When to Replace, Do-it-Yourself
I have an airvac zx6000 gold, the amber light came on (after 9 years) indicating half-life of the brushes. a) can I wait a few more years to replace them? and b) I see Motor Brush (motors 11-6765, 7939) on your site, looks like these should be for my motor - are they consumer-replaceable? (I usually make my own repairs to things.)
Motors go bad when the brush/communtator connection goes bad, or when the bearings go bad. You can wait until the motor burns out or you can check the brushes soon. The lead is 3/4" long when new. If any of them are down to 3/8" you should replace those ones because if they wear down they damage the communtator they touch. And yes, you can replace them yourself. There are how-to instructions available to click from on the motor brush part online.