Check under the hood. The master cylinder is connected to the brake pedal.
Wanted to add a few pictures showing location, but I keep getting an error message jpeg and gif files are not supported. Sorry
I found this copy of the Operator's Manual https://manuals.deere.com/cceomview/O...Index.html?tM=
Scroll about 2/3 of the way down on the left to the "Servicing Steering and Brakes" section.