[TR] Re-use of old brake linings

[Nolan]

Don't claim to have an answer to your question about the shelf life of the 
adhesives, but this PDF has lots of information on the chemical bonding of 
lining to shoes and pads. 
http://www.conklinequipment.com/pdf/LT-4421Friction_Manual.pdf

I've had a few shoes fail on me over the years.  Reading through the PDF I 
see that I might have been the cause.  I tend to use cleaning agents 
liberally on braking parts, and some of them are solvents for the bonding 
adhesive.