|Roller removal risky, rejected.|
I lifted the door off the track and quickly saw that replacing the rollers would be risky: it looked like I would have to disassemble the frame and possibly ruin the rubber lining, not to mention damage the mirror.
Using a small screwdriver, I adjusted the old rollers higher. The doors slid more easily, but they were still difficult for him to push.
The situation called for the magic spray. Back to the hardware store to return the rollers and pick up a $4 can of WD-40.
The company has added a lever to the spray can top. No longer does one have to mess with the red straw, which is now affixed to the can. A clever modification, it became a tactile pleasure---perhaps that's a guy thing---to spray the rollers and the metal track. The doors slid easily. I placed the WD-40 on his shelf.
The magic spray, invented 59 years ago, is as miraculous as any smartphone or designer medicine. It will probably outlive them all.