A self-lubricating bearing assembly for supporting a load on a guide rail which includes a carriage having first and second ends, a guide surface adapter for translation atop the guide rail and an end cap assembly which mounts adjacent one of the ends of the carriage. The end cap assembly includes a seal and a lubricating assembly having a lubricating block made from a lubricant composition and a compression housing for enclosing a periphery of the lubricating block and for biasing the lubricating block against the guide rail to cause the lubricant to contact the rail.