'40 brake lamp switch / master cylinder issue?

[Mart]

Mike, all, would it be an idea to rig up some sort of device to test the switches? An old but serviceable master cylinder, a lever and a couple of fittings might allow at least a heads up of a bad switch. Someone suggested using air.. is that feasible? What psi is needed to make the contact in a good switch?
I must admit, I fitted a mech switch in my sedan after a couple of failed hyd switches. My pickup still has it's original hyd switch and still works.