A B757 Captain reported that after he discovered hydraulic fluid on a landing gear door and requested maintenance inspection; the aircraft was released for flight before a mechanic had actually been present to inspect the fluid's source.

Narrative

During the preflight exterior inspection I saw hydraulic fluid on the left main landing gear door; with some accumulation near the door hinge. I returned to the cockpit; notified maintenance; and entered the Maintenance Required Code at XA:11; 18 minutes prior to scheduled departure. I went back to the ramp to confer with maintenance and waited a few minutes for a Mechanic to arrive. At about XA:20; a Mechanic arrived at the aircraft; quickly wiped the hydraulic fluid off the gear door; but looked no further than at the surface of the gear door. When I asked him if he intended to release the aircraft he responded 'Yes; that's why I'm the mechanic and you fly the airplane'. I explained that I would refuse the aircraft unless they looked beyond the surface of the aircraft for the source of the hydraulic fluid. A Maintenance Supervisor then appeared without identifying himself and confronted me. At my request; they opened the gear doors to look further; and with no obvious fluid accumulation in the gear well; I agreed the aircraft was airworthy and returned to the cockpit 2 minutes after scheduled departure time. Someone who identified himself as a Mechanic then requested via Interphone that we pressurize hydraulics to close the gear doors. I was then surprised to see that a Maintenance Release clearing the hydraulic fluid log item; had been generated at XA:20; the time at which the mechanic first arrived at the aircraft; before the gear well inspection took place. We completed our setup and departed 12 minutes late. It appeared that this station's Maintenance was spring loaded to release the aircraft without knowing if the hydraulic fluid was from an active leak. It also appeared the Maintenance Release was generated more that 15 minutes prior to the completion of the aircraft inspection. If safety is #1 priority at this air carrier; the manner in which this potentially serious maintenance issue was handled fell short. Maintenance demonstrated a somewhat belligerent attitude to this Captain; who is the final authority for the safety of the flight. The delay was improperly attributed to the cockpit crew; and the integrity of the maintenance release process was compromised.