Decided to service air pump bearing on 1992 300TE with about 148K miles, before it got noisey or failed completely. I removed bearing from pulley, removed seals with proper size and shaped pick, cleaned, regrease and reinstall.
I did the same to the bearing on my 1992 300E with about 137K miles on it a few weeks ago. I was going to install a new bearing but since I could not find one locally, just did the same as I stated above. The bearing in the 300E was very noisy and stiff. I don't know how long my servicing of that bearing will last.
Second photo is with seals reinstalled.