I have 112,xxx miles on the E320 and have replaced everything that is driven by the serpentine belt on the front of the engine except the air pump (air pump pulley with bearing was replaced), the power steering pump and the air conditioning compressor. I do not think it would be worthwhile to just try to replace the bearing on the fan bracket. I will see if I still have the old one and maybe dissect it to see if the bearing replacement is possible. I replaced the radiator at the same time as the water pump. The water pump and alternator failed was the reason they were replaced.
I plan on changing the water pump and radiator on the Honda between 100k and 110k.

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Jim