What was found
(CAN) 1) AN OVERHAULED PARKING BRAKE VALVE WAS INSTALLED TO REPLACE A UNIT "ROBBED" TO SERVICE ANOTHER AIRCRAFT. NOTE: AIRCRAFT HANGARED MORE THAN TWO (2) DAYS, THUS WARM FLUID AND SYSTEM. 2) OVERHAULED VALVE INSTALLED. 3) UPON FIRST PRESSURE TEST FOLLOWING INSTALLATION A "HEAVY LEAK" SPRUNG AT THE PISTON SHANK. NOTE: ONE MAY THINK "O" RING OR SEAL IS MISSING INSIDE. 4) UNIT REMOVED. RED TAGGED. PART IDENTIFIED FOR KEEPING AVAILABLE FOR 21 DAYS AS PER 24-0038 INSTRUCTIONS.