I finished my roadster about 4 years ago and admittedly I don't drive it a lot (currently at 2600 mi, and car is stored from Oct-May each year). Issue began about a year ago when I noticed after not driving it for 5-6 weeks when I first got in and pressed on the brake the pedal initially would slightly "stick" as I pressed on it and then would seem to be fine although the pedal pressure seemed rather hard. Took it out for a drive recently and came to a light after a stretch of 55 mph road and as I pushed in the clutch the car had significant drag as if the brakes were being applied. Pulled over and felt all the calipers/rotors and the front calipers were too hot to touch. Sat there for about 90 min as they cooled off and was able at that point to move the car by pushing it (could not do that 90 min prior). Gingerly drove the car home the last 5 mi and started looking things over. Bled the front calipers (fluid looked discolored) and pedal pressure seemed softer than before. Test drove in a parking lot then out for a local drive and everything seemed better but with the exception of a softer pedal. Decided to bleed the rear lines after which it seemed like my pedal pressure was way too soft. Re-bled the front calipers and as I opened the bleeder brake fluid started to come out for a short time as if under pressure. Now when I pump up the brakes I build pedal pressure but it doesn't seem to hold for more than a minute after letting the pedal "rest". Checked everywhere and there are no leaks. Given the lack of use and the initial event of hot front calipers I'm thinking this is an issue with the front caliper pistons? Since I can build pedal pressure I'm hoping its not a M/C issue since getting those out will be a real pain. Any thoughts would be greatly appreciated!
N.B- currently waiting on spindles for a Coupe build, considering taking the Wilwood calipers I have new in box and throwing them on the front of the Roadster to see if that solves the issue

