I was outside today messing around with my new project truck and noticed my dad's passenger side rear tire on his 99 F150 was wet. I ignored it thinking that maybe a stray dog had come by and pissed on his tire but a few minutes later I looked at the tire again and noticed the inside of the rim was covered also and I new that a saint bernard couldn't let out that much **** so I decided to inspect the liquid. After touching it with my finger and smelling it I realized it was brake fluid. I jacked up the truck and took the tire off and noticed the outside of the drum was wet also. I checked the brake line and it was dry so I removed the drum and checked inside of the drum and it was dry also. I then popped the hood and looked at the reservoir on the master cylinder and it was almost empty. So I refilled the reservoir put the drum back on and pumped the brakes a couple times and nothing leaked the brakes were tight and weren't spongy and now i'm confused. Does anybody have an idea where the brake fluid came from? Like I said the tire was almost completely covered and the reservoir almost dry but not a single leak to be found. Thanks!