Rear Right Bearing Lateral Play Elimination

[Pawel66]

Happy New Year, everyone!

Just fixing some of the topics with the car during the winter hybernation period. One of them was too much lateral play in the rear right axle. The bearing was bought from MB, the correct one, new.

I have read on the Formu that the way to eliminate the lateral play is installing the shim - I just wanted to make sure where. My understanding from your posts was that the shim should go between the side of the outer race of the bearing (the bigger, 80mm one) and the race seat in the axle tube.

Is this correct understanding? Please kindly advise.

Best regards,
Pawel 

[Pawel66]

Hello again, everyone,

I would like to kindly request your advice. I was trying to figure out how to help you help me - I am attaching a drawing of a rear wheel hub. It is the left one with ball bearing. I do not have the drawing of the right one.

Please kindly indicate where do I place the shim to get rid of the play: 1, 2, 3 or 4 or "none of the above".

I have a new bearing from MB. I have about 1mm play. I am reading the new bearings have this play. I can buy a new FAG one, but it is the same as MB. I am reading placing this shim is an accpeted method of eliminating the play. I just need to confirm where I should put it.

Pawel

[Benz Dr.]

I've found a certain amount of end play even in new barrel roller bearings and it may even be needed to make it function properly, so I'm going to say it's probably normal. End play can not be eliminated at the outer bearing race if movement is present at the rollers. My dealer's parts book shows no shim available and I've never installed one during any of my rebuilds. The brake anchor, or backing plate, presses against the outer race of the bearing and that's all that keeps it tight from what I can see.
 
The left side is a ball bearing and any end play on that side should be considered suspect. This may seem like conflicting information but we are talking about two very different parts doing similar yet very different jobs.

[ja17]

Yes, I also have not ever used shims on the axle bearing. The bearing should be a tight fit in the axle tube. Once installed it should not be able to move laterally. Possibly your axle tube is worn oversize from a previous failed bearing "spinning-in-place". Some punch marks in the housing and Loctite stud and bearing mount, should tighten everything up.

[Pawel66]

Ok, thank you for your voices there.

We will definitely remove the bearing (I do not have a neither circlip nor groove for it on the right axleshaft, so we can refit it in a civilised way) and examine it for turning - if this is the case, we will go the punch exercise. We will also make sure that the nut is properly tightened.

I went through several posts on this play in the right bearing and it looks like quite common issue. The solutions were: nut tightened, punch exercise and... this shim as described "between the outer bearing race and the wheel tube". And this shim solution was said to come from Mercedes manual.

Truth is also that someone provided the specs for this bearing that said the lateral play on barrels is 0,7mm.

Ok, thank you again! I will try the new bearing, ensure fit in the housing and on the axle with punch and Loctite and proper tightening of nut. We will see where it takes us.

Regards,
Pawel

[Benz Dr.]

I don't think I'd lock tight the bearing in place and if it's that loose going on I'd be looking for a used axle shaft. The bearing goes on with an interference fit ( pressed on ) and it should take a bit of effort to  knock it into place.  It should never slide on.

[Pawel66]

Ok, thank you, I think I understand how it should work - thank you for your kind help!

[ja17]

The punch and Locktite trick works well if your axle housing is worn. Only use the method if your housing is worn too loose to hold the bearing tight. The Locktite stud and bearing mount is made exactly for that purpose. Of coarse if time and cost is no concern, go for replacing it.

[Pawel66]

Thank you, Joe!

Of course money is always an issue as there is never enough of it! 

We took the bearing out. It had some traces of turning in the housing, it went out of the housing with some effort, but not with a lot of effort - we will go through the punch exercise.

But the most astonishing was the play on barrells - felt like very loose (a new one from MB). Yes, I am ordering a new one from FAG (20208). I preferred not to go for the double ball bearing (1208) as it was not really advised on this forum to do so due to lower load parameters.

pawel

[Benz Dr.]

The punch and Locktite trick works well if your axle housing is worn. Only use the method if your housing is worn too loose to hold the bearing tight. The Locktite stud and bearing mount is made exactly for that purpose. Of coarse if time and cost is no concern, go for replacing it.

I guess I missed that. You're talking about the housing in the axle tube and I'm talking about the axle shaft which are two very different components. In the case of the axle tube, I can see where only a small amount of tightening would be required. Ordinarily, the outer flange should hold the outer race tightly enough that it wouldn't turn, or at least very slowly if it did. I use displaced metal tightening to fix loose distributor parts so I'm familiar with the process.

Maybe I need to wear my glasses more often......... if I could only find them....

[Pawel66]

Maybe you have your glasses on your nose while you are looking for them.
In my country there is a little poem for kids about a gentleman who was looking for his glasses and found them finally on his nose .

[ja17]

I like your terminology Dan, (displaced metal tightening).

[Pawel66]

Just to close the topic: I bought a FAG bearing without C3 description (tighter), we went through the punch marking exercise (or metal displacement technique if you will - but it sounds more expensive ), we fitted the FAG bearing I bought and there is no play.

Thank you for your kind assistance!

By the way: I was calculating forces to check if the 1208 (double roller) bearing would work. If you take this force equasion (for dynamic load): Fr=mv^2/2, then F=mv^2/2r, if we take m=250kg, v=50km/h or 14m/s with r, say 10cm (for suspension to give in), then we are arriving at F=245kN. The bearing 20208 (which we use) has dynamic load of ca 50kN, the 1208 has 20kN. Now: the formula is probably wrong for a rolling object (such as the wheel is, this formula is for the force of a hammer hitting something) plus there is a suspension spring with shock absorber and they abosrb most of the load, but as speed is in square - we would anyway get a very high value of the force. So this tells me - better stay with a stronger bearing....

Pawel

[stickandrudderman]

I've fitted several 1208 and not had a problem yet.

[Pawel66]

Yes, I know, I have read about it. This was just my choice.