What was found
ON FLIGHT 3932 (SYR TO DTW) DURING FLIGHT NOTICED HYDRAULIC SYSTEM NR 3 QUANTITY FALLING AT A RATE OF 5% IN MINS. WHEN WE DROPPED THE GEAR ON FINAL PRESSURE WENT FROM 25% TO 0% ALONG WITH GEAR DISAGREE WARNING MESSAGE. WENT AROUND AND PERFORMED QRH. LANDED ON 22L AND WAS ABLE TO EXIT VIA HIGH SPEED. REMOVED AND REPLACED NR 3 HYDRAULIC SYSTEM PUMPS A+B. REPLACED LINE FROM BALL ATTENUATOR TO PULSE DAMPNER ON BOTH PUMPS IAW CRJ 200 AMM 29-12-03. LEAK AND OPERATIONS CHECKS GOOD. PERFORMED FUNCTIONAL CHECK OF MAIN LANDING GEAR RETRACTION /EXTENSION SYSTEM IAW CRJ 200 32-30-00. ALL CHECKS GOOD. OK FOR SERVICE.