What was found
DURING TAKEOFF ROLL, F/O CALLED 80 KNOTS, CAPTAIN SAW 50 KNOTS, 30 KNOT AIRSPEED DIFFERENCE. AT 100 KNOTS ON F/O AIRSPEED, CAPTAIN SAW 70 KNOTS. REJECTED THE TAKOFF AND COMPLIED WITH QRH. INSPECTED BRAKES AND TIRES DUE TO REJECTED TAKEOFF IAW AMM 05-51-16-00. NO DAMAGE NOTED. PURGED CAPTAINS PITOT LINES AND PROBE IAW AMM 34-10-00-03, FOUND NO BLOCKAGE. PERFORMED LEAK CHECK OF BOTH CAPTAINS AND F/OS PITOT SYSTEMS AND FOUND CAPTAINS SIDE LEAKING. ISOLATED LEAK TO PITOT DRAIN IN NOSE WHEEL WELL NOT FULLY SEATED. PERFORMED PITOT DRAIN SERVICING IAW AMM 12-24-34. PERFORMED SECOND LEAK CHECK AND PERFORMED OPS CHECKS IAW AMM 34-10-00-05-0 OPS CHECKS GOOD. LEAK CHECKS GOOD.