In the brass junction block where the lines from the Master Cyl feed in,and the various brake lines
attach,there is a brake switch which flashes a warning light on the Dash in a '67 Plymouth..
Anyone know where to get a new one?? Even tho
My brake system has been bled,brake shoes adjusted,and the master cylinder is full,the Brake warning Light still flashes as soon as I hook up the wire to that switch,so I'm assuming
that the switch is bad??

That junction block *is* the switch, mine's been acting weird too. Unfortunately, no idea where to get one.

NAPA Knowhow!

If the light comes on as soon as the wire is connected, the spool inside the splitter isn't centered; in some cases it's necessary to remove the switch and manually center the spool.

If the spool keeps moving off center there is probably an imbalance in the system even if there is no air or external leaks. A master cylinder can fail internally and show no external signs of distress.

Well, if anyone finds 'em, post a link... always good to have a spare!

Thanks for info regards spool,I'll remove that
switch and check-don't think I have mstr cyl problem,I just rebuilt that B4 installing...Still would like to purchase new switch,am gonna take pix and then try NAPA as suggested.

The "switch" as they call it is only a contact that touches the spool (differential piston) to make a ground for the warning light, I'd be surprised to see one that needs replacement unless it's leaking.