Double-slider rollers

Looking to replace 1 1/4" metal roller assemblies (single roller at each end) for two (2) sliding glass patio doors (2 x 2 = 4 assemblies).  Age unknown, probably from the 70's, perhaps even the 60's (when house was built.)  
To remove the rollers, you remove a screw from the side frame, tap the frame away from the bottom frame, and then "slide" (or hammer with a screwdriver) the roller assembly out that end of the bottom frame.  Repeat the same for the other end.
There is a center bead (or "rail") at the top of the extruded aluminum inner assembly that goes in a channel in the bottom frame.  Two vertical "legs" next to the bead help carry the vertical load.
The channel mentioned above is also where the screw securing the side frame engages.
For both rollers in the picture, once the wheel bearing froze up, the now spinning axle dug a big groove (or gouge) in the inner assembly, making it very difficult to reuse it for adjusting the wheel height.
I'm looking for replacement assemblies, either identical or at least appropriate.
Thanks!
Derek