I have a TAZ 5 that is over 2 years old. I notice a slight wobble on the build plate bushings, but it does not seem to affect the build yet. When I wiped the rods, I notice that there is a little grey dirt. Does this mean that the bushings are worn out?
If it is not affecting the build, no need to change anything out yet. For a “working life” reference, we change out the bushings in our cluster about every 9months for a machine running 24 hours a day seven days a week. That would be about every 2 years for someone running their printer 8 hours a day every day.
The bushings used on the printer are self lubricating. This dirt you are seeing is likely dust from the air accumulating on the rods and mixing with the lubrication. Wiping these smooth rods off every month or two will help prolong the wear and tear on the bushings, as it will keep it nice and smooth. (That dirt build up is completely normal.)