Shredded rubber seal on rear axle

[blairwag]

In my repair nightmare this weekend, I was attempting to lubricate all grease fittings on the chassis and drive train. When I got to the rear axle I found a seal on a cylindrical "thing-a-ma-jig" that is mounted on the front right side of the differential case. Looking in the BBB, it *LOOKS* like this thing is called "Carrier for rear axle suspension". Here's a picture, taken from the ground, looking up at the bottom of the rear axle/differential assembly, with my feet out the rear of the car. The top of the picture faces toward the front of the car.

Question: what the heck is this thing?

Download Attachment: IMG0512.jpg
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Download Attachment: IMG0511.jpg
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Question: the rubber seal between this cylindrical thing, and the differential seems to be torn up. Do I care about this?  Is it easy/difficult to replace?

...I know, I know, the whole rear axle assembly is nasty with lubricant drippage/seepage.  One thing at a time, I'll get to it! Maybe this seal is my problem?


--
~~~~~~~~~~~~~~~~~~~~~~~~~~~
William Blair Wagner: blairwag@earthlink.net
Education is not always knowing the answer,
...but rather knowing where to look for it!
1971 280SL US Automatic
~~~~~~~~~~~~~~~~~~~~~~~~~~~

[ja17]

Hello again William,


The good news is that most of the rubber bushing is up inside the metal tube, and is probably in decent shape. Oil and grease will attack the exposed rubber over time, so the exposed parts of the bushing deteriorate first. However this is a wake up call and the job will be required in the future. It is a pain.

Joe Alexander
Blacklick, Ohio

[A Dalton]

The problem starts at the pinion seal .. The lube eats the rubber inside the hanger mount. One would think that these have plenty of rubber mass inside , but the originals do not . They are a 2 piece  rubber and are full only on the outer ends .  The center is hollow. The replacement mount has been modified and has the full rubber , so it is that one that is not of concern. One will note that that this is not just a pivot hanger , but also a flex joint for axle pivot/swing. Tne outer and inner points are fixed and the mount flexs with axle swings , making it a working suspension part.
[ For easier expalnation,you can see this in any cross section view]
 An easy quick glance observation on these is to see if the pivot pin bolt eyeballs center with the outer casing of the mount .. if it looks shifted , it is getting bad.. it is always the front section that goes from the leaking seal and drive-line torque.
 The time to change it is when you are doing the seal, as it is not a bad job after the front flange is removed [ which has to be done when doing seal.]
This is done with diff in the car . The pivot pin does
not have to be removed, as the mount will slide off the pin once the pivot pin cinch bolt is loosened and the front bearing/seal plate is taken off the diff.  The seal can then be changed when this piece is off [just easier]
 The main concern on this jub is to either index the flange , nut, and components for re-installing the pinion flange nut, or use the recommended torque measures in the book for pinion bearing pre-load.
 You do not want to over-tighten the pinion flange nut at all cost, cuz if you do, you have to replace the crush sleeve and start all over again.
 I did a section on this in the archieves and should be somewhere in there.. maybe  using 'rear diff change' or such for a search...
I will try and find it ..
 I think it was when Wagas was doing a diff changeout..

[A Dalton]

Found the info .. there is mention of this item and procedures in there..

http://index.php?topic=1642#20257

[blairwag]

I'm confused. Looking in the BBB, it looks like Job No. 35-5 outlines the removal and installation of the "Righthand Supporting Tube with Connecting Bolts and Carrier of Rear Axle Suspension". I'm guessing this cylindrical contraption is holding the rear end assembly in place with the arm that reaches straight up from the top half of this tube?

According to this procedure, I have to take the rear axle off the car. Is the "rear axle" in this text the entire rear-end assembly, or is it just one of the axle shafts? Also, this section talks about the "supporting tube". Is that the huge tube, that stretches from the differential pumpkin to the right wheel, or is the "supporting tube" my cylindrical contraption?

I've read the thread that you (A Dalton) posted, but I'm missing it. Where is this rubber ring replacement described?  Looking at Fig 35-5/3 on BBB pg. 35-5/1, it looks like my rubber seal that's all shredded is part "9a".

Questions:
* Can I replace this rubber seal without taking the rear end off the car?
* Can I replace this seal without taking the right drive shaft out?
* Can I replace this rubber seal by supporting the rear differential pumpkin, and unbolting the huge Hex. bolt (#1 in Fig. 35-5/3), and separating the rear assembly from the Carrier for rear axle, and slip the old seal off and slide a new one on?
* How does the pinion seal play in this? Isn't the Pinion seal the seal behind th yoke on the front of the differential pumpkin, where the drive shaft universal joint mounts?
* Perhaps the pinion seal is what's leaking so much fluid. Are you suggesting I do the pinion seal and this "9a" rubber ring at the same time? Can I do these jobs without major surgery of the rear end?

