You need to pull them to clean, inspect and repack every couple of years.
I grease my Trailer bearings regularly, but after bearing/brake trouble earlier this year with the stacker, I put inspecting and repacking all trailers on my off-season To Do List. Two bearings on my enclosed trailer needed replacing, as did two on my open trailer.
As you can see from one of the open trailer’s bearings – I fixing to be spending time on the side of the road real soon. I’m sure a good part of it is that the Texas speed limit is 75, and I use that as a suggestion only.
Now is a great time to spend a couple hours cleaning, replacing and repacking your trailer bearings. It sucks doing on the side of the highway. If more than one bearing needs to be replaced, I’ll generally replace them all. I’ll clean, repack and baggie the good used set and keep them and seals in the trailer in case of a roadside failure.