Bob said: "...on several occasions I've been flagged-down by frantic drivers claiming my brake lights weren't working (they work)."
The failure mode of the hydraulically activated brake switch is gradual--that is, as time goes on it takes more and more pressure for the switch to close and provide a circuit to the brake elements. So, when you stand on the brakes to see if they are working they will give you a positive whereas under normal braking with less than panic-stop pedal pressure they may not.
In Vintage racing all cars--except for Formula cars--must have working brake lights. Whenever a car goes through pre-race tech inspection we are asked to demonstrate to the inspector that the brake lights work and it is safe to state that no car gets to the grid without them, yet it is very common to see cars whose brake lights are not working on the track, this because while at tech the driver stood on the pedal he naturally modulates his braking on the track. On numerous occasions I have told other racers that their brake lights were not working and almost always they will test them by stomping hard on the pedal and telling me I am wrong.
Installing a hydraulic switch is sometimes a real PITA since the hard lines are tied down in place and difficult if not impossible to cut, reflare, etc. without having to plumb new lines. I have gone over to switches built into a banjo fitting that bolt onto the existing brake cylinder and only require a longer bolt and perhaps new crush washers, etc. and they would take but five minutes to replace. Get them at Pegasus:
https://www.google.com/search?clien...0i46k1j0i22i30k1j33i160k1j33i21k1.FRDaAdLaiqE