Tech help required: are there tolerances for rear wheel play?

[jameshoward]

Evening all,

We've now moved back to Germany, which means that the 230 has to be licensed as safe to drive by the organisation I work for (for insurance reasons, basically). It has failed because there was quite a bit of movement on the right rear wheel. It was not lateral, as such, but was 'in and out.' I have today replaced the bearing with a new one, and whilst the 'in/out' play has gone, I have a very small degree of lateral play.

I am getting the car re-tested tomorrow, and would ideally like to know if there are any stats in the BBB on what is deemed within tolerance for the rear wheels. I imagine that a small degree is permissible, and wondered if there was a section in the BBB that dealt with that kind of info, or whether it has always been done on a best guesstimate basis.

If the car fails, I assume the next step is to strip down the axle again and use some kind of shim. Grateful for any suggestions on where it might go. I assume inside the bearing housing before the bearing is fitted??

For info, the rear axle halves on my car do not have the circlip that later cars have, so I do not think my problem is from an incorrectly seated axle. Given that I intend to fully replace the rear axle with a 3,49 this winter, I have also cheated and used the standard bearing rather than the fancy bearing that costs about 4 times as much. The only mileage the car will be doing on that bearing will be European Event and I think I can live with it being that way for a few months.

Thanks in advance,

James

[Rick007]

Hi James ,

Did my rebuild of the rear axle last year , after the 2010 Event . I noticed a squealing sound going trough a corner , left or right I don't know anymore . It seemed that my right bearing had some play which caused the brakedisk to move slightly in and outwards . After studying our forum and the German forum the ( as you call it )4 times more expensive bearing made sence , so I installed it . No more squeal .
It seems that this bearing catches the lateral movement ...... My advice would be pay the price it's worth it ....and we don't want mis you at the 2012 event .....or worse have to pick you up with a flatbed truck

Gr. Rick

[Benz Dr.]

That right rear bearing is a self aligning type and you really need to use it. Substituting this bearing for the regular ball bearing is not a good idea.
You can damage the slip coupling or the universal joint inside of the axle. The right hand axle moves over center in an arc that requires freedom of movement. Anyone who tries to sell you the regular bearing for this application simply doesn't understand the consequences.

[jameshoward]

Hi Dan,

Hope you're well. Thanks for your post. Rather than just leave this hanging and leave someone else confused, I agree fully with what you write about the requirement for the self-aligning bearing and the geometry of the rear axle and its movements, etc. However, given that I'm changing my axle this winter to a 3,46 (which has 2 of the self-aligning bearings rather than just the one on the 4,08), I think it's an acceptable risk to run a normal bearing for a few months in order, first, to get the car through it's TUV test (now done, thankfully) and do the Euro event. I will be taking it easy on the corners, but the price of the new (correct) bearing on top of everything else meant that this is a risk I'm prepared to take. We'll find out if I was wrong if I have to make a roadside post asking someone to email the part numbers for a new axle tube.

Thanks for pointing out the risks.

James

[stickandrudderman]

Why not fit the correct bearing and then re-use the drive shaft when you swap axles?

[jameshoward]

Why not fit the correct bearing and then re-use the drive shaft when you swap axles?

Extremely sensible. But timing and dispersion of kit as I moved between the UK and Germany conspired against me. I had to get the car through the TUV quickly and only had a small window. Long story. Can't say it's the preferred solution, but at least the car goes!