I recall last year there was a horrific story by a fellow Bolter describing how he was nearly killed in a big truck as a result of failed brakes. (Can someone find this and post a link?) His story should be a stern warning to all of us to know how to minimize personal injury if your brakes fail.
Back in the day, how to handle brake failure was part of driver training. The object of the game is to maintain control and walk away with minimal injury.
Things to do depending on the situation:
~ Don't panic.
~ Jam on the emergency brake. Even if you lock up your rear wheels you will still maintaing some steering control.
~ Downshift and turn engine off unless you have one of those steering columns that lock with the key off.
~ Swerve left and right to slow your forward momentum but not so violently as to cause the vehicle to overturn.
~ Sideswipe objects along the side of the road. Prioritize life before property!
The very first thing I did to my truck was to install power disk brakes and a dual master cylinder.