A B767-300 Captain raises concerns about his Air Carrier's Maintenance department's policy of not allowing their mechanics to work deferrable aircraft discrepancies unless the pilot refuses the aircraft. Reporter stated his Chief Pilot had previously stated that was not the way their Carrier does business.

Narrative

Scheduled departure XA:05pm Local time. [Approximately a half hour earlier] during pre-flight; I tested the Weather (WX) Radar and it came up; 'WX Radar Fail; Weak RT'. I sent in a maintenance code over ACARS; and called Maintenance on the radio to let them know about the problem. A Mechanic was in the cockpit within about five minutes and found the same thing. Intermittently; the Radar Test would fail. We talked about our options. Initially; I told the Mechanic that weather was moving into the ZZZ1 area and the forecast was for rain at our arrival time; that I would like to have the Radar working. At that point he was going to leave to go see if there was a part. As he left I said I would call Dispatch to check on the weather and see if we had any alternatives. Just before he left; he said; 'I already know; even if we have a part; they won't work the problem unless you refuse the plane'. I said that I understand; but let's see if we have a part and get the process started while I call Dispatch. He agreed; pulled and tagged the WX Radar Circuit Breaker (CB); and left. I used the jetway phone to call Dispatch and see if we needed to have the Radar; or possibly arrive before the weather and go with it deferred; inoperative. The conversation with the Dispatcher lasted quite a while; he consulted with the WX Forecasters about any change in the forecast. We concluded that it would be OK to go without the Radar. The enroute weather was not a factor; and we would arrive just before the weather. Winds would be picking up; but no rain just yet. Before I hung up; I told the Dispatcher that I would still rather we had the Radar working; but we could go without it if necessary.I had not heard back from Maintenance yet about part availability. The time now was about XB:10 pm. Then I called Maintenance on the phone; the guy who answered said that they did not have a part and they were still waiting for the aircraft refusal to start the work. There was a plane at the hangar they were going to rob [cannibalize] the part from. I asked how long this was going to take. He said 20-30 minutes; but in my experience; any time a part is taken from another plane; particularly from the hangar across the airport; it is a minimum of an hour wait; and there was still the possibility that the part would not fix the issue. Time was a factor; if we left soon; we could go without the Radar; if we waited for the part and it wasn't fixed; then the weather would be there and we would require a working radar and possibly cancel the flight. I decided that we could go without the Radar; and to close up the plane; defer the Radar and issue a new Maintenance Release (MR). This was about XC:20pm. The Maintenance guy on the phone was not happy; and basically said OK and hung up on me. It took another 25 minutes to close the avionics access hatch; and accomplish a five-minute Checklist for the Radar deferral. We left 40-minutes late. It comes down to this; several months ago our System Chief Pilot put out a system-wide E-note saying that pilots did not have to refuse a plane to get it fixed; that our Air Carrier did not operate this way. However; the Line Mechanic said his Supervisors would not let him work the problem; and the Maintenance Supervisors in Maintenance said that they would not work the problem or fix the Radar unless I refused the plane. The Line Mechanic was very good and wanted to fix the problem; but he said his Supervisors would not authorize fixing anything without a refusal. After re-evaluating the initial decision with more input from the weather forecast and Dispatch; we ended up not needing the Radar but the story from Maintenance was that they were not going to fix the plane without a refusal; contrary to our System Chief Pilot policy. As a pilot; I require information from many resources; and a continual re-evaluation of options and decisions based on this input. The process worked and we were able to depart instead of canceling the flight. Pilots should not have to feel pressured into taking a deferral because they have to refuse the plane to get it fixed; as was the case here. This refusal process actually takes longer to process in many cases than it would take to just fix the problem; thus resulting is an even longer delay.