What was found
IN FLIGHT, HYDRAULIC QTY DROPPED TO 4. CREW RAN QRH PROCEDURE AND SHUT OWN RT HYDRAULIC SYSTEM. DURING DESCENT, IAW THE QRH, ATTEMPTED TO RE-PRESSURIZED THE RT SYSTEM. THE RT SYS INDICATED 3000 PSI BUT QTY DROPPED TO 0. MAINTENANCE FOUND THE LT WING OTBD ANTISKID VALVE HOUSING CRACKED. R & R VALVE. LEAK AND OPERATION CHECKS GOOD IAW MM. CLEANED AFT BELLY AND MAIN GEAR WELL, APU INLET WAS DRY AND NEITHER PACK HAD SMELL.