W111 rear axle
 

Hi,

I'm doing some work on a W111 250 Cp rear axle. It has been messed a bit with, found different type bearings (one roller and one ball bearing) One anchor plate is from a W108 etc.

The question is about the lenght of the axle shafts, I think the left should be longer than the right? They are both equally long. Maybe someone has been improvising here?

Hope someone can enlighten me.

Regards,
Karsten

According my book the left axle should be longer, so apparently two right side axle shafts has been mounted.....

I'll have to see if the axle shaft from my spare rear axle will fit. It is an older one with drum brakes, but I hope the axle shafts are compatible. Changes to the splines were made at some point, I know.

Karsten

That is a swing axle , 3:92. Should be disc.
The RH axle is roller and the LH is ball.
Does the RH axle have a circlip on the end for the slide joint??

Yes it has disc brakes. Interesting that the roller and ball bearing combo is original, I would not have guessed this. Is it specific for this axle version? I do not notice it mentionend in my W111 book?

Here are pictures of the axle shafts:

Axle1

Axle2

Axle3

At picture "Axle3" you can see that the axle has not been riding on the full lenght of the spline.

Thanks, Karsten

The rh axle bearing is a roller/self centering type cuz this side goes through an arc and the pivot is under the C/L ... so , without this, you can get knocking, specially going around a right turn with negative camber..
The left side does not need this as the bearing and axle are always fixed to the outer tube/position..[ i.e. - they swing as a unit with the whole diff case]

But , I have seen guys replace it with the standard ball type. mostly due to cost and the roller is hard to find. [ SLS has them] without problems.
I would not do it myself.

Anyway, I think someone may have replaced an axle at one time .
The reason I ask about the circlip [ you do not have ] is cuz on those all axles were same size. That would be 280 version , I believe..

What does your comment about 108 mount refer to???
..and what is the problem with the rear?????

I could possibly reuse the old roller bearing, it does not seem worn at all. I will of course clean and inspect it first.

The question regarding the axle shafts is because my book states " There is a difference in the lenght of the rear axle shafts. The longer shaft should be installed left side" But these shafts are equally long?

The 108 comment refers to the anchor plate (the plate where the hand brake shoes are mounted) left side has a 108 number. I guess this is just the new type made from pressed sheet metal. The older one is casted iron.

Regards,
Karsten

Here is a link in German .. scroll down when you see an axle picture with an "I" , [ for information] .. click on it and you will see the reason for the self center roller on the right axle I spoke of ;
It is painly seen with their pictoral geometric picture. Note the red C/L as the swing goes through the arc. They have English tanslator ....

http://213.239.220.84/bin/dbframes.phtml?mid=IN02

I think someone put a right axle in the left side at one time ...

What is the problem with the diff . to begin with??

?

I took out the left axle shaft from an older spare I have, and it is longer but the spline is smaller in diameter as well. It has an even smaller part of the spline length engaged. This convinced me that the shorter axle is part of a later revision, so it is probably correct.

The axle is from a partially restored 220 SE cp I bought. I want to do it right so I am changing wheel bearings all seals, rubber bearing/bushing and the two bronze bushings plus the rubber parts. Of course it will get POR15 treatment at the end so it looks nice also. Only part I will not mess with, is the differential itself.

I will do the same with the front end when the time comes, new king pins etc., etc.

Regards,
Karsten

I see.
The best part to change while the diff is out is the collar/bush in the bottom of the hanger mount. [ the one that the pivot pin goes through.] This is usually eaten away from oil leakageof a bad pinion seal.A very important trick here is to make sure the hanger is at 90 degrees in relation to the left axle casing before tightening the cinch bolts. This is imperative because that is a suspension flex joint that travels through the same arc and the right angle puts it at No load/ neutral position..
The other mount that usually is bad is the trunk support.. This should stick up at least 1/4" above the frame washer . if the washer is hitting the frame , the mount has collapsed..

Yes I have a new "collar/bush" waiting to be installed, The old one was in very poor shape, so were the bronze bushings in the right axle half. BTW, the hanger makes a perfect support when pressing out the bronze bushings, as if it were designed for it.

The trunk mount has likely been replaced, since it looks okay. I have a new one, just in case. It will also have a brand new hydro pneumatic compensator spring. I have not yet driven in a car with such one, so it will be fun to try.

I'll make sure the hanger is 90 degrees in relation to the left axle casing before tightening the cinch bolts, thanks for the hint.

These cars drive so nice when all the ageing issues with suspension and steering are eliminated.

Karsten

Looks like you have a good handle on everything.
Don't forget to center the axle with the cross strut when you get everything back in.
The offset spec on that chassis is the C/L of the pivot pin to be 36mm to the right of chassis C/L..+/- 2mm.
You can eyeball it , and it is important before attempting to align the car.
Good Luck .

Well, I try to do my home work before pulling anything apart. Drive pinion seal is next. Jet another special tool to manufacture in order to get the grooved nut off and to tighten it again with the correct torque. I have a new spacer sleeve and I will remember to mark the position of the joint flange. I just hope that the contact surfage for the seal is not in too bad shape.

Regards,
Karsten

http://www.samstagsales.com/SirTool/stm_0030.jpg

I have made them using thick iron pipe.

They are really on there , so I bought the tool

There are 2 ways to do the seal nut tightening
One is just to index the old set-up, or you can actually set the bearings load
to spec .. I prefer that as the index only gets you where it was and does not allow for wear. If you decide on the later, the turning force needed for proper load is 24/26 in/lbs. You have a new crush sleeve , so if you go to far ,that has to be renewed. Very small increments on the nut [1/8"] at a time and you will not cruch the sleeve past spec.
They also allow for a slight cut on the flange for renew , if it is worn . Many
guys just position the seal a hair out so it rides on a new section of the flange.
It is usually a long term bad seal that causes the hanger lower mount rubber to get eaten away....

Thanks for the link to the tool, I might eventually get that one and a few other I need. Also thanks for the further hints.

Mercedes states that machining the flange is an "emergency operation". moving the seal slightly outwards might work as well.

I also have to redo the oil return thread patterns on the pinion and axle shafts, I guess this should be fairly easy to do. The axle shafts has no signs of these left.

As for the wheel bearings, I ordered the correct roller bearing, unfortunately I discovered that I also have to get the "280 type" brake calibers since the "250 type" cannot take up the slightly higher play in the roller bearing.

I got the rear axle without brake calibers, so I just asumed that I would need the 250 type.

Funny enough Mercedes seems to have used both roller and ball bearings, on the right side, for the exact same model cars, only a few weekes apart in production date.

Regards,
Karsten

Well, I did the tool for the pinion anyway. I found a fitting in the plumbing box which looked good.

To get the geometry right, I did an epoxy cast of the grooved nut:

Epoxy cast

I used a hack saw guided by the epoxy and took the rough part with an angle grinder:

In the rough

The final part was done with a file:

Finished tool

The fit is pretty perfect actually..

Regards,
Karsten