So the manual calls for a 6204UU and a 20x47x20.6(NTN). The 6204 is a common size, 20x47x14 so there is a big difference in bearings, the righthand one is 6.6 mm wider and a heavier duty bearing. I can't remember what the UU stands for, I think maybe equivalent of 2RS, Brock?? 2RS being 2 rubber seals. The 20x47x20.6 is a 5204 with the NTN just standing for the maker. It is probably a 52042RS. Your local bearing supplier should have them on the shelf.