What was found
LANDING GEAR WOULD NOT RETRACK UPON RETRACTION, LT GEAR C/B POPPED, RESET ONCE TRIED ONE TIME, GEAR WOULD NOT RETRACT. USED GEAR BLOW DOWN BOTTLE TO ENSURE DOWN AND LOCKED. REMOVED AND REPLACED LANDING GEAR CONTROL MANIFOLD IAW 750 M/M 32-30-02, OPS AND LEAK CHECK GOOD.