L BRAKE FAILED.

Narrative

EXECUTED A NORMAL LNDG AT Q68. PLACED PWR LEVERS INTO REVERSE; OBSERVED BOTH BETA LIGHTS ON; WENT INTO FULL REVERSE. ROLLOUT NORMAL; SLOWING NORMALLY. MOVED CONDITION LEVERS BACK TO START/TAXI. ACFT SWERVED R AND FULL L RUDDER AND BRAKE WOULD NOT CORRECT. BRAKE PEDAL WENT ALL THE WAY TO THE BOTTOM WITH NO EFFECT. ACFT L RWY SEVERAL SECONDS LATER TO THE R. ACFT SLOWED BUT DID NOT CONTACT ANY FOREIGN OBJECTS. SINCE L WAS NOT WORKING; TURNED R; DID A 180 AND PROCEEDED BACK ONTO RWY . PUMPING L BRAKE CORRECTED PROB. LUCKILY; I HAD AN A&P RIDING ALONG. WE DID A VERY THOROUGH POSTFLT INSPECTION OF PROPS/WHEELS/BRAKES/LINES IN WHEEL WELL AND FOUND NO DAMAGE. RETURN FLT NORMAL. INSPECTED ACFT ON RETURNING TO HOME BASE AND FOUND NO DAMAGE/LEAKS/DEBRIS. JUST MUDDY WATER ON GEAR DOORS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THIS ACFT WAS A CONQUEST 2 WITH A 331-8 ENG. THE 4 BLADED PROP WAS JUST INSTALLED LAST NOV. THE OCCURRENCE WAS IN JAN. THE RPTR ALSO PLTS THE CHEYENNE 3 AND THE KING AIR. THE BEFORE LNDG CHKLIST ON BOTH THOSE ACFT CALL FOR TESTING THE BRAKES PRIOR TO LNDG BUT THE BRAKE TEST IS NOT CALLED FOR ON THE CONQUEST. WHAT CAUSED THE ASYMMETRY AS HE SLOWED THROUGH 60 KTS IS A MYSTERY. ALSO; WHY THE L BRAKE WAS WITHOUT PRESSURE IS ALSO A MYSTERY. THERE WAS NO XWIND. THE NOSEWHEEL STEERING HE DIDN'T FEEL WAS AT FAULT AS IT IS A DIRECT DRIVE AND HAD BEEN TRACKING STRAIGHT UP UNTIL THE POINT THE CONDITION LEVERS WERE BROUGHT TO START/TAXI. HE SAID THE NOSEWHEEL STEERING IS NOT EFFECTED BY CONDITION LEVER POS AS IS THE CASE ON SOME ACFT. HE DID NOT NOW WHETHER AIR WAS IN THE BRAKE LINE. BEING ABLE TO PUMP THE PRESSURE UP WOULD BE INDICATIVE OF IMPROPER SVCING OF THE BRAKE SYS WITH HYD FLUID. THE RPTR WAS SATISFIED THAT THE REVERSE WAS NOT CAUSING THE ASYMMETRY. THE RWY WAS WET SO HE COULD NOT DETERMINE IF THE R BRAKE WAS DRAGGING. THERE WERE NO SKID MARKS.