Why did I have to force my outer bearing on--'85 300D
 

I replaced the passenger side spindle on my 85 300D. Last week, I siezed a bearing on that spindle. The new bearing I put on in January before this one also failed. ( I had 2 new bearing failures on that spindle--II think the spindle was damaged when my brother hit a curb going 40 mph last December and then drove it 300 more miles and wore out two tires )
I used the spindle from an 80 Gas 280. The part number is the same as the one from an 85 300D. I got it at a junk yard.
I bought a new bearings Kit from Mercedes, but it wasnt in the usual white box with blue stripes.
After I replaced the bearing races I put the Disk Hub back on. I packed the hub with a lot of grease. I noticed it really took a lot of force to push the outer bearing on the spindle! I am concerned. I had to whack the outer bearing in place with a big socket and a hammer. Then I had to wrench the outside C-nut to finally get the bearing in place

Because I have had two bearing failures, I have lost my confidence about what is usually a simple repair. Why did I have to whack the bearing into place?

Is this repair safe? The hub spins freely enough. I still wont driven the car until I get someone's opinion.


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Did you polish the 'new' spindle surfaces to a gleam first? Any minute varnish layer or rusty crud will screw up the bearing mating surface, and could lead to a cracked race. Additionally, the spindle is supposed to conduct heat away from the bearing, which is won't do well if metal/metal contact is poor. Rust happens in a junkyard.

Steve

Carrameow, two things in your post worry me.

One is that you mention "whaking" the bearing in place. Bearings must be installed in such a manner that no force is transmitted through the race path surfaces and rolling elements. Otherwise you get a brinell condition that leads to early failure. A tech that works with me did that to the bearings on his car.... now he has to do the job all over again - this time using a press!

Secondly, you mention that a lot of grease was packed in. You have to play "goldilocks" when packing grease.... not too much, not too little, but just right. Too much grease interferes with heat transfer and proper movement within the bearing during use. That's why Mercedes specifies the amount of grease by weight during recharging. Most bearing manufacturers have limits (both how much and how little) to the amount of grease that goes into a bearing.

Sbourg brought up a good point where the surfaces can't have any burrs, scars, or deposits on the mounting surfaces. A good surface makes mounting much easier and less traumatic to the bearing.

Don't lose confidence in bearing maintenance.... have respect for it. Bearings are one product that needs to be pretty much perfect in the car.

Replacing Bearing
 

All I can say is...OH MAN

I have not replaced a Mercedes bearing,however, I have years of experience with other make, models and the principal IS the same.

With that said, the question that comes to mind is, how are you ever going to REMOVE the bearing, since it was pounded on? OH MAN!

something is not right that outer bearing should slide on with simple thumb pressure,maybe the spindle is slightly oversize being from a different model .or bearing is faulted and undersized that seem like only possibilities if you cleaned spindle well.........
William Rogers......