This component is a combined brake and clutch master cylinder for a self-propelled forage harvester. It converts mechanical pedal input into hydraulic pressure to actuate the service brakes and the clutch pack. The cylinder sits in the cab floor assembly, with its pushrod linked to the pedal linkage and its outlet port connected to the hydraulic distribution block. A worn or leaking master cylinder causes a soft pedal, reduced clutch disengagement force, and eventual loss of drive or braking function. The manufacturer machines the bore and piston to match the original assembly's clearance, which maintains the correct pedal feel and actuation stroke without requiring shimming. Use only DOT-3 or DOT-4 brake fluid. On reinstallation, bleed the system completely to remove trapped air.