How do you install a foot valve in a 1984 Peterbilt 359?

To install a foot valve in a 1984 Peterbilt 359, first, ensure the truck is parked on a level surface and the air system is depressurized. Disconnect the old foot valve by removing the air lines and any mounting hardware. Install the new foot valve in the same position, securing it with the mounting hardware, and reconnect the air lines, ensuring all connections are tight and leak-free. Finally, test the brake system to ensure proper operation before returning the vehicle to service.