Check Your Fuses First
Since both brake lights went out at the same time, it wasn't a bulb, but it could be electrical. I started where I should always start: looking at the electrical diagram to see what the circuit does. If you thought the fuse box for the VW bus was simple with 12 fuses, the MGB fuse box will blow your mind. There are 4 fuses.
I'll pause while that sinks in.
|pic swiped from MGB forum|
Swapping out a fuse box for a modern car is a huge undertaking. Even for a bus it could be a little tricky. Doing a 4-fuse box, however, was ridiculously easy. Circuit by circuit, I simply moved the old connections to the new box. the box sits on the passenger-side wheel arch and is held on with a couple sheet metal screws. A replacement is $8. Seriously. I paid many times that much for a used fusebox for the bus. While this did fix all the other systems, the brake lights still didn't work.
|how to test brakes on a roadster|
As you can see from the picture on the right here, I verified my various solutions by depressing the brake pedal with a roller pole. In the picture, you can see that I got the brake lights to work.
That's it for today. There continues to be a lot going on with the project. Multiple efforts are mid-progress, so there could be a delay in posts while I finish one of them. As always, thanks for following along.