New Drive shaft center support bearing. Fits all 240D, 300D, 300CD, 300TD, 300SD 300SDL 300CE 300E 420SEL 380SE 280SL 450SL 560SL, gasoline and diesel models from 1968 to 1993. This bearing may need replacing on high mileage cars.
The only way to test the bearing is to remove or drop the drive shaft down so you can manually spin the bearing. If it is smooth and quiet you do not need to replace it. If it makes any noise at all change it before it goes bad out on the road. This bearing is a press fit on the long section of the drive line. You may been a special puller to remove it. Most machine shops will be able to remove the old bearing and install the new one if you take it to them. Replace the rubber bearing carrier at the same time. Look below to order.
WARNING: If you plan to split apart your two piece drive shaft you MUST make certain it goes back together in the same position before you took it apart (the driveline is balanced at the factory with both halves together). You can mark the two half's with a paint line for alignment reference at reassembly.
With the driveshaft out you can also check the smoothness and tightness of the universal joint. I have seen these joints last over 500,000 miles so it is not common for this universal to go bad. If you feel any slop in it I would recommend you find a good used complete drive shaft. Changing the universal joint is not easy and will require you to rebalance the driveshaft when done.