So I have noticed recently I have been having a random soft pedal with my R53. Some background info, car has 168k SS lines all around, Wilwood 4 pistons upfront, solid sliders in the rear. I usually flush the brake system once a year or every other, depends on how much/ how hard I have been using it. Haven't daily driven it for the past 8k so it sits a lot. My issue I am having is I randomly get a soft brake pedal, I haven't noticed it going to the floor but I hit the brake and expect to stop and pretty much I don't, once I release the pedal and hit it again its nice and firm like there was never anything wrong. This issue seems to happen at random and I have not been able to pin point any conditions that it occurs more in than not. Reservoir is nice and full and last I checked I had plenty of life on the pads. My first thought is there is air in the line but I would think the pedal would be soft all the time, the other was a leak but the reservoir wouldn't stay full if this was the case. The last though is maybe the master is on its way out. Has anyone had similar issues, trying to figure out which direction to head in first, should I try bleeding the system or just say screw it and replace the master anyways seeing it has a lot of miles.