Cessna 402/402C/B379 Businessliner/Utiliner
Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Aircraft Equipment Problem Critical
Air Traffic Control Issued New Clearance; Flight Crew Returned To Gate; General Maintenance Action
Aircraft
During the preflight; I paid close attention to some previous write-ups because the brakes have been previously written up just a few days prior. After leaving the gate; I pressed my brakes as instructed by the normal procedures handbook. I did not feel any resistance at all on the brakes; but decided to pump them several times to see if that would improve the situation. I made this decision because sometimes the brake fluid is thick when the aircraft is cold. I wanted to determine if the copilot brakes were connected to give a proper description to Maintenance. Unfortunately these actions did not help. When we began our runup; I instructed the FO (First Officer) to hold the brakes with me to see if we had any braking control at all. The airplane began to roll at 1700 RPMs despite both of us holding the brakes. At that moment; I informed ATC that we would be returning to the gate and that we would have to cross the runways; but had little to no braking action. We received clearance to cross both runways and made a successful gate return.
C402 Captain reported returning to the gate for maintenance when the brake system malfunctioned during taxi and run-up.