On the topic of trailer replacement parts, it's true, Amera Trail may not be carrying parts since they have changed to other suppliers.
I do think you can get parts from any good trailer supply store. I just picked up replacement bearings, races and seals from Henderson Parts here in Orem, UT 888 586-8744. They had several options for all these parts (some made in Romania, China or Taiwan) at different prices. A full set for my dual axle trailer cost $80.00. Most of the parts they pulled off the shelf in front of me and didn't need to go into the back-office inventory area.
Part Numbers:
Qty (4) - L68110 Inner Bearing Cup/Race
Qty (4) - L68149 Inner Bearing
Qty (4) - L44610 Outer Bearing Cup/Race
Qty (4) - L44649 Outer Bearing
Qty (2) - 58846C Spindo Spring Seal
Qty (2) - 233-168-SP2-1 Spindo Spring Seal