Brake problems

Today I got pretty lucky with my brakes. I was hauling a load with the truck weighing around 85,000 pounds when I started to slow down to get ready for a right turn I had to make. I'm not sure if it was right before or right after I applied the brakes. I felt as if I run over something with my steer tires and a heart beat later I felt my drive tires run over something and one of the drive tires blew out. I hadn't seen anything and was thinking a part had broke loose from the truck, so I started slowing down. It took just a second or two to figure out I didn't have my full braking ability. I used both my brakes that remained and the gears of the truck to slow myself down enough to make my right turn safely and get to where I could check things out. At first glance it just seemed that the drive tire was blown and an airline was leaking somewhere in the engine area. Since I was at where I was going to unload I went ahead and got the truck unloaded. It doesn't take long to get unloaded, maybe it takes 10 minutes total to unload. I have to unstrap the load and I saw my steer tire seemed to be low on air but was able to unload and as I was getting back into the truck I knew I wasn't going to far since it was almost completely flat by this time. I got myself out of the way of truck traffic and this is what I found. The brake drum had busted in half on me and it had cut the value stem completely off allowing the air to leak out at a good pace. If I had been driving on a busy road or the steer tire had lost air faster it could have been bad.