Yes, if you can get a hold of some bearings and you have the time, patience and fortitude, you can pull an MD180 spine apart, replace bearings and put it back together. But its an extremely fiddely process that will probably take at least a couple of hours to do. That said, last time I checked Hobie did not have replacement bearings for MD180 spines available, and nor have they done anything to encourage dealerships to try and repair these spines or even replace bearings. I'm assuming that's because it's way too labour intensive for Hobie to be expecting dealers to be doing it.
FYI, if you've encountered problems with bearings on an MD180 drive, chain tension may be the culprit. Either too loose or too tight, most likely the latter (especially if it's the rear sprocket that is a problem).
Personally I prefer the simplicity and durability of the Glide Tech drive. It performs just as well (if not better), easier to pull apart and service / replace parts and less expensive to. Sure, the MD180 can pedal backwards, but the pros end there. We wrote about the differences in the current Kick-Up drive options here:
https://slhobie.com.au/miragedrive-gt-ku-vs-md180-ku/