Well, I guess that pretty much maxes out my quote of questions for the day, ey?

Thanx, gang, for all your help. Your advise and guidance is more than invaluable!


--
~~~~~~~~~~~~~~~~~~~~~~~~~~~
William Blair Wagner: blairwag@earthlink.net
Education is not always knowing the answer,
...but rather knowing where to look for it!
1971 280SL US Automatic
~~~~~~~~~~~~~~~~~~~~~~~~~~~

[A Dalton]

I know  about the BB and their procedure of changing the hanger mount.
 I did not want to cause you confusion, but to merely tell you that if one is changing the pinion seal, it is a good time to change the hanger mount as 1/2 the work has to be done when doing the seal.. this is not a BB procedure .. it is one that I have done on several swings and it is my IN CAR changeout .
  It is simply a way of changing the sleeve mount without having to remove the pivot pin that goes trough the entire rear end  and axle tube swivel point.
It can be done as BB shows , but that is a lot of work.
I do not have the BB pages you use , so I can not reply to your 9a question
 

[George Davis]

William,

I think both Joe and Arthur are saying the rubber part that is shredding is the rear end of part no. 5 (rubber mount) in Figure 35-5/5.  It runs all the way through part no. 6. The BBB shows this rubber mount as being two parts, but if I've followed the discussion correctly, this was updated to a full length one-piece mount at some point.  It's the rear of this rubber mount that seems to be shredding, just in front of part 8a.

Part 9a in Figure 35-5/3 is the same as part 9 (rubber ring) in Fig. 35-5/5, you should be able to see these rubber rings more easily after cleaning off the grease.  I think I can make one out in one of your photos.

Hope that helps some.

George Davis
'69 280 SL Euro manual

[A Dalton]

This is the part referred to.

http://213.239.220.84/bin/dbframes.phtml?mid=IN02
click on picture of rear axle and look at item # 151.
 This is the mount . It slides over the pivot pin and is held to the hanger by 2 cinch bolts. It has an inner casing and an outer casing . Between the casings it is filled with rubber. The new part is the same dimensions as the orig, it is just that the origianal was not rubber filled all the way through..just on each end... so they wore out when oil from a leaking pinion seal eats the rubber..
 I do not have the book pages you refer to , so maybe this will help clear up what I am taking about.

[dwsfca]

William,

I concur with Joe Alexander on this topic.  If you can hold off doing this repair do so as it is a significant project.  I  changed this part along with the rubber hanger/mount (in the trunk) last year and it was quite a job! On the other hand it made a considerable difference in the stability and handeling of the car. While I was at I also replaced the rubber bushings on both ends of the swing arms that attach the axle to the car.

You do not need to remove the axle from the car to replace the main part(the thing-a-ma-jig you describe) but it is an easier job with the axle removed.  Unless you are fairly comfortable with mechanical repairs I would recommend you leave it to a professional.

Good luck
Dan

[waqas]

Hi William,

I couldn't help but chime in here. I recently completed a full axle replacement (my differential was shot), and I replaced practically all the rubber components, including this mount. A.Dalton is right-- you can replace the mount with the differential installed. Referring back to A.Dalton's link (http://213.239.220.84/bin/dbframes.phtml?mid=IN02) and clicking on the picture with the axle:

(1) Disconnect the drive-shaft from the differential flange
(2) Mark the flange and grooved-nut before unscrewing (you need a special tool for uncrewing this-- will post later). Parts #14, #13 in figure.
(3) Remove the front plate from the differential (6 bolts and one cinch bolt).
(4) The pinion seal is part #8, and it mounts into the just-removed front plate (grayed-out in figure, to the right of part #8)
(5) The "shredded" mount is #151. In order to remove this, you need to slide it off the long pin/bolt (#152), and through the carrier (grayed-out, underneath trunk mount #140 in figure). Sliding the mount out while under the car may take some ingenuity, but it is certainly straightforward.
(6) When re-installing the mount and the tightening the cinch bolts on the carrier, it is imperative to make sure the carrier and the left axle are perpendicular to each other. Again, doing this under the car may be a bit tricky.
(7) This might also be a good time to replace the trunk mount itself (#140) if necessary, and perhaps the lateral rod mounts (#114,2x, and #115,2x).
( Re-install the differential front plate, flange, and tighten the grooved-nut according to the original settings (or re-torque the crush bearing setting according to the BBB instructions).

Also, A.Dalton and Joe Alexander provided some invaluable instructions in the thread "Replacing my 230sl differential".

Doing this same job with the differential out of the car is certainly easier, but will take a lot more time. Let us know if you've any questions!

Waqas in Austin, Texas

[blairwag]

Okay, gang,
It's starting to sink in, now.

