??? I have two tractors. Neither has an "emergency brake". If you get off the tractor you put the transmission in the Park position - no provision for any brake to be on when parked.
My old B414 International has a parking brake, similar to what was found in old trucks.
Interesting history on these terms. Before dual-reservoir brake master cylinders, it was required that all road vehicles have an “emergency brake”. There are requirements built into that term, that the brake must be able to stop the vehicle from a certain speed in a certain amount of time, I don’t recall the numbers now.
The idea was that, on these single-reservoir systems, any single brake line or piston seal failure could cause the entire system to depressurize, and you’d lose your brakes. I’d guess older members here can tell us how common this was.
Then when the safer dual-reservoir brake master cylinders became a thing, the requirements for the auxiliary brake were reduced from emergency stopping to just parking, and the name of these systems is “parking brake”.
Every tractor I’ve ever owned has had a parking or emergency brake, and to my recollection, they’ve all worked the same:
1. Press brake pedal as hard as you want.
2. Pull a lever or engage a stop that locks the brake on at that pressure.
On some of the oldest tractors I’ve owned, (Cub 123 and maybe the Bolens 1030), the parking brake was a stop lever on the pedal itself, so you’d adjust its tension by adjusting the pedal linkage. But all would work to keep the tractor from creeping, even if the HST center zero fell an little out of whack.