Citation Excel (C560XL)
Flight Crew Air Transport Pilot (ATP)
Troubleshooting; Situational Awareness
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Maintenance
General Maintenance Action
Aircraft; Equipment / Tooling
Repeat discrepancy for 'spongy brakes; left seat; left pedal.' Multiple corrective actions 'bled brakes; ops satisfactory.' With the corrective action available to us; we thoroughly checked the brakes by pumping the brake while observing the pins on the brake pads. Cable snapped while checking. Corrosion of the cables should be inspected anytime a brake issue similar to this is reported as a discrepancy and/or an AD should be issued to check all cables more frequently.
The reporter confirmed that the brake cable broke because it was corroded. The cable runs from the brake pedal to the hydraulic unit which supplies the pressure to the brakes. The reporter told me that many of the Cessna 560 Citation V Model XLS have cables that have been found corroded; but this is the first one that he knew of that broke. The reporter confirmed replacing the cable fixed the spongy brake pedal.
C560XLS First Officer reported that the left brake pedal felt spongy. The cable snapped while pumping the brakes and checking the pins on the brake pads.