I was successful in advancing the brushes on my ADC FB1-4001 Motor. I started with this drawing:
I cut out the image of the tail end of the motor. I overlayed an approximation of my existing mounts on the image. Then, I rotated the image 20 degrees and drew an approximate image of the plate I would need.
In the above image, the existing mount is blue and the new plate is red. One weekend I cut out the plate and painted it. The plate is 1/8″ steel. I cut it with a Sawsall with a metal cutting blade. I drilled the holes with my cordless drill and a lot of oil.
The next weekend, I put it in place on the car. I had to take out all the batteries so I could get at the top and at the bottom of the motor. I supported the motor with a floor jack and unbolted the mounts. I loosened up the 4 bolts that hold the end housing to the motor. I disconnected my A2/S2 jumper. I was able to easily rotate the end housing until the bolts lined up with the alternate set of holes. Then I tightened the housing bolts into the new holes.
After that, I put my new plate in. All the holes lined up! I bolted the plate to the motor and I bolted the existing mounts to the plate. I had to hold nuts between the mount bolts and the plate to attach the existing mounts.
Now, I’m driving with my voltage limit set up to 150V. Performace is a lot better. I don’t notice a huge difference in range. I’m planning on replacing my brushes with new ones from Helwig Carbon since some of the existing ones were a little crumbly.