I pulled both back wheels off today to inspect the brakes for the 1st time as I make my way around this car. The rear driver side brake was very "wet" in appearance and had mountains of wet road grime behind the backing plate. The innards were very clean. The springs, cylinder and parking cable all seem fairly new. I am not sure if this wheel cylinder is leaking. It appears fairly new and I don't see any specific issues with the brake line attachment in the back. The Passenger side brake looked like it had never been touched. It was caked in dust and road grime and the innards and backing plate is clean and dry. Is the "wet" driver side indicative of a leak? I am currently on an empty brake system, The brake pedal slowly sunk to the floor over a few months but I assumed it was the original single pot MC which was leaking a small amount near the brake pedal on the interior. I have a dual pot MC I am going to install but wanted to take a look at each brake to tackle any shoes, springs, etc first. One more question, this is the first time I have come across the spring clip type shoe hold down. Can those be interchanged with the pin type if need