I am working on my 1990 300CE.
In order to replace the cracked flex discs on both
end of the universal shaft, I gently pulled the
shaft on the rear of the car after loosening the
bracket that holds the center bearing.
I was surprised that the gear spline detached
from the second half of the shaft (transmission side).
I had marked the alignment of the two shafts so that
I can put them back together the same way. I did not
loosen the clamping nut as I did have the wrench that
would fit on that nut, I think it is larger than 34mm.
Is that typical for the two halves of the shaft to separate
that way?
Also, I need to renew the torn rubber sleeve and possibly the
center bearing while it is out.
How difficult it is to replace the center bearing?
When I put it back together, do I need to tighten the
clamping nut which I did not loosen to begin with or just
leave it alone?
Barry Shah
1990 300CE
bshah@satx.rr.com

Yes, you should tighten the clamping nut after everything is secure in its place. You do not want the shaft in tension or compression but you do want it tight.