1 1/2" nylon rollers

Rollers are 1 1/2" diameter with an eccentric roller axle that allows for door adjustment. There are 2 rollers on bottom and top. The bottom of the door is 5/8" wide and 1 7/16" deep. Please advise on repair and parts needed. I do not see any replacement on web site but open to suggestions. These are very old heavy big doors.