I seem to have a brake leak some where. I believe it is the front passenger side. When I take the tire off and have some one press on the brakes while it is running I can turn the brake rotor with little to no resistance. But on the driver side it is impossible to turn it when the brake is pressed. There is no sign of fluid by the caliber's or anything. But the back brake fluid reservoir is loosing fluid. (I've been told the rear reservoir is for the front brakes). Also it seems I gained a new issue when the brakes quit well there just really soft and go to the floor now. Also when I turn the key off it does not want to shut off before it would shut off right away no problem. Do I have a bad brake cylinder and its leaking into the brake booster causing bad vacuum? There looks like there may be a slight possibility that where the hard line comes out from the frame on the passenger side it looks like it might of been wet but it's kind of hard to tell and I cant see how that line runs back to the master cylinder. I'm leaning toward brake master cylinder because It seems I've lost vacuum pressure but if I pull a vacuum line off I still fill sucking. Any advice is greatly appreciated. 85 300sd w126