O.K. to clear it up- it wasn't a compression fitting. I don't know what they are called- but it is the same type fitting that all my brake lines use. What is that- flare? Anyhow, all the adapters and such that I used are standard brake parts that I got at NAPA. The valve part is the only real part that I question in this as the PSI rating may or may not be right.
I don't know about the part where you have to have a seperate circuit for the brake. I had none and not really an option to put one on unless I changed my axles, or did a transfer case brake like some others. I thought that a booty-fabbed brake was better than none.

I did, however use this same valve for a few months on the truck and it never blew out or leaked. I will use it around the farm for a while and keep and eye on it.

I guess this is what I needed to add to the original post-
This type brake may be illegal in your area and even if it's not- it's not the safest idea and as such should be used only on mud trucks where you might have brake failure.
Sorry. I'll edit now.
-B.