A 450 that was a truck tractor or a grain truck could very well have air brakes. If it was a fire truck, it would have hydraulic brakes. Lift the hood and see if there is a compressor. If you have air brakes, the rear axle will look something like this.

https://photos.google.com/share/AF1...TEZWbjBHVG1DaEVFeUtSa0YtQ25wWGlkbTJpZWRR