What was found
AFTER SELECTING GEAR DOWN, POWER BRAKE LOW PRESS, ANTI SKID INOP ANNUNICATORS CAME ON, NO BRAKE PRESS EITHER SIDE. GO AROUND, ON SECOND APPROACH BOTH LIGHTS REMAINED ON FOR 5 SECONDS THEN EXTINGUISHED. BOTH PILOTS HAD POSITIVE BRAKE PRESSURE, NORMAL LANDING WAS ACCOMPLISHED. BACK UP AIR BRAKING NOT USED, ALSO NOTICED BRAKE HYD PUMP VERY NOISY. - JACKED A/C TO TROUBLESHOOT AND FOUND NORMAL TRANSITION OF BRAKE OPER GEAR UP/ DOWN NO DUP OF PILOT SQUAWK. BRAKE PRESSURE PUMP OPER SOUND NORMAL. INSPECTED SYS COMPONENTS FOUND SKID CONTROL RELAY KN002 SOAKED WITH SKYDROL REPLACED RELAY OPERATIONAL CHECK OF GEAR TRANSITION/ BRAKE SYS ENERGIZING SYS DETERMINED SATISFACTORY WORK PERFORMED WITH REFERENCE TO MFG 560 MM.