@Jimmrr: Thanks! I always liked ASCII characters art, and I needed a proper signature. Looks a bit funny on mobile, I just realized. It might be fun to start a thread on those...see how creative we can get.
@Mearstrae: You know what? You have a point. I always thought that a brake failure light was a kind of useless feature. If your brakes are out YOU KNOW IT! There's no ambiguity. You notice immediately...as in right when you try to turn off your front street or pull out of a parking lot. Or, on the road, you would probably notice as soon as you try to brake. I can't think of one case where I looked at my dash to tell me something about the driving characteristics you usually just feel. ("Interesting! This light is telling me my steering wheel is missing!")
I guess I'm just trying to be thorough. Somehow, I assumed the shuttle valve was like a pressure maintainer thing. Like if one side went out, it blocked the pipe. But I guess you're right - the plumbing is two separate systems(nice). I was going to wire up the light later. The parts manual has a wire loom listed, and it has a similar light for vacuum booster pressure, etc. All look like simple 2-wire jobs...so I was going to just wire it myself. But I wanted to put it in there and get the plumbing done, then come back to the wiring.
I'm sort of doing this as a rolling restoration out front of my house. So, I have to kind of do it one weekend at a time. I try to plan whatever I cam do in 1-2 days before I have to button it up and let it lie for another week. Last thing I want is to get 50% in and find I need to order a part and wait 2 weeks with all my pipes and greasy bits open to the elements. So, I'm kind of exhausting myself trying to get everything right before I start. I guess that's a fool's errand with Land Rovers, because I'm finding no matter how much planning and research, it always throws me for a loop ("I swear this is the right part number! What the...?!")