Front wheel bearings on many MBs including the 126 body are the same type as Chevrolets.
One of my first lessons in finance/selling parts came with wheel bearings. In the case of 126 bodies these are, by standard, "Set3" and "Set5" front wheel bearings. After leaving the MB dealer I found I could buy $30 MB bearings for 15 from the local parts store and I marked them up 65% and sold them for 24.75, giving my customer a break. After about a year I found out about Direct Importers and found I could now buy the bearing for $4 from the exact manufacturer as from the MB dealer. Now I am faced with the moral dilemma: do I keep my same mark-up at 65% and sell the product for $6.60 and reduce my per part profit from $9.75 to 2.60.
My shop pays out $14,000 in labor expenses every week. We average about 14,500 labor billed a week. We pay our bills out of parts profit. I still sell that bearing considerable less than MB would and now know where to buy the exact bearing to make unconscienctiousable profit.
As to the adjustment. Mike has the concept, just a little less tight than too tight (bg). My German partner always showed the new guys this trick. Put the tire on and torque it. Take the spanner in one hand and use the other as a fist to lightly pound the tire. If you do this while loose you will distinctly notice a rattle sound that goes away when the nut is tight. The idea was to tap on the tire as one overtightens by a quarter turn to seat the bearing. One would then back off half a turn and do the tapping as one found the exact tention that cancels the rattle. Works pretty good. I always error loose, watch how much you are moving the pinch nut. If you can feel play with the tire on then its too loose. Doing this with the tire on improves ones sensitivity to the play whichever way one is observing it.
Bosch Master, ASE Master, L1
33 years MB technician