I purchased the Wilwood brake upgrade for my complete kit and purchased an additional master cylinder so that I have separate Wilwood master cylinders for the front and back. I installed everything a few months back and had a few flairs that leaked. I took care of those, bled the brakes and all looked good. I am not to go kart stage yet. I am still sitting on jack stands so I have not "used' the brakes. Two weekends ago, while mounting my tires, I noticed brake fluid on the bottom of the rear calipers. It was not enough fluid to even cause a drip. There is no fluid on the floor, just on the bottom of the calipers and only the rear calipers. I've checked all my fittings/connections and have no fluid leaks there. I thought perhaps it was just left over fluid from the former leaking flairs so I wiped them off making sure both were clean and dry. I pumped the brakes and noticed the pedal was no longer as firm as it was earlier. After a few pumps, they firmed back up. I felt the bottom of the rear calipers and they were still dry so I'm thinking I'm good. Since then, about every other day, I have felt the bottom of the rear calipers and the fluid is back. I clean it but it keeps coming back. However, it is never enough to make it drip. I pump the pedal and it is soft but firms back up. The fluid level in the master cylinder does not seem to be dropping. This can't be normal or else it would be happening with the front calipers, right? Could I have bad calipers? If it were only one leaking I might conclude that it is defective but it seems unlikely that I would have received two bad rear calipers. Any one else experience this? I don't want to take any chances with something as important as the brakes. Any suggestions on what to do would be most appreciated.