Thanks to Joel, Pius, Terry, Trevor, Dan, Alistair and Frank (hope I didn't miss
anyone) for suggestions and pointers to url's to replace the rollers on the ends of
the lifter arms.

    http://www.members.shaw.ca/albell/mods2.html
    http://members.aol.com/Fkc43/roller.htm

Instead of the bi-fold door top pivot guide, I used flanged nylon bushings. While in
Ace Hardware looking at the former, all of the bins of hardware were behind me, so I
started looking and found the latter. They come in various sizes, so I got two with
the flange slightly larger than the enlarged hole at the end of the track and two
smaller, shorter ones. The smaller ones fit tightly inside the larger ones and sort of
give additional support to the larger flange. The inside diameter of the smaller one
is also a better fit for the screw that holds it to the lift arm. I used a Dremel tool
with small grinder wheel to shorten everything to the proper length. The Dremel melts
the nylon rather than grinding it away, but same result.
Found proper size screws in my parts bins and two nuts and star washer each to lock
together. I will probably replace these with nylok nuts. Drilled out the original
rivets in the ends of the arms, and attached the nylon bushings and it works great.
Just need to remember before pulling into the garage, "down periscope, down skylight".
Jerry in too-hot Arizona (not even Phoenix)