Heater Fan Motor Demystified
Part 3...
Looking down inside the lower half you can see the bearing and the windings. Everything looked good so I reassembled the motor, put a little lube on the bearing surfaces. The motor spins more freely now.
It looks like if the bushings are worn out, the 3 rivets would need the be removed, and the bearing retainer removed and replaced.
I suspect the windings can be removed as well, there are some positive stops on the side, but I did not want to do any damage to the motor so I did not try. A professional shop would have the proper tools and presses to do that.
From what I saw there is not much I could replace myself, the brushes, cleaning, polishing, and lubing would be about it.
Hooked the fan up to the car battery.
When it first started it pulled 4.1 amps but slowly sped up and finally got to 3.2 amps. The lube on the bushings probably got spread and the bushings may have heated up and expanded a bit.
I was able to confirm a long held belief that a fan cavitating draws less current than when it's moving air, and a baffle in front of the inlet to the fan, even 2 inches away reduces it's output noticibly