PA-31 captain reported brake malfunction while taxiing.

Attributes
ACN	1637495
Time
Date	201904
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Dawn
Aircraft 1
Make Model Name	PA-31 Navajo/Chieftan/Mojave/T1040
Operating Under FAR Part	Part 91
Flight Phase	Taxi
Route In Use	None
Flight Plan	VFR
Component
Aircraft Component	Normal Brake System
Person 1
Function	Pilot Flying Captain
Qualification	Flight Crew Multiengine Flight Crew Instrument
Experience	Flight Crew Last 90 Days 150 Flight Crew Total 465 Flight Crew Type 15
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Published Material / Policy Deviation - Procedural Clearance Ground Event / Encounter Loss Of Aircraft Control Ground Excursion Taxiway

Narrative:

While taxing the airplane; the left rudder and brake locked up and would not turn the airplane. At this time we brought the power on both engines to idle but the aircraft was still continuing to move. When we used the brakes on the aircraft the only brake that worked was the right and it pulled the aircraft into the grass off of the taxiway since the right brake was the only one that had engaged. No damage was done to the aircraft or taxiway and we proceeded to advise the tower that our brake seized up and that we will need our company to tow the plane from where it was. They advised an aircraft to go around us and had room to do so; then we towed the plane back to our hangar for inspection and maintenance. I was advised that it was a fouling of a piston that was not allowing pressure to build up in the left brake which caused the brake to not work after the incident.

Original NASA ASRS Text

Title: PA-31 Captain reported brake malfunction while taxiing.

Narrative: While taxing the airplane; the left rudder and brake locked up and would not turn the airplane. At this time we brought the power on both engines to idle but the aircraft was still continuing to move. When we used the brakes on the aircraft the only brake that worked was the right and it pulled the aircraft into the grass off of the taxiway since the right brake was the only one that had engaged. No damage was done to the aircraft or taxiway and we proceeded to advise the Tower that our brake seized up and that we will need our company to tow the plane from where it was. They advised an aircraft to go around us and had room to do so; then we towed the plane back to our hangar for inspection and maintenance. I was advised that it was a fouling of a piston that was not allowing pressure to build up in the left brake which caused the brake to not work after the incident.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.