I have a 2005 19' Keystone tandem axle travel trailer and (yes I know) never serviced the axles. I pumped some grease into the zerks every few years, but haven't repacked the bearings or adjusted the ...
Take a good look at this thread by one of our more informed and helpful members John Barca. It shows, in detail and with many pictures, just how to adjust brakes and lube your axle bearings. Barney