So I went out for a drive this evening in my R/T. It's been sitting outside all week so I try to drive at least until it gets up to operating temperature since I don't use it as my daily driver. I recently had the leaf spring shackles, spring bushings, rear shocks, and sway bar links replaced last weekend. So technically it's been outside in the cold without being driven until last Friday evening. I just drove it about 20-30 minutes. I noticed right away the brake pedal was sinking to the floor. If you pump it when you're coming to a stop it firms up some. I took it easy, just decided to drive around some of the neighborhoods until I could check it out. When I pulled back in I did a brief inspection and didn't see any obvious fluid leaks from under the master cylinder, front lines, rear hose, calipers, or on the back of the drums. When I got a couple years ago, not even 10,000 miles, I did front calipers, rotors, hoses and checked the rear. The rears looked almost new. I saw some bare metal areas under the master cylinder but not wet fluid. Fluid is still full. Do the wheels need to be removed fully to see or would it be noticeable on the back of the drums if a cylinder was leaking? I can see through the wheels on the front and all over the front calipers. They are all dry. Pads are almost 95% full. I did add speed bleeders on the calipers when I changed them. Any ideas what to check next?