Joe, Arthur, George, Dan, & Waqas - thank you. Arthur and Waqas, you're descriptions are invaluable. Due to the amount of sludge on the rear end, I *THINK* I've decided to attempt teh job of replacing the rear pinion Seal ring (input shaft, #8 @ SLS web catalog) AND the rear supporting tube slip joint Rubber mount ( #5 in BBB 35-5/4 and #151 @ SLS web catalog). I hope the job isn't too hard. I've got decent mechanical skills and tool set to help through it all.

According to the BBB, and Waqas' last post, I need a special spanner tool to get the groved nut (or slot nut) off the drive pinion in order to remove the universal flange. I've asked Samstag if they have it (I found it at this web page) and asked for a price.
http://www.samstagsales.com/mbref.htm
look for 111 589 00 07 00 on this page.
I also see a "115 589 02 07 00" for USD $64.95. Is this the tool I need?
http://www.samstagsales.com/mercedes.htm#Axle (look for 115 589 02 07 00)
pic: http://www.samstagsales.com/SirTool/stm0027.jpg
...that picture doesn't look right.

Can anyone tell me if this tool, on eBay will work?
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&category=33738&item=7988081941&sspagename=WDVW

Also, in order to get the rubber mount/bush off the pivot pin bolt, do HAVE to take the Carrier of read axle suspension ( greyed part under #140 @ SLS web catalog) off the car? Or is it possible to get the mount out without taking this off the rear subframe trunk mount (#140)?

Thanx for all you help, guys.  You make owning and repair this car possible. Without you all, it would be impossible.


--
~~~~~~~~~~~~~~~~~~~~~~~~~~~
William Blair Wagner: blairwag@earthlink.net
Education is not always knowing the answer,
...but rather knowing where to look for it!
1971 280SL US Automatic
~~~~~~~~~~~~~~~~~~~~~~~~~~~

[A Dalton]

The ebay  one is tranny nut
 The other is axle seal flange nut

 here is the one you need

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

 It is also easier to take the hanger down as you can then take the collar mount out on a bench.
 The tricky part is not the mount, but the pinion shaft flange and seal part of the job. You will need a puller for the pinion flange .. just a standard 3 arm one.
 Any of us can assist you with that part of the job. Just index everthing and read Wagas entire post well.

 ....Maybe Wagas wants to sell his pin socket?

[waqas]

I have strict rules against paying $70 for tools I can easily make (it's in my charter):

1" socket open stock: $2.99
cheapo angle grinder: $8.99
5-pack grinding wheels: $4.99
harbor freight patronage: free
bench vice mounted on plank of wood: (doesn't everyone have one??)
making my own pin-socket-tool-thingy: about 20mins
total: $17 and some care

Rules:
(1) make sure cutting/grinding is with wheel turning away from you
(2) face the back of your lawn, away from people and cars
(3) definitely wear gloves and safety goggles
(4) tie your hair back behind your head  :?  (or wear a hat)

I can send you mine, but making it yourself is far more satisfying (AND, I have a cheapo angle grinder and discs for further mayhem in the garage). I'll post specs later this afternoon.

Waqas in Austin, Texas

[waqas]

Here's my pin socket (the original 1" socket is 3/4" drive, so you might need a socket adapter to fit your torque wrench)

Download Attachment: differential-pin-socket.jpg
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Differential Flange Grooved Nut:
Outer diameter:  35mm
Inner diameter: 24.7mm
'Pin' width: 7.8mm

Transmission Flange Grooved Nut (for your reference):
Outer diameter: 38.8mm
Inner diameter: 33mm
'Pin' width: 5.5mm

It's a bit funny to see the dimensions given to one decimal place, given the 'imperfections' in grinding out the pins. The important thing is that the pins fit the nut, and don't slip out while you're trying to turn the socket.

Waqas in Austin, Texas
(pronounced Wa-kaas, following Cees' example   )

[JimVillers]

Waqas .... A very functional pin wrench.  If you use a hacksaw or a cutoff wheel with a drumal tool, you can get flat sides on the "pins".  I have made a number of similar tools and agree with you, why pay for something you can make in less than an hour froma surplus socket.

Jim Villers
190SL, 230SL 5-Speed, 190E 2.3-16 Kompressor

[blairwag]

Wow - that's cool!  I never even would have considered it.  I've got the dremmel tool, but not an angle grinder. I'll look into it. Thanx!   ...totally cool!


--
~~~~~~~~~~~~~~~~~~~~~~~~~~~
William Blair Wagner: blairwag@earthlink.net
Education is not always knowing the answer,
...but rather knowing where to look for it!
1971 280SL US Automatic
~~~~~~~~~~~~~~~~~~~~~~~~~~~