My first new seal on my 51 1 Ton lasted about 7 years. Then it began to leak, only when I was driving the truck. It didn't leak just sitting. I thought maybe the bearing was starting to get sloppy but that wasn't the case. When I replaced the seal, I found that the previous one had shrunk in the center making it extremely tight on the shaft. So when the yoke was turning, I would guess that the rubber was distorting. A new seal fixed the problem.
I am still curious where the felt ring was mounted because they are not required with the modern seal.
