Coaster Brake Rebuild/Repair
I followed Steve Litt's disassembly instructions, cleaned the parts in brake cleaner, and did my troubleshooting. The first problem was, of course, to determine just how the hub/coaster brake worked, then I could determine why the problem existed.
The problem was the right side of the clutch was rubbing on the load bearing surface of the hub itself. Indeed, at some point, an imprint of the clutch's ridges was cut into the hub's load bearing surface. Thus, the loud ratchet type chattering that would go away if I moved the pedals back just a bit after pedaling.
Removing the imprint of the ridges from the hub's interior load bearing surface would be a challenge. I needed to determine the purpose of the ridges in the clutch. They appeared to be for one or two reasons........ To help the mating surfaces shed grit, grease and other impurities, and perhaps for cooling. The cooling was likely out, as friction would not occur on a positive mating surface.
Because the ridges on the hub's load bearing surface were so difficult to get to, I resolved to split the difference, decreasing the ridges on both the hub and the clutch. I used my Dremel with a slap wheel and slowly worked over the load bearing surface of the hub. Then I turned my attention to the clutch with a file and polishing wheel. I reassembled the hub inside the wheel several times, and spun it on the axle to determine if I had enough metal removed. After the third try, the noise was gone. I disassembled the hub one last time, cleaned and regreased and reassembled it, and installed the rear wheel on the bike. I spun it and braked to with the bike upside down, and everything seemed good. Tired, I went to sleep.
This morning, I woke up ready to test my work. Ilsa looked mournfully though the fence at me as I rolled the long brown Raleigh off the front porch. This was her bike to run alongside, and she knew I was going alone. After working over the brake, I needed to know for certain it was functional. I pedaled about five miles on the PUB, gingerly testing the brake as I proceeded. Finally I worked myself up to a full panic stop with a sideways skid. The brake worked fine. The chattering in my hub was gone.
I pedaled back home, leashed up my riding partner, and we spent the morning riding the neighborhood with no sound but chirping birds, humming tires, padding feet, panting tongues, jingling tags, and the envious barking of less fortunate dogs behind fences along the way.