single wheel assembly for LIKIT Door MFGR LIK-012-1

I have a patio door from LIKIT and is apparently no longer in business. The door is circa 1990. Wheel assemblies are worn to the extent its hard to open and close the door. Upon removal, the axles for the wheels seem be worn. I've added grease, but its still difficult to open and close. I need the correct replacement that will work for this door. Thanks