After Market 19mm Master Cylinder Question Options

[Literati914]

So, I wanted to verify that members here had ACTUALLY installed a two post brake warning switch sender on the 19mm (after-market) Master Cylinder with success? Mine came from 914rubber and when installing it, I removed the single pole unit and installed a two pole sender, basically because I had a free ground there already and so it just seemed the better option.

I'm having difficulty getting the light to stop blinking and was thinking I might try to put the single blade sender back in.

To isolate the issue, I pulled just the M/C wire from the back of the gauge, with the e-brake and 'fasten belt' wires still installed at the warning bulb (it's a '72) - those both worked as intended, with the release of the e-brake turning off the flashing warning light. Then I removed those two wires and installed just the M/C wire - I just get flashing even after pulling the spade connectors to reset the sender.

So, then to check for a possible short in the M/C wire, I removed it from the bulb and the M/C and ran a separate external wire from the bulb socket to the M/C... still it just blinks. So it's not the wiring. I put it back together temporarily without hooking the M/C warning wire back up.

Maybe it doesn't like the two-pole? I'd like to know exactly what's different internally that the new units don't need an external ground wire, if anyone knows.. and if anyone can confirm that theirs works with an old style sender, that would be great.

[Dave_Darling]

What happens if you unhook both wires from the switch? If the light keeps blinking, the switch isn't the problem.

Have you pressed the reset button on the switch? Most of them will "latch" closed when they detect a pressure imbalance, and you have to press the button to open up the switch again.

--DD