Steering Box late 50's

[tessiers]

Re-building a steering box from the late 50's in an old Michigan tractor shovel model 75a. when I opened the box up there were 2 nylon thrust bushings top and bottom of the worm gear. I am quite skeptical they are original equipment, anyone know when they may have started using nylon? I'm having a hard time finding exactly what I want, I have a great bearing supplier locally, thought if I got the old out they could match them up, now I don't know what to try next. Incidentally I turned out a bushing from an old plastic snow plow cutting edge, on my lathe, and put it back together to get me by.

 

[stuckmotor]

When I was a kid in the late 50's my swing set had what I believe were nylon bushings at the ends of the chains.