take it down a dirt road after you get everything installed and get it rolling pretty good and apply the brakes. Be really careful the first few times because the back may want to swap ends with the front.

If the back brakes lock up first you need to adjust your valve. If they don't lock up at all you need to adjust your valve. thus the desire for an adjustable valve. do you need it? not really if your willing to crawl under your truck to adjust the one you have until it's right. the reason people tie them up is because the proportioning part isn't designed for big brakes. so when you load the bed with stuff it squats the valve and applies too much rear brake because it is proportioned wrong for the size brakes you have. the only reason the installed it in the first place was so that you could have better brakes under a loaded situation. but if you set it up right on the dirt road and just tie it in place. you'll be happy with loaded or unloaded. but if your looking to haul stuff all the time then get the adjustable in cab valve and be done with and have the best of both worlds.

that gm swap kit is sweet. I just wish I had known about it before I got the fj80 master cylinder. but that's life.

anyway you will have to run the dirt road about ten or so trips to get it adjusted right. once it is right all four tires should lock up at the same time. then go out on the pavement and stomp it to the floor and see if the back tires lock up. if they do let it down just a little bit more.the last thing you want is your rear passing your front in an emergency stop situation. especially with a lifted truck with bigger tires.

I hope this help this is how I was instructed to do it and it worked great. once they were adjusted I just locked the valve in place and haven't touched it since. I do recommend the 10lb antibleed back valve or check valve. my pedal is soft the first time you push on it after driving it a while.
the check valve will stop that problem I just been to cheap to get one yet. oh yeah and lazy to boot <img src="/forums/images/graemlins/smile.gif" alt="" />

the fj80 pedal works as a direct bolt on except for a little tubing bending but it still has a good bit of pedal drop before the brakes hook up. but it isn't too bad.It wans't half way that's for sure but it wasn't at the top like my original set up either. but my fj80 master with the tank was like 150 bucks once I was done so the gm kit with master cylinder is a great deal at $95. imo