I've had a leaky banjo bolt, the one that attaches the master cylinder, brake lines, and brake light switch, for years.? After several tries, it's fixed.? The picture has the clue:

The Jeepsterman sold copper seals/washers of the correct inside and outside diameter.?? But, at least with the combination of parts I have, the washers need to have different thicknesses to have both seal properly.

I'd seriously injured the washer in the forward position trying to fix the leak in the back position, went to an auto parts place, they had washers of different thicknesses.? Eventually this combination did the trick. Tightened to 30 lbs.

The stoplight switch shown is supposed to be compatible with DOT 5 fluid,? hope it lasts.