problems with refurbishing rear axle 4,08 to 3.25

[Rodolfo]

I have a 230 sl 66. manual.
Today I rebuilded the differential (4.08 to 3.25 and all new bearings). There was not a problem, normal mechanical work, which was rather straight forward. Also thanks to great advices here.

But:

I also had a broken U-joint/slider on the right rear axle (actually the main reason why I opened the rear axle).


After a long search, I finally  found a shop which had a U-joint for sale.The seller told it was new. (not so cheap as a result). I bought it.

Now I have two questions:

1) is this U-joint normally with the inner slide included? So I should have it with a new slide in it?

2) for the moment I use the so called new joint, and was taking the slider out of my old, to build it into the new joint.
Also there was a breakage in the inner-slider, it seems. See photo. Is this slider seperate for sale, or always included in the joint normally?

best regards,Rudy

[jeffc280sl]

Hi Rudy,

Congratulations for making the decision to convert to the 3,27 ratio rear axle.  I did the same 5 years ago and I'm very pleased with the outcome.  I purchased 2 used complete 3,27 rear axles as donors.  They both turned out to be fully functional so I sold one to a member here.  Unfortunately I did not separately purchase the part you need.  In fact I didn't dismantle the donor axles to the point where I could see this part.  I simply used the complete U-joints which included the slider piece.  Sorry I don't have the answer you seek.

[ctaylor738]

According to the EPC, the slider is PN 110 350 00 48, available for $260 list.  This is for cars as of ID 014750.  NLA for older cars.

My congrats also for taking this on.

Cheers,

CT

[Rodolfo]

my car is 113 042 10 0015364 so that should be right then?

PS Taking on the diff was a smoother job then I expected. Everything inside was very healthy there. But I changed all bearings as well.  The 3.27 pinion and gear- kit was fitting perfect. Now my  only problem is with that slider.

[jeffc280sl]

Hi Rudy,

Glad the donor axle was good inside.  I found both of the ones I purchased to be very robust.  I changed outer wheel bearings as well.  Did not replace pinion gear bearings.  I also installed a new axle hanger and trailing arm bushings.

[ctaylor738]

Yes, according to the EPC, that part will work in your car.  You should be able to order it through your local dealer.

[Rodolfo]

Chuck, thanks a lot. I will check with the Mercedes dealer.

Jeff, thanks for the encouragement.

best regards, Rudy

PS I didn't actually used donor parts, but purchased new gears and bearings. A complete donor subassembly would have been ok, but gears or bearings which are used, I don't combine in another setup. A complete used rear axle I would use. In my opinion used gears or bearings are worn in to each other in that particular casing and not so advisable used in a new combination. At least not for long term trouble free use.

[jeffc280sl]

Hi Rudy,

I have no experience with an old axle hosting a n we gear set.  Hope it goes well.  Carefully with the crush sleeve alignment tool go on pin and ring gear..

[naniroma0]

hola Rodolfo,
yo estoy interesado en hacer la conversion a 3,25
donde  ha comprado el piñon y la corona? y cual es su metodo de ajuste?
saludos.

 Hi Rodolfo,
I'm interested in doing the conversion to 3.25
where you purchased the pinion and gear kit (crown)? and what is your method of adjustment?
Greetings.

[Rodolfo]

I guess I also need to change the crush sleeve between the pinion bearings.
Anyone knows the partnumber of this?

It is a 230sl from 1966 with VIN 113042 10 0015364

[George Des]

If you are switching out the pinion and crown gear, you will most definitely need to do the crush sleeve. This is required to set the spec pre-load on the two bearings that the pinion rides on. Be careful when ordering the crush sleeve as they are not all the same amongst the differing axles. I know the axles used on the 230SL stock rear ends are of a different design from those used on the later models. Also, be aware that a number of adjustments using shims need to be made to get the correct mesh between the pinion and crown gear as well as the correct set back. I'm not entirely clear from some of the manuals I have read on this how to do it properly and I'm sure this is a big reason why a lot of us shy away from doing any rear axle work that gets into this. My understanding is that if not done properly, you will have noise from the rear end and possibly gear failure. I have talked to some mechanics who have done this work on American built rear axles and they have said it is pretty straightforward but that the MB rear is of a much different design which makes the adjustments more problematic. Perhaps Dan, Gernold and Joe A can better fill you in on the particulars of how to do it correctly. Not trying to scare you, but you should be aware of all the potential minefields before taking on a total gear replacement--it's not just a remove and replace proposition.

Good Luck and let us know how it goes

George

[Rodolfo]

Hi George,

I am aware of the need to change the crush sleeve. But I don't have the Mercedes partnumber. I hope somebody could help me with that.

best regars, Rudy

[mbzse]

.../... I don't have the Mercedes partnumber. I hope somebody could help me with that

Rudy,
The most efficient step for you is to be member of a M-B club acknowledged my M-B Classic. You then have access to the EPC online, with all part No.s for your car. Discussed several times here on our Forum.
See Peter´s posting http://www.sl113.org/forums/index.php?topic=19656.0.
If you do not want to go that route, there is a company called SLS in Hamburg who have a good website. You go in on page 35a and there you have your part, complete with the M-B part No. SLS do not supply that part themselves, obtain it from a M-B dealer.
/Hans in Sweden
.

