A main piston bushing for a service valve portion of a brake control valve includes a cylindrical sidewall defining a central passageway extending longitudinally through the main piston bushing, the central passageway being surrounded by an internal surface of the cylindrical sidewall. The central passageway is configured to receive the main piston assembly of the service valve portion. The internal surface of the cylindrical sidewall includes a first ramp and a second ramp defined therein, the first ramp and the second ramp being configured to engage a portion of the main piston assembly of the service valve portion to restrain movement of the main piston assembly.