Disc brake light switch

I recently rebuilt the front end on my '74 Roadster including new fork tubes and Bushings, Landsdowne dampers, headlight ears, brake pads, fluid hose, fluid, Blanchard ground and drilled brake disc, and repainted, master cylinder. All back together and no disappointments at all!! Braking is improved and it looks
stunning. After bleeding the air and topping up the brake fluid the brake is solid with no mushiness or wooden feel at all. The brake light switch worked fine.
After a ride, I discovered that the brake light switch is no longer working. Yes, the electrics do work. That leaves either a bad switch or ????.
Any thoughts of how to test the brake switch or what else in the master cylinder might be causing this?

You don't say if you're using the stock master cylinder or one of the replacement ones like the Brembo's that Mat. from Colorado Norton Works sells. I know that Matt has had problems with the microswitches that used to come with the Brembo's and has now switched to a different type of switch. if that's the kind of master cylinder you're using you should call Matt and order one of the new in-line type of switches. I know of at least one person who has had to change them out with good success. Glenn T.S.

And if its the old Lucas job you need Lucas SPB 401, well you don't as they are rubbish, you need Intermotor part number 51610 which Morgan owners report as being more reliable than the Lucas version.

The Lucas unit fills up with gunk over the years. I actually got one working again after flushing it out with solvent and pushing on the contact inside , although it was a tedious effort.

Try to do a continuity test with a voltmeter on the two terminals on the pressure switch. Pull the boot off to get at the switch and take the two female spade connectors off. attach your voltmeter leads to the male spades and squeeze handle. If you get continuity then the trouble is in the wire loom. If you don't get it, then it is in the switch.
Cheers,
Thomas

If you need a switch, I have one in the bonepile.

I had Ella at http://www.OldBritts.com ship one to the hotel I was headed to. 10 minute job in the parking lot. :mrgreen:
You've already troubleshot the problem, right, "the electrics work", (light comes on when wire terminals touched together) what's the mystery? :?: