>  You can make the older
> ones slide easy for a few days with some lube--white
> grease sprayed or Triflo, but then it gets hard again.
well i realy gotta say that you have to try
Fluid Film http://www.eurekafluidfilm.com/
I did that 4 weeks ago on my 85 sliding door & it still
sides like it on a cushion of air
of course i wanta see it 12 mths from now
but I was told about this product from the garage
door installer that swear it cuts down on their service calls
and they figure it works for about year w/o a quick respray