It’s impossible to fix something without understanding how it’s supposed to work. Brake system repair decisions can be difficult to make, and costly to execute, without a basic understanding of system ...

It takes a robust braking system to bring 80,000 lb. (36,000 kg) of moving tractor-trailer to a halt. And half of that system sits on a trailer, about 45 feet (about 13.5 meters) behind the driver.

Most incidents involving total air-brake failures go unreported officially and simply become the stuff of legend. But a few too many of them have resulted in very public collisions. Until recently, ...