Rear Axle Pivot Pin - order of assembly?

[jameshoward]

I am in the middle of a change from a 4,08 to a 3,46. The myriad questions are detailed in a separate thread, and there are many like it on the forum.

I have struggled with the information available to me on putting the rear diff back together some 3 years after I took it apart. Neither the BBB pics, the EPC or Haynes have very clear pictures that I can find. The main challenge in the order of the multiple thin steel washers, thick steel washers, bronze washer and O rings go when joining the 2 axle arms together and putting the pivot pin back in.

I've photographed what I think is the correct order having searched for all available info and having had a good look at the axle I took off my car. If anyone can verify this info, that would be great. I'll wait a bit before putting the axle together in case anyone can help with the detail.

Here's how I think it goes in pictures.

The first pic shows the rear of the pin. The order here going forward is: circlip (not shown); large steel washer with curved shoulders, followed by a thin steel washer. The rubber O ring sits over the steel washer, rather than in between.

The second pic shows where the two bronze washers come in (they have 4 grooves in them, presumably to allow grease to lubricate the surface of the axle tube where washer and tube meet. The bronze washers abut the insides of the axle arm. Of course when this is together, the other axle half with the diff on it would be between the yoke.

The third picture shows the large diff hanger/strut bush. In between this and the forward edge of the yoke is a thin steel washer and a thick steel washer. The rubber O ring sits over the this steel washer.

The final picture shows the diff arm bush flush with the arm. I assume that this is the way it's supposed to be, and that adjustment is achieved by moving the arm up and down the bush until the measurement 'a' is achieved (BBB, Haynes, etc refer).

If anyone can confirm or deny this order, I'd be grateful.

James

[tel76]

On the first picture the large/thick washer with the taper goes the other way around so that the rubber washer will make a seal.
I will check the other items tomorrow.
If you can wait I will try to get a picture of the bracket that is (badly) welded to the frame(the axle is not fitted)it is in the correct position, just badly fitted by  the previous
repairer.
Eric,
PS With regard to your search for a new RHS  bearing, when I bought one a few months ago I checked with the usual suppliers and found that when you get your discount off and delivery to your MB stealer the MB bearing was cheaper.

[jameshoward]

Hi, ERic,

Thanks. Yes, quite right about the first washer. Well spotted. It kept falling off as I was messing around trying to steady things for my 'photo shoot. I have put it on the wrong way around 

Any pics would be brilliant.

Thanks.

[Rick007]

Hi James ,

Did the job myself 3 years ago and its all in how you load up the washers and rubbers before you slide the connecting rod into place .
The trick is to stretch the rubbers over the metal to stay out of your way whenn connecting both axle-halves
Btw have you replaced the brass buschings as well ? and did you reamed them to size ? 

Ask Naj he helped me with pictures that explaines more  words ..

Oh.... and watch out the connecting rod is easely messed  up !!      i know by experience and had to buy a new one after first try .

Gr. Rick
 

[jameshoward]

Hi, Rick,

Good to hear from you.

If you mean the bushings in the yoke where the pin passes through, I haven't replaced those, as they look fine and seem ok.

Can you please explain how you screwed up the connecting rod? Mine is fully undone and ready to go back together again. I intend to set this where it was when I took it off the old axle and go from there. It should move pretty freely but I'd be grateful if you could tell me of any problems I'm about to face!!

Thanks,

James

[George Des]

I did this same job a few years back on a spare axle I have. There is a sequence to putting this back together but I can't quite remember it exactly. In my case, I replaced the bronze bearings and that turned out to be an ordeal for a number of reasons. The bearings were removed easily enough and I had an adjustable reamer to size them properly. The ordeal was getting the pin through them without mushrooming the end of the pin. In the end, this was greatly facilitated by setting the pin down in some dry ice for about a half hour or so in order to shrink it to the point that it slipped right through the bearings.

George

[George Des]

Regarding my last post. The portion of the bearing where I had an issue is part#161 on the SLS website. There are two of these on the pin. These portions of the bearings are a shrink fit on the large pin and ride in the bearing shells part#153 which is the part that needs to be reamed. I suppose you can press the pin through these bearings, but the axle is very awkward to handle at the point where the pin needs to be inserted. My early attempts were done with a hammer to drive the pin through and this was a big mistake because the pin end is relatively soft and mushroomed to the point it was not usable. The dry ice on the pin made this a piece of cake to do. Hope this makes sense.

George

[jameshoward]

Hi, George,

I have read of your exploits and refer back to your posts a lot. I can see why #161 was a pain. I'm facing the same issue, albeit without anywhere to find dry ice in Germany! (Found a place in Holland, though). Those sleeves look to be the biggest pain. I'm not looking forward to it at all. I've prepared everything else and it slots together nicely. Expect the sleeves.

