installed drain plug on diff
Fill with your favorite gear oil till it flows out of the fill hole.
leave your drain pain under the diff.
lower the car (make sure you've put the wheels back on)

Either struggle to get back under the rear to re-install the fill plug or jack one side back up.
Go for a short drive.
Check for leaks in the diff.

All done.

Bill in SJ · #3 07-15-2004, 09:31 AM

thanks for the thorough outline.

flash123 · #4 07-17-2004, 07:54 PM

This post has been a big help.

Thank You

Pat

Bill in SJ · #5 07-18-2004, 12:13 PM

So, I trundle down to CarQuest & ask about the part. They ask me if it is an 8mm or a 12 mm. Nothing about annular or homokinetic. I even showed him the picture. He had no idea. Can anyone enlighten me? Thanks.

Mine is the old homokinetic, but I'm assuming from the discussion here that the annular ones fit up just fine.

The good part is that they want $75, instead of the $312 at MB.

JamesStein · #6 07-18-2004, 12:53 PM

Likely its the 8mm. Thats what mine were. To check for sure pull one of your wheels off and see what the size of the bolt on your current ones are.

flash123 · #7 07-18-2004, 01:22 PM

Local parts counter asked the same question. We assumed it must be the bolt that goes through the rotor. Wharehouse shows 11 of the 8mm in stock and 2 of the 12mm. My guess is that 12mm are rare.

Local parts dealer wants 59.95. He runs a special all the time on front wheel drive half shafts and he quoted me the same as if it were FWD. We went in Saturday. He does not stock them, but expects to be able to get them from the wharehouse Monday morning. Auto Zone quoted $99.00 or 149.00.

I'm not even sure they are bad, but the boots are rotted and split. For $60 each, it may be cheaper than having the boots replaced.

Pulling the clips was a hassle. I fought trying to grab the hole and pull. I finally used two small screwdrivers and pushed the clips off quite easily, and the naturally locked up the gears. Once the axle halves were removed it was eaqsy to rotate the driveshaft flange and get them out. Getting them back in is another question. I have until Monday to figure it out.

I am thinking about grinding, heating, bending and drilling a pair of neadle nose pliers. then pressing a pin into one jaw and reheating them to re-temper them, so that the jaw is bent with a spot under the chin ground away and with one tooth in the middle to stick through the hole in the clip and fit into a hole in the upper jaw of the pliers.

samiam4 · #8 07-18-2004, 10:59 PM

I pulled the clip last time with a cotter pin puller from Lowes or HD? It was a $6 tool and I was stuck with a bad axle out of town.

Homo vs Anular style- I think lobro only currently produces the Annular style. Most rebuilders use the older style axles.

Generally, if the boots are shot , there is damage to the boots-but you are a 240d not a 300 turbo diesel so there maybe some difference.

I had no problems poping the c-clip back on with the same tool. Just got to steady everything with a finger or two and push. Do you own a real set of 90 snap ring pliers-not the multiple replaceable end models. They are probably under $10 from snapon or the likes and it will work easily.

Michael

Best of luck on rebuild axles. Life on them is very variable.

flash123 · #9 07-28-2004, 02:28 AM

Thanks to Bill for starting this thread it has been extreamly valuable.

Thanks to James for a detailed description

Regarding annular vs homokenetic ;

I ordered axles form a local parts house (Inaba in Riverside Ca. $59.95)
I got 2 different axles
One looked like the original
One had a collar with allen screws. It looked beefier. He said it looked like ones used in VW's and BMW's
Both had the same part number but were quite different. He asked if wanted one of each, since both should work the same. I replied "No thank you, it would look strange." I chose the beefy looking one instead of the OE looking one. I thought it looked more like a modern FWD. He had a replacement in a few hours.

Prior to the replacement, I had a loud clunk that I thought that I had traced to the U joint in the driveshaft. After the axle halves were replaced the clunk was gone. The play in the rear end is gone. I also replaced the center driveshaft carrier bearing and the two flex joints.

Prior to the axle and driveshaft service the transmission shifted poorly. It shifted OK if I was slow and carefull but unless I went slow, the gears would grind. I had changed the transmission lube to Redline MT90 a few weeks before. That had not made any change.

After the service, the trans shifts smoothly and perfectly. Go figure?

Posts on this site suggest Mobil One gear lube for the rear end. Racing shop near California Speedway where I got the Redline endorsed Mobile One, so I went for it.

BTW, the axles were shot. The boots were rotten. The flex disks were cracked, but the oil in the rear end was almost clear and smelled like steak and lobster with baked potato. OK not exactly like steak and lobster, but it did not smell bad like the stuff I would expect to find in a 25 year old rear end. It looked like it had been put in yesterday. There was no evidence that the rear end had been touched in years, if ever. Go figure?

BTW the drain plug is 14mm on my 1980 240D, and could not be found at Auto Zone.

Eric Eliel · #10 07-28-2004, 12:15 PM

The drain and fill plugs on my 84 are 14mm hex. I got the 14mm from Grainger.

I've done this job twice.................replace both axles at the same time, unless money is extremely tight and you don't mind doing it twice. :-(

It only takes another 25 minutes to do the other axle once everything is apart. I don't like this job, although I'm getting pretty good at it.