[Rodolfo]

A parts dealer refers to it is item 96 in the Epc. Is that correct ?

Would really appreciate confirmation since I don't have access to that.

Rudy

[Rodolfo]

As for today I now have all the parts. In the mean time I cleaned the rear axle and repainted all in satin Black, looks nice.

Now I have to setup the pinion, with a new crush sleeve  and bearings I have. What is the torque I should use for this?

best regards Rudy

[Rodolfo]

Reading through the forum I don't find torque for the pinion nut. Seems I need to measure the friction torque of this shaft while rotating  it. This makes good sense: then you measure the result. And you are not depended anymore of the axial resistance of the bearing to move (which would differ between different shaft, bearing combinations). Right ?

Rudy

[George Des]

Yes, it is the friction torque you need to measure. Best to creep up on this value cro the lower end of the torque range.If you over torque you need to start all over again with a new crush sleeve.

[Rodolfo]

Thanks George,  for the affirmation.

Today I assembled the pinion axle without a crush sleeve in between the bearings, to find out where the " touching point" of the bearings would be. I measured then how deep the nut was. So now I will disassemble again and put the new crush sleeve in between the bearings.

What I noticed was that I can only lock the nut on the pinion shaft every 1/4 of a tour. That is a pitty, since at one position the bearings are still a bit loose, but 1/4 further they are to tight. Any suggestion?

best regards, Rudy

[Rodolfo]

Pinion and U-joint problems all solved now. I started to reassemble the rear axle.

Question:

1) now was a 14 mm hexagon bolt used for the u-joint. It is a bit hit (head not straight anymore ). I will look tomorrow to find another. In case I don't find an original hexganon, is an Allen bolt M8 completely exchangeable with the hexagon?

best regards, Rudy

[George Des]

I have seen both type bolts used in this application. Not sure which one is stock though

[tel76]

How did you get the pre-load on the diff: carrier bearings correct and did you use engineers blue to ensure you have the correct mesh

[Rodolfo]

I used a alcohol based marker, since I had no engineers blue.

I needed to shim an additional 0.2 mm behind the right bearing (to have play around 0.16 mm). The left bearing I did on feel with the big nut. It is now slightly different then before (two openings further) Have no idea about torque for that.

best regards, Rudy

[GGR]

Quite an involved job! What method did you use to take the left bearing race out of the wheel tube? Where did you get the shim(s)? Nice job!

[Rodolfo]

The shims are very cheap to get where they sell bearings. Standard 63-80 mm can be bought at different thicknesses.

For the left bearing race I made a small plate which I could block behind the race and then I knocked it out through the tube hitting on that small plate.

Problem today:

I was reassembling the rear axle, after closing the differential. When I putted the U-joint with an Allen bolt to the differential right side I noticed a bit of grinding when I turned the U-joint. First I thought the U-joint was touching the big nut. It wasn't. So I reopened the differential again to have a closer look. Seems nothing wrong with the new bearings or the pinion and big gear of the pumpkin. It are the small gears in the pumpkin . To be more specific: the small gear (right side of the car) where you bolt the U-joint onto, has some axial play of about 1 mm (all the three other gears seem to be fine). Also no problems with the pins on the small gears. I placed some photos.

1) should there be no axial play?
2) these small gears of course only turn in corners, but it should be repaired? Or am I worrying to much about that?
3) could that small axle been pushed a bit inside, when placing the right inner bearing?
4) how can I retract that small axle? How is it axial connected? Any rings there?
5) anybody has a cross section drawing of this?

thanks in advance



Rudy

 (I am a bit dissapointed, I thought I was through the problems)

[GGR]

You should not have any play there. I saw that once on a 6.3 and for some reason the side differential pinion had eaten the cavity in the diff carrier it slides in. I would personally not put back a differential in that condition. You need to take the crown out and then the center pin out. You will then be able to get the two differential gears that were held by the pin out. After that, you will be able to take the side differential pinions out one by one, by pushig them towards the center and then sliding them out through the opening in the diff carrier. You will then have to inspect all the parts for damage and wear. Your carrier will most likely be damaged. I guess it could be repaired by sleeving it. Replacing it by a good used one may be more cost effective, especially if you get a complete diff unit, as other parts of yours may also be damaged.   

Also, the bearing and that pinion are not connected, apart from the carrier itself with the lip for the bearing on one side and the cavity for the pinion on the other side. Apart from braking the carrier itself, pushing the bearing into place will not affect the position of the pinion. I don't remember any shims behind the side pinions. Play is controlled by plastic shims on top of the other two pinions held by the center shaft. You may have to replace these plastic shims by new ones.