Thanks,

James

[Tom Colitt]

Hi James

Just a quick word from me as I am busy working on one of your countryman's work of art, an XJS. There is a quite good diagram in the BBB, fig. 35-5/5. Also, 35-5/4, but there is a small sequence error in that one. You're better off following the sequence shown in the bottom drawing. This means that the grooved washers (10a and b) make contact with the outer faces of the right hand axle carrier and not the inner faces as you show in your pictures. The steel washers 13 a and b go between the inner faces and the machined faces of the differential housing. You guys already caught that the chamfer on the washers faces the o-ring/ sealing ring. Also, remember to align the pin so that you have a chance of hammering in the retaining wedge once the two axle halves are assembled. Also, adjust that distance a =158 =/- 1mm from the diff flange to the rear axle carrier (figure 35-5/8) with the axle out and then tighten it to the rubber bushing so that the the axle carrier and the differential housing form a 90 degree angle (i.e. the differential sits horizontally in the car without twisting the hell out of that rubber bushing before the axle has even gone through it's arc.

As far as I know the only good place to get that barrel type rear axle shaft bearing anymore, is from MB. It does make a difference in longevity compared to just a pivoting ball bearing. Also, you can often get away with not replacing the bronze bushings, but the steel sleeves (11a and b) are almost always worn through the chrome layer and not expensive or hard to replace.

Good Luck. I just did this job for a customer, all by myself and it is not an easy or small task. It helps to have someone to help you guide the finished assembly into place under the car while you're attaching the rubber cushions and aluminum rear cross link/ strut (with the compensating spring already installed, but preferably after the rear axle has already been lifted over the exhaust system, unless you completely removed that.)

Good Luck, Tom Colitt

[jameshoward]

Thanks, Tom. That's very helpful. Hope the Jag AC doesn't catch fire. (Presumably its made by Lucas?)

I have two BBBs. Neither have 35/5. How typical.

If anyone has an electronic copy of that job or could scan the pics Tom mentioned I'd be most grateful. Hoping to put the thing together tomorrow 

(If too big to post here my email is pagoda230@gmail.com.)

James

[Tom Colitt]

The pictures are on page 35-5/2. You'll find them after the other suspension pages.... If, not I'll scan them....

[jameshoward]

For some reason, neither of my books have 35/5. They both jump to 38. (Passenger cars from 1959). Both are complete, but don't have that damned section. If you could scan, it'd be a huge help.

I'm quite keen only to do this once!

Cheers,

James

[jameshoward]

I think I've found the job 35/5!!

Here's what it seems to be

[66andBlue]

Hi James,
just wanted to mail you the same pages! 
As you probably noticed these pages are NOT in the BBB for cars starting 1959 but in the later one for cars starting in 1968.

[jameshoward]

Alfred,

Thank you. I'm such a moron. After posting my reply to Tom, I just googled Mercedes 35/5 and there it was. Does that appear to be the correct section?

Thanks also for the info on clips. I've ordered a bespoke set and will send you some pics. Not sure what the price will be but perhaps I can get them to make up a bunch of clips if folk want them, having finally discovered a useful contact in the company. Hope they fit!

James

[George Des]

James,

Dry Ice worked particularly well on the pin because it brings the temp down quite a bit. I was amazed at how the pin actually vibrated as the temp came down and was able to slip right through the sleeves. You may be able to get away with putting the pin in a very deep freeze refrigerator or perhaps even a few shots from a can of a/c refrigerant. Anything to get the pin really cold to shrink it. Dry Ice is relatively easy to find here since some supermarkets sell it so that carbonated beverages can be made at home. Not sure why anyone would want to do that since it is so much easier to just buy beverages off the shelf but glad they do. I've had to use it for several jobs like this and I know some machine shops use it to shrink fit valve guides into aluminum heads and such. Good luck with this job. It really challenges the mind to figure out how to best accomplish it.

George

[Tom Colitt]

Hi James. Yes, the figures you found are correct and it should be clear to you now? I think you really only had the compensating washers and the brass washers switched. Sometimes you can also look at how the parts are worn into each other to determine how they were together. Good luck...

[Rick007]

I can see you already got the help you need James .
Like I said Naj helped me with pictures and that made things clear for me . The replacement of the brass bushings itself was not complicated but reaming them to size and fitting the pin was . Well to me it was .
Heard then that al lot of guys used a pointed guiding pin to keep the rivets and rubbers align . I tried that with my ruined pivot pin ( mushroom on the end ) but in the end a long threaded rod with a couple of bolts did the trick .
Hope it works out for you because after the job is don you will be rewarded ( depending on how far your axle was gone ) with a transformed car.

Gr. Rick