I pulled out the blower motor on my 1980 300TD. I'm not sure if it is a Bosch unit or not there was no manufacturer name stamped on it. I had to file the staked areas around the rim of the can to get the back cover off. The brushes were well worn so I set about to replace them. They measured 5/16" square and had coil springs behind them. I don't have an ACE hardware store nearby so I went to TrueValue. They had a box labeled carbon brushes but they all were no thicker than 1/4". I ended up with 1/4 x 5/16 brushes each with their own spring. I glued a 1/16 aluminum shim to the bottom side of each brush holder to make up the difference. This was in the width direction so the diametrical contact would be the same. The brush holders are offset by a half 1/2 brush width so a corner of a flat brush face would contact the commutator. Not an idea situation. I have a small milling machine so I cut the brush to get the profile and length right. I also have a lathe so turned the commutator. For some reason it wore into a conical shape and was heavily groved so this really improved things. I had to use the smaller diameter springs that came with the brushes so I cut them to the same length. The spring rates seemed to be about the same. I soaked the bushings in the can and end cover in heated AT fluid for several hours to try and get the porous metal to soak up more oil. I assembled everything back and added some additional shims to take out some end play. When I hooked it up to my 12V power supply it seemed to run faster and quieter than before so I am pretty pleased. We got about a foot of snow today so I have to dig out the car to put the fan back in. I would also like to check out the resistors that control the fan speed can someone tell me were they are located?

Thanks

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Bill Reimels
Now down to one:
1972 300SE 3.5 W109 (Euro delivery)